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Epidemiology

An Unintended Casualty Of COVID: Tuberculosis

Currently, 2 billion people are infected with tuberculosis, about one-quarter of the world’s population. It lies dormant in most people but every year, it causes active disease in 10 million people and 1.6 million die of it. It is the number one cause of infectious disease-related death in the world. In the United States, healthcare providers are required by law to report cases of TB to health departments and the health departments in turn do contact tracing to identify and test others who could potentially have been infected. Because of this reporting requirement, we have very good epidemiological data about tuberculosis in the U.S.

Tuberculosis control in the United States has generally been a success. The number of new cases of TB per year has dropped from 84,304 in 1953 to 8,916 in 2019, a nearly 10-fold drop in cases. Because the United States total population has grown during this time period, the reduction in new cases per 100,000 population has dropped even more dramatically from 52.6 in 1953 to only 2.7 in 2019, a nearly 20-fold drop in case rates. This is a testament to the effectiveness of public health measures. Indeed, quarantining and the wearing of masks is nothing new – they have been our primary tool for controlling the spread of TB for more than a century.

The reduction in TB cases has not been linear. There was a spike in cases in 1975 that was largely related to a different surveillance case definition instituted that year and not due to an actual increase in TB in the United States. There was also an increase in cases in 1989-1992 that was primarily due to a surge in the number of people with AIDS in the U.S. But for the past decade, there has been a steady reduction in cases of TB in the U.S. by about 2-3% per year between 2010-2019. But then an unexpected thing happened in 2020. There was a 20% reduction in tuberculosis.

 

It turns out that COVID-19 has been our most powerful weapon yet in combating tuberculosis. The COVID-19 pandemic brought with it mandates of social distancing and face mask-wearing in public. These are reasonably effective means of controlling the spread of the coronavirus but they are even more effective in controlling the spread of other respiratory infections, including tuberculosis. Prior to 2020, the main indication for healthcare workers wearing N-95 masks was when caring for patients with known or suspected tuberculosis. Hospitals throughout the U.S. maintained a small number of “negative airflow” patient rooms, primarily to house patients suspected of having TB. But TB had become relatively rare to the point that most medical students do not encounter a patient with tuberculosis during their training; in 2019, there were only 150 cases of TB in the entire state of Ohio.

Most cases of tuberculosis in the U.S. occur in people who immigrated to the United States. For the past decade, foreign-born people have accounted for about 71% of the cases of TB in the United States whereas U.S.-born people have accounted for about 29% of cases. These percentages did not change in 2020 and therefore, the drop in new cases of TB cannot be attributed to reduced immigration to the United States related to COVID-19 travel bans. Furthermore, 90% of foreign-born people do not develop active TB until they have been in the United States for > 1 year, meaning they enter the U.S. with dormant (latent) TB and only go on to develop active disease years later.

Not only have the infection control measures used to slow the spread of COVID-19 been effective in reducing tuberculosis, these measures have been even more effective in reducing influenza. The graph above is from the Centers for Disease Control showing that the incidence of influenza this season (red triangles) is by far the lowest of any year in the past decade.

With 2 billion people infected, tuberculosis will not be eliminated in our lifetime. But it appears that COVID-19 has given us an unexpected step forward in our efforts to reduce TB in the United States. Tuberculosis data reporting in the rest of the world is not as robust and in the United States so it will likely be a few years until we see if the same phenomenon seen in the U.S. in 2020 will also be seen in other countries.

Hopefully, another benefit of the COVID-19 pandemic will be the accelerated study of mRNA vaccine technology that could offer hope of future vaccines effective in preventing tuberculosis. Regardless, the reduction in TB last year has been a very thin silver lining in a very large dark cloud of COVID-19.

April 17, 2021

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Epidemiology

COVID-19 Vaccine Side Effects (and how to prevent them)

I’ve been working at our medical center’s COVID-19 vaccine clinics for the past couple of months. We vaccinate about 3,500 people per day at our OSU Schottenstein Center site (the basketball arena) and about 275 people per day at our hospital-based vaccine clinic. Because of the potential for allergic reactions, we have either an emergency medicine physician or a critical care physician on site to manage any reactions. After supervising thousands of vaccinations, I’ve learned a lot about the vaccine reactions that people can get.

Younger people have more side effects

COVID-19 infection is much more severe the older we get. For people over age 80, the mortality rate of the infection is about 25% but for people under age 18, the mortality rate is negligible. It is just the opposite for side effects from the COVID-19 vaccines: older people are less likely to have side effect than younger people. I’m always relieved when I look over the list of the day’s vaccination schedule and see mostly people over age 60 because I know that I’m going to have an easy day.

Sore arms

Most people (about 75%) get a sore arm after the vaccination. It doesn’t typically occur for several hours after the injection and goes away within 2 days. I liken it to a bit more soreness than flu shot but less soreness than a tetanus shot. As with most other vaccines, the COVID-19 vaccines are given intramuscularly, into the deltoid muscle in the upper arm. One simple way of minimizing arm discomfort after the vaccination is to be sure that the arm is relaxed as much as possible when the needle goes in. If the deltoid muscle is tense when you get your vaccination, you are more likely to have pain later on. If there is swelling and redness at the injection site, a cold compress can help. If there is significant pain, it is OK to take acetaminophen (Tylenol) or whatever non-steroidal anti-inflammatory drug (eg, ibuprofen or naproxen) you normally take. Do not take any medications preventively and only take them if symptoms develop. Avoid taking corticosteroid medications (eg, prednisone) to treat arm pain or swelling since steroids can reduce the body’s immune response to the vaccine. If you anticipate needing to do a lot of writing or some other activity that involves your dominant hand, then get the vaccine in the non-dominant arm.

