It is the start of the 2024 Christmas holidays and COVID is on the upswing for its annual winter surge. With 5 years of COVID data, we know a lot about its epidemiology and that allows us to predict what will happen over the next month. Unlike other seasonal respiratory viruses, COVID has had two peaks in case numbers every year – one peak in the summer and another peak in the winter. These twice yearly peaks are illustrated in the graph below showing COVID deaths by week since the onset of the pandemic in 2020.
In the first year of COVID, the best way to track it was case numbers, identified by testing for the virus. Today, case numbers are no longer very useful because many people with COVID either test themselves at home or do not get tested due to relatively mild symptoms – health departments are unable to track these cases. Instead, epidemiologists now rely on other data to track COVID including COVID deaths, virus concentrations in wastewater, the percentage of ER visits diagnosed as COVID, and the percentage of COVID tests reported to health departments that were positive for COVID. Because COVID deaths occur days or weeks after initial infection, death rates do not give physicians real-time information on the number of people infected with COVID at any given time. Consequently, wastewater viral loads, percent positivity of tests, and percent of ER visits give better information about current infections. The graphs below illustrate the temporal relationship between COVID deaths (blue bars) and the percentage of ER visits diagnosed as COVID (gold line, top graph) and the percentage of COVID tests reported to health departments that were positive (gold line, bottom graph).
From these graphs, we can see that COVID is currently on the rise in the U.S., just as it has been in early winter since 2020. The CDC has been tracking the viral load in sewer wastewater since 2022. Like % test positivity and % ER visits, the amount of COVID virus in wastewater is an early indicator of COVID and is also currently on the rise in the U.S.
From these data, the winter COVID surge is already starting and will likely peak next month, in January. So, what can we expect from this winter’s surge? From previous years’ data, we can predict the demographics of those who will become severely ill and those who will die next month.
Predicting the demographics of this season’s COVID surge
In the first two years of the pandemic, COVID was much less discriminating than today. Although older persons were more likely to become severely ill or die, anyone could get infected. Younger people, particularly those with diabetes or obesity, were also at risk of death. Today, things are different. Most Americans have some degree of immunity, either from vaccination or from surviving previous infections. Consequently, the COVID demographics have changed. Let’s take a look at what we can expect this winter.
Age is still the greatest risk for death. In the first year of the pandemic, it was notable that children rarely died of COVID infection, relative to adults. This trend has continued and the most recent COVID surges have shown that the overwhelming number of people hospitalized or dying from COVID are older adults, particularly those older than age 75. The graph below shows death rates by age since the beginning of the pandemic with the insert showing an enlarged portion of the graph for last summer’s surge. Most of those who will die this winter will be over age 75 (solid brown line) with a smaller death rate for those between 65 – 74 (dashed pink line). The overall death rate for all ages is the dashed blue line). Those younger than 65 will have a very low death rate.
Men will be still more likely to die than women. In the early years of the pandemic, the COVID death rate for men was about 25% greater than the death rate for women. Although this gender effect is still present, it has lessened over the past year. Last summer, the death rate for men (gold line) was about 22% higher than for women (purple line) and last winter, the death rate for men was only about 8% higher than for women.
White Americans will have the highest death rate from COVID. In the first COVID surge in April 2020, Black Americans had the highest death rate, peaking at 39.17 per 100,000. In the December 2020 surge, Native Americans had the highest death rate at 50.41 per 100,000. In September 2021, Hawaiian Americans and Pacific Islanders had the highest death rate at 26.10 per 100,000. However, since January 2022, White Americans have consistently had the highest death rate from COVID. Conversely, throughout the pandemic, Asian Americans and Hispanic Americans have had the lowest death rates from COVID.
One of the reasons for the lower COVID death rates in Asian Americans and Hispanic Americans was the early adoption of COVID vaccination by these racial groups compared to White American and Black Americans. By September 30, 2022, fully 75% of Asian Americans had been vaccinated as opposed to only 45% of White Americans and 43% of Black Americans.
White Americans are increasingly more likely to be hospitalized. Early in the pandemic, Black Americans and Hispanic Americans were disproportionately more likely to be hospitalized with COVID than other U.S. racial/ethnic groups. However, since 2021, White Americans are increasingly more likely to be hospitalized than other racial/ethnic groups. The graph below shows the percentage of people hospitalized with COVID by race: White Americans are in blue, Black Americans are in light brown, Hispanic Americans are in dark brown, and Asian Americans are in green. Currently, 79.25% of hospitalized patients are White Americans. Given that White (non-Hispanic) Americans comprise only 58% of the population, it is clear that White Americans are disproportionately hospitalized compared to other U.S. racial and ethic groups.
Older Americans are increasingly more likely to be hospitalized than younger Americans. Early in the pandemic, more than half of Americans hospitalized with COVID were younger than age 65. Since 2022, this has changed with people older than 65-years-old accounting for an increasingly large majority of those hospitalized with COVID, as shown in the graph below. Currently, approximately 70% of hospitalized patients are older than 65 (red bars) with 15% of hospitalized patients between ages 50 – 64 (green bars), about 10% between ages 18 – 49 (blue bars), about 2% age 5 – 17 (brown bars), and 3% age 0 – 4 (purple bars). This is likely due to an overall increase in U.S. “herd immunity” with the result that now COVID preferentially preys on those who are older.