Aches, fever, and chills

It is difficult to predict who will get muscle aches, headaches, chills, or fever after the COVID-19 vaccine. The good news is that most people do not get these side effects. In general, younger people are more likely to get them than older people and people are more likely to get them after the second dose than the first dose. People who have had COVID infection in the past are also more likely to get more vaccine side effects, especially with the first dose of a vaccine. Although the timing can vary, it is typically about 18 hours after the vaccination. It is a good idea to have acetaminophen on hand and then take it at the early signs of fever or body aches in order to prevent experiencing more severe symptoms. For most people, these side effects resolve by 36-48 hours after the injection. The important thing to know is that these symptoms are NOT an indication of an infection and are instead an expected reaction of the body’s immune system to the vaccine.

Fatigue

Many people will be tired the day of and after their vaccine. For some, this can be severe enough to stay home from work. Because of this, we tried to stagger the vaccinations for our operating room nurses and the nurses on individual nursing units since we knew that a percentage of them were likely going to call off work the next day. Similarly, if you operate a restaurant or store, try to keep all of your employees from getting vaccinated on the same day or you might find yourself having to close shop the next day. To minimize fatigue, keep hydrated and plan on an extra 1-2 hours of sleep the night after your vaccine. An afternoon nap may be in order, also.

Anaphylaxis

This is the most serious side effect of the COVID-19 vaccines and it is fortunately vary rare. This is a severe allergic reaction that can cause difficulty breathing and shock. It occurs shortly after the vaccination, within the first 30 minutes. It responds very well to epinephrine injection and we keep epinephrine on hand, just in case of anaphylaxis. In my own experience, many of the people who were initially thought to have anaphylaxis didn’t actually have it – vocal cord dysfunction and vagal reaction are common masqueraders of anaphylaxis (and far less serious). The main component of the Pfizer and Moderna vaccines that can cause severe allergy is polyethylene glycol. This is the same ingredient in the laxative, MiraLAX, and the prep used for colonoscopy, Go=lytely. If a person has not had an allergy to these ingredients in the past, then they usually do not have any problem with the COVID-19 vaccine.

Rash

Less life-threatening allergic reactions can show up with a rash or itching, rather than anaphylaxis. These reactions are also quite uncommon but can be fairly easily treated with antihistamines (eg, Benadryl). Isolated rash does not warrant a trip to the emergency department but these patients should be watched a little longer than other patients to be completely sure that they do not progress to anaphylaxis.

Avoidable side effects

By far, the most common symptoms we see at the time of vaccination are avoidable:

  • Vagal reactions. This is what happens when a person faints and a lot of people faint at the sight of needles, regardless of what is inside of that needle. If a person is going to develop a vagal reaction, then they will develop it even if there was nothing in the syringe. The symptoms are feeling light-headed, clammy, nauseas, and sweaty. One of the best ways to prevent a person from having a vagal reaction to a COVID-19 vaccination is to distract them by talking to them while the nurse is giving the vaccine in order to take their mind off of the vaccine. When someone does develop a vagal reaction, have them lay down, preferably with their feet elevated. If a person tells you that they faint or get dizzy every time they get a vaccine, then put them in a reclining chair before you give them the COVID-19 vaccination. Ensuring that the person is adequately hydrated is important. The most common treatments that I give out in the vaccine clinics are bottle of water.
  • Hyperventilation. Many people are afraid of vaccinations and doubly afraid of the COVID-19 vaccine. Maybe they read something written by an anti-vaxxer or maybe they heard a horror story from their neighbor about how awful the neighbor felt after their vaccination. These patients are prone to panic attacks. The symptoms are dizziness, shortness of breath, and tingling in the fingers and hands. From a physiologic standpoint, these symptoms are caused by an acute respiratory alkalosis causing the pH of the blood to rapidly rise – this is due to breathing too rapidly and too deeply. Patients who get hyperventilation after their COVID-19 vaccination need to be talked down from it – focus on slower and shallower respirations. This can be hard to do since the rapid, deep breathing is being caused by anxiety. Reassurance and having the person breath through their nose (rather than mouth) is usually all it takes. Once patients realize that the symptoms are from hyperventilation, they usually calm down. In the past, this would have been treated by breathing into a paper bag to re-circulate carbon dioxide and prevent the blood carbon dioxide from dropping too low.
  • Hypoglycemia and dehydration. This is by far and away the most common problem that I encounter at our vaccine clinic. It is also a risk factor for vagal reactions. Many people get up in the morning and go straight to the clinic to get their COVID-19 vaccine before they have breakfast. Couple an empty stomach with the fear and excitement of a vaccine and you get a bunch of queazy, dizzy vaccine recipients. Encourage people to have breakfast before their vaccine and keep up with their fluids. This can be an especially big problem when we are vaccinating college students on the weekends who stayed up late the night before drinking beer. Being dehydrated and having an empty stomach is a set-up for getting a vagal reaction
  • Grouchiness. This is another very common symptom we see in the vaccine clinic and is usually caused by hypocaffeination. Just like skipping breakfast before your vaccine is a bad idea, skipping your morning coffee can result in having a headache, feeling tired out, and having a generally bad attitude. If you are a coffee or tea drinker, have a cup before you go to the vaccine clinic.
  • Vocal cord dysfunction. In the pulmonary clinic, vocal cord dysfunction (VCD) is a common mimic of asthma. It occurs when the muscles that control the vocal cords are under excessive tension resulting in the space between the vocal cords being constricted and too narrow. This causes shortness of breath, particularly when trying to breath in (as opposed to breathing out). Some patients will say that they they feel like air is getting stuck at the top of their neck. Anxiety can precipitate vocal cord dysfunction. One of the problems with VCD is that it can not only mimic asthma but can also mimic anaphylaxis and the treatment for anaphylaxis (epinephrine) can often make the VCD worse. In our vaccine clinic, I saw a person who was their for their second dose of the COVID-19 vaccine. With the first dose, she had developed what was thought at the time to be anaphylaxis and was given epinephrine that did not help and in fact seemed to make her breathing worse. The EMS squad was called and took her to the emergency department where a particularly bright physician obtained a blood tryptase level. Anaphylaxis causes the tryptase level to be elevated and hers was normal. For her second dose, we had a nurse sit with her and provided lots of reassurance and distracting conversation. We told her to breath through her nose (which can help reduce the tension on the vocal cords). In the end, she had no problems at all after her second dose. With all that being said, VCD is never a life-threatening problem but anaphylaxis is – when in doubt about whether it is VCD or anaphylaxis, treat the persons as if it is anaphylaxis.
  • Boredom. You can always pick out the people who are in the vaccine clinic for their second dose (as opposed to their first dose). They bring a book, newspaper, or crossword puzzle. Sitting in the clinic for 15 minutes with nothing to do except look at the other people getting vaccinated can be pretty boring and that boredom can be double the amount if you have to wait 30 minutes because of a past history of severe allergies.

The COVID-19 vaccines are safe. Period. Yes, they can sometimes have annoying side effects but no one dies from the COVID vaccine whereas more than a half of a million Americans have died of COVD-19. By getting a COVID-19 vaccination, you are saving a life – if not yours, then one of your family members or someone in your community. A sore arm or fatigue for a day is a small price to pay.

April 3, 2021

Categories
Epidemiology

Who Should Be Prioritized To Receive COVID Vaccinations?

One sure way to elicit an “OK boomer” comment from anyone under age 50 is to quote the comic strip, Pogo. In the War of 1812, naval commander Oliver Hazard Perry defeated the British navy in the Battle of Lake Erie and messaged the military leadership “We have met the enemy and they are ours”. In 1970, Pogo creator, Walt Kelly, satirically paraphrased Perry’s message in an Earth Day commentary about pollution by having his character say “We have met the enemy and he is us”. A half century later, Pogo’s statement could also be applied to prioritizing COVID-19 vaccinations: “We have met the COVID special interest groups and they is us”.

When it comes to the COVID vaccine, there are two types of people, those who are not going to get it because they fear it and those who want it as well as believe that they should get it before anyone else.

When the vaccines were first authorized for use by the FDA in December 2020, each state was directed to make its own criteria for which groups of people would receive the vaccine first. The CDC and the FDA provided general recommendations but this was really a “state’s rights” issue. Most states initially approved vaccinating healthcare workers, followed by different at-risk groups.

On the surface, vaccinating healthcare workers made perfect sense – these are the people who were risking their health and their life exposing themselves by caring for patients infected with COVID. Furthermore, we need healthy healthcare workers to take care of patients hospitalized with COVID. But should all healthcare workers be prioritized ahead of the rest of the population? Across the country, hospitals developed a process for ranking their employees for who should get the vaccines in what order. Some categories of healthcare workers were easy, for example, emergency department and intensive care unit nurses. But after that, things get a bit controversial.

What about the nursing unit clerk who does not have direct contact with COVID patients but is working at a desk down the hall from sick patients? What about the primary care physician who does not care for patients in the hospital but might encounter a patient with undiagnosed COVID coming into the office with sinusitis symptoms? What about the facilities worker who might be called to do a repair in a hospital room with a COVID patient in it? What about the billing office staff who are working from home but who are essential to keeping the hospital open and running? What about healthcare professions students who are not permitted by their school administration to care for COVID patients but could encounter a patient with asymptomatic COVID infection during a clinical rotation??

Throughout the country, each of these groups of healthcare workers started lobbying that they should receive the vaccine or that they should be moved up on the prioritization list. In January, media coverage exposed hospital board members, hospital staff working from home, and health profession students who were not providing direct patient care to COVID patients. This resulted in outrage by state legislators and governors across the nation who directed that vaccine prioritization move to non-healthcare worker groups.

Many states next prioritized nursing home residents and workers. This made a lot of sense because these patients were not only at high risk of being hospitalized or dying if they got infected but because they live in confined areas close to a lot of other nursing home residents, they were more likely to get infected than people who lived independently in their own home and could isolate themselves. But what about people who live in other congregate settings such as college dorms, homeless shelters, and prisons? At the beginning of the pandemic, many prisons in the United States experienced outbreaks of COVID with large numbers of inmates and guards becoming infected. In several states, these outbreaks among prisoners were of sufficient magnitude to overwhelm hospitals to the point that it became difficult to provide care to regular citizens. In response to this experience, some states prioritized prisoners and the homeless for getting vaccinated resulting in outrage by regular tax-paying citizens.

Some states prioritized people with various diseases. This immediately created lobbying by people with one disease to be prioritized over people with other diseases. Should people with asthma be prioritized before people with COPD? Should people with type I diabetes be prioritized before people with type II diabetes? Should people with cystic fibrosis be prioritized before people with pulmonary fibrosis? In Ohio, asthma, type I diabetes, and cystic fibrosis were prioritized over the other conditions. The whole idea of lobbying is to convince governments to give something to one group instead of another group. As with all lobbying, the decisions made by states about which diseases should be prioritized first werenot often not made based on the science of epidemiology but rather based on which group could most eloquently and effectively lobby to get vaccinated first. Moreover, how do you prove that a person has a particular disease? Do they need to have a note from their doctor or do they just need to say that they have one of the diseases when they show up at the vaccination site?

Another group of citizens to be prioritized  were “essential workers”. Depending on your vantage point, more than half of employed people in the U.S. are “essential”. Where do you draw the line between grocery workers, restaurant workers, members of the military, farmers, teachers, government workers, and manufacturing workers?