Influenza is catching up but more people will still die from COVID. Historically, influenza was the main seasonal virus causing death in the United States. Since the beginning of the pandemic, COVID has supplanted influenza. Data from last year’s winter respiratory virus season shows that influenza hospitalizations (blue line) are catching up with COVID hospitalizations (gold line). RSV (purple line) continued to be an important reason for hospitalization but only accounted for about half as many hospitalizations last winter as either COVID or influenza. The summer 2024 COVID surge was not accompanied by an increase in either influenza or RSV hospitalizations as is typical since influenza and RSV mainly occur in winter.
However, when it comes to death from respiratory infections, COVID still reigns king. The graph below shows the percentage of U.S. deaths due to COVID, influenza, and RSV. Looking at last winter’s respiratory virus surge, COVID (gold bars) accounted for far more deaths than influenza (blue bars). RSV (purple bars) was an uncommon cause of death. This is in keeping with a recent study published in JAMA showing that unvaccinated patients admitted with COVID were more likely to either die or require mechanical ventilation than unvaccinated patients admitted with either influenza or RSV. Patients who had been vaccinated for COVID who then were admitted with COVID infection were also more likely to die or require mechanical ventilation than patients vaccinated for influenza who were admitted with influenza infection. The bottom line is that we will likely see about the same (or more) patients admitted with influenza this winter as compared to COVID but the patients with COVID will be considerably more likely to die.
Is COVID ever going to go away? At the beginning of the pandemic, there was hope that COVID would act like the Spanish influenza pandemic of 1918 and fade away. By the winter of 1920 – 21, the influenza serotype responsible for the Spanish flu had essentially disappeared from the United States. However, after 4 years, COVID is still going strong. What has changed are the various serotypes of COVID that are responsible for the different seasonal surges. In this way, COVID is very similar to influenza, with each season’s surge caused by different serotypes due to constantly mutating virus. Similarly, like influenza, immunity to last year’s variant does not provide complete immunity to this year’s variant. And immunity wanes over time. Together, these two features of COVID immunity result in people being susceptible to infection every year and many Americans have had multiple episodes of COVID infection over the past 5 years. For these reasons, it is unlikely that COVID is going to go away in the foreseeable future. Perhaps the best that we can hope is that the summer surge eventually disappears and the winter surge more closely resembles influenza in terms of death rates.
So, what should hospitals do to prepare?
First, and most importantly, get as many patients vaccinated as possible. By now, it is very clear that vaccination does not prevent all infections but vaccination does help reduce the severity of infections so that vaccinated persons are less likely to require hospitalization or to die. Vaccinating the community with the most recent COVID vaccine will reduce hospital bed and ICU utilization. An effective way of getting the word out about vaccination is by messaging patients through the hospital’s electronic medical record, especially when the electronic messages come from patients’ primary care providers.
Second, be sure that hospital supplies of personal protective equipment and COVID tests are sufficient. This equipment includes eye protection, N-95 masks, gowns and gloves. Not only does the central hospital lab need to be fully stocked with COVID test reagents, but outpatient clinics should be stocked with point-of-care COVID test kits. Because of the overlap between influenza and COVID symptoms, point-of-care test kits that cover both influenza and COVID should be used instead of influenza-only and COVID-only test kits.
Third, because the prevalence of COVID will increase in January, hospitals should consider resuming day-of-surgery preoperative testing for COVID. Patients with COVID infection may be asymptomatic in the first couple of days of infection and infected patients are more likely to have postoperative complications. This is not only bad for the patients, but is also bad for the hospital since it can increase the cost of elective surgical admissions, thus eroding the DRG profit margin from surgeries. It is also bad for the individual surgeons who can have their surgical outcome statistics negatively affected.
Fourth, ensure that the hospital pharmacy is adequately stocked with dexamethasone, tocilizumab, baricitinib, and remdesivir for patients admitted with severe COVID infection. Because the number of influenza admissions will likely be similar to the number of COVID admissions, the hospital pharmacy should also be adequately stocked with Tamiflu.
Fifth, update hospital COVID inpatient treatment guidelines. The recommendations for managing hospitalized patients with COVID infection have evolved over the past 5 years. Be sure that the hospitalists and others who admit inpatients with COVID infection are up to date with the current recommendations for testing, isolation precautions, oxygen therapy, pharmacologic treatment, and other aspects of inpatient management.
Sixth, update COVID outpatient treatment guidelines. Because a very high percentage of primary care physicians are now hospital-employed, hospitals have the ability to standardize outpatient treatment within their provider networks. Hospitals should be sure that their evidence-based guidelines incorporate updated recommendations for testing and isolation as well as indications for treatment with nirmаtrеlvir/ritonavir (Paxlovid) and indications for hospitalization.
Don’t let your hospital suffer from COVID fatigue
Let’s face it, we are all sick and tired of COVID and it seems like life is back to normal again. You need a reservation again to get into top restaurants. Movie theaters are packed again. And at Thanksgiving, family dinner tables were full again. In the past two months, I’ve been on 12 different airline flights and on each, I was either the only person or one of only a small percentage of travelers wearing a face mask. But COVID has not gone away. Currently, 5,000 – 6,000 Americans are hospitalized each week and 400 – 500 Americans die each week from COVID. Historical trends indicate that these numbers will increase 4-fold to 5-fold over the next month. By making a few simple preparations today, our hospitals will be ready for the upcoming COVID winter surge.
December 23, 2024