The least controversial prioritization grouping was by age. The probability of being hospitalized or dying if a person becomes infected with COVID is directly related to that persons age. People < 18 years old have an exceedingly low COVID hospitalization rate and mortality rate. People > 80 years old have a 25% COVID mortality rate. By using age as a criteria, lobbying is eliminated – a lobbying group for people 60-65 years old is not going to demand that their constituency be vaccinated before people 70-75 years old. It is easy to provide proof of eligibility – all you need to do is show your driver’s license or other identification, you don’t need a letter from your doctor stating that you are 68 years old.

From a societal standpoint, vaccine prioritization should be guided by:

  1. Which people are at highest risk of death or disability if they get infected 
  2. Which people are at highest risk of creating a lot of expense if they get infected
  3. Which people cause the greatest societal disruption if they get infected
  4. Which people are most likely to get infected
  5. Which people are likely to spread the infection to others if they get infected.

The first two groups of people are the same – those who create the greatest expense are those who get hospitalized and these are the people who are most likely to die. Age is clearly a leading predictor of death and hospitalization. People older than age 85 years infected with COVID are 80 times more likely to be hospitalized and nearly 8,000 times more likely to die than people under age 18 infected with COVID.The table below from the Centers for Disease Control shows the risk of hospitalization and death from COVID infection by age.

Other strong risk factors for hospitalization and death from COVID-19 are obesity, chronic kidney disease, diabetes, and hypertension. Because there are varying degrees of obesity, hypertension, kidney disease, and diabetes, it becomes very difficult to decide where to draw the line by BMI, systolic blood pressure, creatinine level, and hemoglobin A1C.

The second and third of these groups require even more value judgement. For example, does a firefighter who has to go out on sick leave result in more social disruption than a grocery worker who has to go out on sick leave? We know that certain racial groups are more likely to become infected than others so should people belonging to one race get vaccinated before people belonging to other races?

Ultimately, nearly all of us are in a COVID vaccine special interest group and can think of some reason or another for why we should be vaccinated before the rest of the population. In many ways, this is better than the alternative of no one wanting to get vaccinated. Fortunately, the number of new cases of COVID is falling and the amount of vaccine is increasing, so soon, everyone who wants a vaccine will be able to get one. Until then, maybe we should just keep things simple and use age alone as the criteria for prioritizing vaccination.

February 25, 2021

Categories
Epidemiology

Anti-Maskers And The Company They Keep

Anti-maskers are flourishing in the era of COVID-19 but they are not new. During the 1918 influenza epidemic, the wearing of masks was mandated in many U.S. cities and “mask slackers” rebelled with one Portland, Oregon city council member arguing “Mask requirements are autocratic and unconstitutional; under no circumstances will I be muzzled like a hydrophobic dog.” The anti-maskers never went away during the past century, they’ve been quietly meeting in secret, just waiting for a new pandemic to happen so that they can once again profess the dangers of wearing masks. So, who are these anti-maskers? Most are members of a fraternity of organizations whose mission is ostensibly to protect personal liberties. Here are some of these other organizations in the fraternity of the anti-maskers:

The Anti-Hand Washing League. This secret society was created in 1848 to combat the hand washing hysteria being propagated by Dr. Ignaz Semmelweis, the physician on the lunatic fringe of medicine who had the audacity to recommend that doctors wash their hands after performing autopsies. The League’s mission is to globally eliminate hand washing in order to preserve the natural body oils of the hands. Says League president Max Saponify, “Requiring me to wash my hands after using the toilet is an infringement of my constitutional rights!

The Federation Dedicated to a Deodorant-Free World. This group has a goal of global elimination of antiperspirants and deodorants. “These chemicals are a well-known cause of armpit cancer” says Federation chairman Axilla LaPue. The Federation’s motto is that “A man should smell like a man… and a bear,… and a boar,… and a Tasmanian Devil”. Many members are also affiliated with the Anti-Bathing Guild whose motto is “Satan made soap”.

The Stogies in School Society. Formed after municipal laws against smoking in public were enacted in the early 2000’s, the Society’s mission is to preserve the rights of middle school students to smoke cigars in class. A side project of the Society is the “Spittoons in Church” project to promote legislation requiring all churches to provide spittoons in the pews for parishioners who chew tobacco during services.

The Pull My Finger Association. This organization is committed to the promotion of public flatus. The annual meeting is held in Boston every December and culminates with the group’s baked bean dinner followed by the flatus a cappella contest. Last year’s winner was the Central City Cheese Cutters with their rendition of Bob Dylan’s “Blowing in the Wind”. Afterward, the attendees went caroling in downtown Boston with their unique wordless Christmas carols.

The Anti-Vaxxers. This mainstream group opposes vaccines of all kinds. Said one anti-vaxxer: “They say vaccines prevented smallpox and polio. I don’t know anyone who ever had polio or smallpox. I think drug companies just made up those diseases so they could scare people into buying their vaccines.” Group members have determined that vaccines cause disease. “You get a flu shot and your bowels will be irregular for months… not for me!” wrote another member in a letter to the editor of the Cowtown Gazette. The group points to the Will Smith movie I Am Legend as evidence that vaccines turn normal people into flesh-eating zombies.

The Free the Snot Foundation. Dedicated to liberating oppressed nose mucus from confinement in Kleenex and handkerchiefs, the FSF is considered by some to be a terrorist group, spewing unsuspecting passersby with nasal secretions. Among the group’s more mainstream activities is the annual “Shoot the Snot” contest to see which contestant can propel sinus secretions the farthest. The current world record is held by Charlie “Booger” Snout with his 2015 performance of 15 feet, 3 inches. But a darker side of the Foundation is the rumored rite of passage for admittance that allegedly requires initiates to clandestinely launch snot over the rail of the Empire State Building creating the so-called “rhinitis rain” that the City of New York is widely known for.

The Anti-Trouser Alliance. This male-only organization seeks to overturn local ordinances requiring men to wear pants. “If God wanted us to wear them, we’d be born with pants” said the Alliance’s spokesman I. M. Stark. The Alliance’s annual project this year is the “Butts on Buses” initiative to promote the freedom to sit on public bus seats pants-free. The initiative was conceived after the enormous success of the “Butts on Banisters” project last year.

The MPH Liberation Club. This group hopes to eliminate speed limits in school zones. “Those roads were built with my tax dollars. If I want to drive 60 miles an hour in front of St. Mildred’s Elementary School, then it should be my right!” said member Phlatt N. Quash. The group also seeks to eliminate stop signs, traffic lights, and center lane lines on public roads.

The Sidewalk Turd Confederation. The Confederation’s mission is to eliminate public bathrooms. It is composed of individual groups including libertarians that want to eliminate highway rest areas in order to reduce government costs, the gas station worker’s union that objects to requiring employees to mop restroom floors, and environmentalists seeking to save trees by abolishing toilet paper. Said the Confederation’s Secretary General, P. N. Yard, “Squirrels do it, birds do it, dogs and cats do it. Don’t we have the same rights as the animals?”

The Yell “Fire” In Movie Theater Consortium. This organization’s goal is to preserve the First Amendment right to free speech. Members are encouraged to walk through maternity wards and randomly tell new parents that they have an ugly baby, to tell their mother-in-laws that her cooking is terrible, and to  shout “Shark!” at public beaches.

Anti-mask = Anti-business

The reality is that masks work. The COVID-19 virus is spread through the respiratory tract – when you cough, sneeze, or talk loudly, you exhale viruses. If you want to stop a respiratory virus from spreading, you have people wear masks to catch viruses contained in exhaled breath. Wearing masks is the fastest way to re-open stores, stadiums, bars, churches and restaurants. Anti-maskers have the confused notion that masks infringe on their human rights; the reality is that the more people wear masks, the sooner the economy recovers and jobs return. Don’t be a member of one of these fraternal organizations, wear a mask!

November 1, 2020

 

Categories
Epidemiology

(Age + BMI) x Hemoglobin A1C = COVID Mortality Risk

OK, not really. This title is not a scientifically-proven equation and so don’t quote me on it. But it does underscore the observations that there are both powerful modifiable risk factors and non-modifiable risk factors for death due to COVID-19. We started anecdotally noticing this in our ICU in the spring as the COVID-19 outbreak unfolded in Ohio. Patients who ended up in the ICU and who died were older and/or had co-morbid diseases. And since then, several studies have confirmed these observations.

Age is the strongest risk factor for death from COVID-19. In a previous post, I noted that in a report of COVID-19 infections in California, for people under age 18, death from COVID-19 infection is exceedingly rare. But for every decade older, the risk of dying if a person becomes infected increases, culminating with a 25% mortality rate in those over age 80. This striking of an age effect on mortality is not seen with other respiratory viruses, such as influenza, which causes death in both the very young and the very old. This was especially true of the influenza pandemic of 1918 and the H1N1 pandemic of 2009 when younger persons who became infected had a higher mortality than older persons.

Obesity is also a predictor of death from COVID-19 infection. In a study of 17 million people in England, morbid obesity (BMI > 40) was associated with a 2-fold risk of dying from COVID-19. This may be why the United States has been so disproportionately affected by COVID-19 compared to other countries. According to the Organisation for Economic Co-operation and Development (OECD), the United States has the highest prevalence of obesity of all developed nations with 40% of Americans having a BMI > 30. In contrast, the average prevalence of obesity in OECD countries is only 24%.

Obesity goes hand-in-hand with diabetes and so not surprisingly, uncontrolled diabetes is also a risk factor for death due to COVID-19 infection. The same study from England found that uncontrolled diabetes (defined as a hemoglobin A1C > 7.5%) conferred a 2-fold increase in likelihood of dying from COVID-19 compared to a normal hemoglobin A1C. Once again, the United States has a higher prevalence of diabetes than the world as a whole with 10.8% of Americans being diabetic and 8.8% of the world being diabetic according to data from the world bank. The U.S. leads all other large developed nations with regards to diabetes prevalence. Like obesity, uncontrolled diabetes is a modifiable risk factor. Obese persons are more likely to become diabetic and diabetics with reduced access to healthcare are more likely to have uncontrolled diabetes. Despite spending more money per capita on healthcare than any other country in the world, Americans see a physician fewer times per year (4) than inhabitants of other OECD nations (6.6) suggesting that the access to healthcare in the United States is actually quite low compared to other countries.

Whether or not a risk factor is considered modifiable or non-modifiable depends on the event horizon of the disease in question. A disease like coronary artery disease results in a fatal myocardial infarction years or decades after coronary artery disease first begins. This gives people ample time to modify their risks for coronary disease. With COVID-19, the event horizon is short and measured in weeks and months, not years. Thus, the “modifiable” risk factors needed to be modified years ago in order to reduce the chance of dying of COVID-19 next today. It is not possible to significantly lower one’s BMI or hemoglobin A1C fast enough to make much of a difference of surviving the current pandemic.

But there are lessons to be learned. If you are 18 years old with a BMI of 22 and a hemoglobin A1C of 4%, then you have higher chance of dying in a motor vehicle accident than from COVID-19. But if you are 70 years old with a BMI of 40 and a hemoglobin A1C of 9%, you would be advised to find an abandoned missile silo, close the door, and leave it locked for the next 12 months.

August 29, 2020

Categories
Epidemiology

Mask Myths

One of the most effective ways of controlling the spread of respiratory viruses, such as the COVID-19 virus, is by wearing face masks. Last weekend at the Ohio Statehouse, a group of anti-maskers protested the wearing of face masks, complete with an escort of camo-wearing, body armor-clad, AR-15-wielding gun enthusiasts, presumably there to protect the protesters from throngs of violent mask-wearers. The protesters offered a multitude of reasons why people should not wear masks and so I thought this would be an opportune time to examine some common mask myths.

  1. You can get carbon dioxide poisoning. This theory espoused by anti-maskers proposes that carbon dioxide builds up inside of masks and then when one inhales, they inspire toxic quantities of carbon dioxide leading to disease and death. Carbon dioxide is a gas and cannot build up in a cloth or fiber mask. If it did, we would have to pay surgeons and OR nurses hazard pay since they have worn masks daily for decades. It appears that the protestors confused wearing a cloth mask with tying a plastic trash bag over one’s head.
  2. Masks cover up the image of God. This is the reason that state representative Nino Vitale from Urbana, Ohio used when he refused to wear a mask over his face inside the Ohio Statehouse. Mr. Vitale has quite a celestial opinion of himself and it is suspected that he refuses to wear pants in public for the same reason.
  3. Only N-95 masks protect you. N-95 masks are only necessary when performing aerosol-generating procedures and not when performing routing patient care or when out among the public. As long as you are not performing an upper endoscopy or colonoscopy inside of a McDonalds restaurant, you don’t need an N-95 mask.
  4. Masks only need to cover the mouth and not the nose. This one is partially true… as long as you are holding your nose, it won’t matter if your mask covers it. However, if there is air coming out of your nose, then it needs to be covered.
  5. If you’re not sick, you don’t need to wear a mask. Unfortunately, only about two-thirds of people infected with the COVID-19 virus have symptoms. In other words, one-third of those infected are asymptomatic. The guy sitting on the bar stool next to you who is yelling, laughing, sneezing, or coughing could quite easily be passing the virus on to you whether or not he has a fever.
  6. You only need to wear masks indoors. The idea is that sunlight kills the virus. Although it is true that most of the virus on surfaces is killed after about 20 minutes in direct midday sun, being in the sun will not kill viruses being passed through the air when someone coughs toward you, unless you can hold your breath for 20 minutes.
  7. Wearing a mask shuts down your immune system. Cloth masks are made of cloth, just like clothing is made of cloth. As long as your shirt is not causing you to get leukemia, your mask won’t either.
  8. Masks should be soaked in Clorox bleach before being worn. The idea behind this one is that since bleach kills viruses, any virus in the air that you breathe in will be dead-on-arrival when it gets into your lungs. Pulmonologists, such as myself, wish that this was true because if so, we would have lifetime job security from all of the asthma and lung damage caused by people inhaling bleach vapors.
  9. Wearing masks hurts the economy. Increasing numbers of viral infections hurts the economy. The economy will recover when it is safe to go to the store/theater/stadium/restaurant. Personally, I won’t walk into a public building if I seen other people not wearing masks. Wearing masks is the fastest way to rejuvenate the economy. Countries that enacted mask requirements early have recovering economies and are about to eat the United States’ lunch.
  10. Masks go against the American spirit of freedom. American freedom does not mean you have the right to infect other people with the virus. If a person is asymptomatically infected with the COVID-19 virus that person can infect others who are in contact with him/her. And if 4 of those others who get infected are over age 80, then statistically 1 of them will die. As a physician, I do not have the freedom to deny treatment to a mask-slacker who develops COVID-19 respiratory failure.

Anti-maskers join the legion of anti-vaxxers, anti-hand washers, anti-tooth brushers, and anti-bathroom users. Until we have an effective vaccine, the fastest way to get back to life as normal is to wear a mask.

July 22, 2020

 

Categories
Epidemiology

You Are Safer From COVID-19 In The ICU Than In The Grocery Store

This summer, COVID-19 numbers keep going up. Five months ago, we thought COVID-19 would behave like other respiratory viruses: have peak incidence in the winter and then drop off in the summer. But that has not happened. Across the United States, there is a second surge in new infections and southern states that seemed to be spared from the initial outbreak now have rapidly escalating numbers of new cases. As our hospitals admit record-breaking number of these patients, all of us in healthcare jobs wonder “Are we safe in our workplace?“. It looks like the answer is… we probably are.

In intensive care units full of COVID-19 patients, we are hyper vigilant about using personal protective equipment. Face masks, eye protection and hand sanitizer are mandatory. For patients undergoing aerosol-generating procedures, disposable gowns, gloves, and N-95 masks are added. It turns out that the coronavirus has a hard time penetrating all of that PPE to get to our mouths, noses, and eyes. Infection control procedures work surprisingly well.

The home is a dangerous place

On the other hand, in our homes, grocery store, bars, churches and restaurants, we let our guard down. The masks come off, we don’t use hand sanitizer every 5 minutes, and there are no plastic face shields to protect our eyes. Even worse are those around us who refuse to take any precautions, either because they believe that they are invincible, they are trying to make a political statement, or they are just plain ignorant. During the influenza pandemic of 1918, these people were called “mask-slackers”. Not only were there individuals who refused to adhere to infection control practices, there were entire cities that refused to adhere to these practices. St. Louis was an early adopter of closing schools and businesses whereas Philadelphia did not close businesses and instead held a public parade – the peak death rate in Philadelphia was 257/100,000 whereas the peak death rate in St. Louis was only 58/100,000.

A recent study from JAMA looked at 3,056 healthcare workers at a hospital in Belgium who underwent antibody testing to identify those who had become infected with the COVID-19 virus. All of them additionally completed a survey about exposures. 197 staff were identified as having been infected. But there was no correlation between taking care of COVID-19 patients and becoming infected oneself. Even working in the hospital was not associated with becoming infected. The only correlation was when a healthcare worker had a family member who was infected. The study indicated that healthcare workers who got infected did not get infected from hospital exposures but instead got infected from family members at home. U.S. hospitals are finding the same thing – when healthcare workers are identified as being infected, it is home exposures that are the cause and not patient exposures.

There are steps our hospitals can take

All of us in hospitals feel the risk. Many healthcare workers have decided to just retire or seek other jobs. Others have gone on disability purely due to perceived risk of becoming infected. But we know that strict use of personal protective equipment and hospital visitor limitation works. So what can we do to ensure our staff safety as elective procedures resume and visitors return? Fortunately, there are some specific things that we can do:

  1. Universal masking. Every person in the hospital should be wearing a mask unless they are alone in a room. This means not only doctors and nurses but also visitors and administrative staff. A mask for every person, all the time.
  2. Eye protection during patient care. In addition to face masks, goggles or face shields should be worn whenever a staff member is in a room with a patient.
  3. Hand hygiene every time. Alcohol hand sanitizer needs to be available throughout the hospital and must be used before and after every patient encounter.
  4. Beware of the break room. In hospitals, we often assume it is the patients who could be infected and are thus dangerous to us. However, we are more likely to get infected from a co-worker in the cafeteria, the conference room, or the office suite when we let our guard down by taking off our masks and not using hand sanitizer. It is probably more dangerous to eat in the doctor’s lounge than it is to intubate a COVID-19 patient while wearing PPE. When it comes to who hospital workers get their COVID-19 infection from, in the immortal words of Pogo: “We have met the enemy and they is us“.
  5. Limit visitors. Statistically, the more people that are in the hospital building, the more likely one of them is infected with COVID-19. Some studies indicate that as many as one-third of infected persons have no symptoms so simply screening visitors by symptoms or body temperature will not catch all of those people who can potentially spread the virus.
  6. PCR test all patients. Not only can visitors have asymptomatic infections but so can patients. So the patient coming in with appendicitis, a heart attack, or a bleeding ulcer can also have subclinical COVID-19. Every patient should be treated as if they have the infection until proven otherwise.
  7. Work from home. Healthcare workers can also have asymptomatic infection and so the fewer healthcare workers are in the building, the less likely one of them is going to inadvertently infect someone else. If you can do your job equally well from home, you should not be in the hospital.
  8. Encourage smart behavior outside of the hospital. We cannot control what our healthcare workers do when they leave the hospital but we can at least encourage them to do the right things. Avoid indoor gatherings. Always wear a mask in public. Avoid places where other people do not wear masks. Practice hand hygiene.

The COVID-19 virus is all around us. But it just may be that the safest place to be right now is working in the COVID-19 ICU.

July 19, 2020

Categories
Epidemiology

The Effect Of Age On COVID-19 Mortality Rates

Last week, I was asked if it would be OK if 20 family members visited one of my patients who is in his 80’s over the holiday weekend. My reflexive response was “Don’t come!” but it raised the question of what is the probability of dying should this patient get infected by COVID-19 and how does age effect mortality rates? Although we all know that age is a risk factor for death from COVID-19 infection, it turns out that specific probability statistics are hard to come by.

The U.S. Centers for Disease Control regularly posts information about the COVID-19 hospitalization rate by age and we know that older persons are more likely to be hospitalized than younger persons. For example, the hospitalization rate for people age 18-29 years old is 34.7 per 100,000 whereas the hospitalization rate for people over the age of 85 is 573.1 per 100,000. That means that an elderly person at 85 years old is sixteen times more likely to be hospitalized with COVID-19 than a young adult who is 25 years old. But this data does not tell us about the probability of death for different age groups.

The Ohio Department of Health regularly posts information about the number of Ohioans who have died from COVID-19 by age. This graph shows the COVID-19 deaths in Ohio as of July 1, 2020. It is striking that 1,516 deaths (53% of the total) occurred in people over the age of 80 whereas only 2 deaths have occurred Ohioans under the age of 20. However, the Ohio ODH does not post the total number of cases by age and so we still cannot determine the probability of death for different age groups. For that information, we have to turn to California.

The California Department of Public Health regularly posts both the number of infections AND the number of deaths for different age groups. This is the data from California as of July 1, 2020. By dividing the number of deaths by the number of cases for each age group, we can calculate the probability of death if a person in that age group becomes infected with COVID-19. The numbers are astounding: 25% or one out of every four people over age 80 who get infected with COVID-19 will die of the infection. On the other hand, a young adult between age 18-34 years old who gets infected with COVID-19 has a 0.084% chance of dying (or 1 death for every 1,196 infected persons). That means that an 85 year old person is 300 times more likely to die if infected with COVID-19 than a 25 year old infected with COVID-19. One a more personal front, if one of my children and I both get infected with COVID-19, I am statistically 38 times more likely to die than my child.

So, why is age such a striking risk for death by COVID-19? Although it is true that older people are more likely to have debilitating diseases such as heart failure and COPD that could make death more likely, I do not believe that this fully explains the association of age with COIVD-19 mortality. Furthermore, children almost never die of COVID-19; in Ohio, there have only been 2 deaths in those under age 20 and in California, there have been no deaths in those under age 18. One possible explanation that has been proposed is age-related changes in the level of the cell membrane receptor ACE2, a protein that the COVID-19 virus binds to in order to get inside of cells.

Virology research will eventually give us an answer to the question of why COVID-19 preferentially kills older people. But for now, I’ll stick to my original answer to my 83-year old patient’s family members question about having a family reunion at his house over the holiday weekend… don’t do it.

July 3, 2020

Categories
Epidemiology

Good News For The 2020-2021 Influenza Season?

I have a confession… I am a flu nerd. Every winter, I check the Center for Disease Control’s FluView website every Friday for epidemiology updates and I track the number of cases of influenza in our own hospital weekly. Most years, what happens in Australia in August and September predicts what will happen in the United States in February and March. And this year, there may be some good news from down under.

When it is summer in the United States, it is winter in Australia and so Australia’s flu season is the opposite months of the year as the United State’s. Last year, the Australian flu season was unusual: it started earlier in the year and there was a much higher percentage of influenza B than normal. Sure enough, last winter in the U.S., our influenza season also started earlier than normal and was characterized by mostly influenza B in the beginning of the winter and then mostly influenza A later in the winter. This graph shows the number of influenza cases by week of the year for 7 recent flu seasons (week 1 is in January). The red line is the 2019-2020 flu season (the gray line was the H1N2 pandemic of 2009).

Some studies of COVID-19 infections that occurred last winter indicated a high rate of co-infection with other viruses, particularly in children. The most common co-infecting virus was influenza. A fear of epidemiologists is that when the U.S. has its next influenza season in the winter of 2020-2021, co-infection of influenza and COVID-19 could result in an accelerated spread of COVID–19.

But it turns out that the same public health measures that help control the spread of COVID-19 also help control the spread of other respiratory viruses. Many physicians have wondered why there have been fewer emergency department visits for respiratory illnesses and fewer patients with asthma exacerbations in the past few months. The reason is likely because social distancing, wearing face masks, and frequent hand washing reduces the spread of all respiratory viruses, not just COVID-19.

The epidemiologic data coming from the Australian Department of Health Influenza Report indicates that this is going to be an influenza season like no other in modern history. What is so remarkable is that there is hardly any influenza this year. This graph shows the number of influenza cases over the past 6 seasons in Australia with the current influenza season in red and last year’s season in dotted green. Up until late March, the 2020 Australian influenza season appeared to be almost identical to last season. But then the number of influenza cases plummeted and there has been very few cases of influenza in April, May, and June.

It is still early to be sure since the peak of influenza in Australia normally occurs in August and September. But the early indication is that this is going to be one of the lightest influenza seasons on record in Australia and if so, then history tells us that the U.S. could have a light influenza season, also.

However, for this to happen, the U.S. will need to keep up social distancing and hand hygiene. As schools re-open in the fall and as workers return to their jobs, it may be very difficult for us to maintain our public health momentum next winter. So, this year Australian influenza epidemiology may not predict U.S. influenza epidemiology. Nevertheless, the information indicates that influenza can be controlled the same way that COVID-19 is controlled: staying home when you’re sick, washing your hands regularly, and avoiding those people who are sick.

But all Americans still need to get a flu shot this fall.

June 24, 2020

Categories
Epidemiology

When It Comes To COVID-19, Are We Testing The Right Thing?

During this COVID-19 outbreak, I have the dual roles of overseeing our hospital’s response to the pandemic and also of rounding in our ICU and taking care of COVID patients first-hand. One of issues that I struggle with in both of these roles is how accurate is our testing? Currently, we have 3 ways that we test for active COVID-19 infection: a nasopharyngeal swab for a rapid molecular test (made by Abbott Corporation), a nasopharyngeal swab for a PCR (polymerase chain reaction) test, and bronchoalveolar lavage fluid for a PCR test. We use the first two a lot and use the last one rarely. But do we have this backward?

The rapid molecular test by Abbott is very quick and our lab can have the results in < 1 hour. The criticism of this test is that it is less sensitive than the PCR tests so you can miss patients who are infected with COVID-19, particularly if they have mild symptoms or are asymptomatic.

The nasopharyngeal PCR test is currently considered the “gold standard” test for COVID-19. It appears to be more sensitive than the Abbott rapid test so it pick up more patients infected with the virus. However, it takes longer – 8-12 hours if your hospital does testing for it in-house and 2-3 days if it has to be sent to an outside lab. We primarily use this test if the Abbott rapid test is negative and we still clinically suspect COVID infection or if a patient without symptoms needs to be cleared of having the infection prior to undergoing an elective surgery.

The bronchoalveolar lavage (BAL) PCR test requires the patient to undergo bronchoscopy, an invasive procedure that requires sedating the patient and can put hospital staff at risk due to aerosolizing infected lung fluids into the air. Doing bronchoscopy on patients with suspected COVID-19 infection is generally discouraged because of the risk to the staff and the risk to the patient of an invasive procedure. Therefore, we don’t do a lot of BAL COVID tests.

Most respiratory viruses affect either the upper respiratory tract alone or both the upper and lower respiratory tract. The upper respiratory tract consists of the nose and throat; the lower respiratory tract consists of the lungs. COVID-19 is unusual among respiratory viruses in that it primarily causes symptoms in the lower respiratory tract resulting in cough, low oxygen, and shortness of breath. COVID generally does not cause much upper respiratory tract symptoms, such as sneezing or a runny nose.

So one has to wonder, if COVID does not affect the upper respiratory tract, how good is testing nasopharyngeal secretions?  Most of us who care for patients with COVID infection have encountered patients who had 1 or more nasopharyngeal Abbott rapid tests or PCR tests that were negative only to have the 2nd or 3rd PCR test end up being positive. We are also now seeing patients who have multiple negative nasopharyngeal PCR tests who then get a bronchoscopy and their BAL COVID PCR test comes back positive.

We spend a lot of energy debating whether the nasopharyngeal Abbott rapid or the PCR test is the best test. But maybe we ought to be asking whether the BAL is really the best test. When asked why he robbed banks, Willie Sutton famously said “Because that’s where the money is”. For those patients who present to the hospital with COVID-like signs & symptoms but have a negative nasopharyngeal PCR test, we may need to start doing more bronchoscopies with BAL COVID testing before pronouncing those patients virus-free.

May 17, 2020