It is summer in North America and that means that it is winter in Australia. Normally, Australia’s winter influenza season predicts how influenza will behave in the United States 6 months from now. But something very weird is happening in Australia this year – Australians are not getting influenza. So, what does this mean for the U.S.?
Last winter was a pretty average influenza season in the United States. Data from the CDC indicates that somewhere between 32 and 57 million Americans had an influenza infection last year. The statistics are always listed as an estimated range because not everyone who gets influenza gets tested. The CDC’s estimates are based on a mathematical model based on the CDC’s weekly influenza surveillance data. It is estimated that there were between 24,000 and 81,000 U.S. deaths from influenza last year.
Compared to previous years, this was fairly average. In most winters, between 25,000 and 50,000 Americans die from influenza. Once again, because not everyone who dies in the winter gets tested for influenza, the CDC reports annual influenza deaths as a range between what is the statistical 95% lower confidence level and 95% upper confidence level, as shown in the graph below.
Because the southern hemisphere experiences the annual influenza season 6 months before the northern hemisphere, the data from the Australian Centre for Disease Control often provides a preview of what the United States will experience in its winter. The graph below shows the number of laboratory confirmed cases of influenza in Australia for the past 4 years. Data from 2026 through June 14th is shown in the dark blue dashed line. Normally, cases of influenza in Australia peak in June or July. But so far this year, cases of influenza have been steadily falling since January and in fact are lower than the usual number of cases in Australia’s summer.
Australian COVID infections are also lower this year
Similar to influenza, the number of reported COVID infections in Australia this year is lower than in past years. The graph below shows that Australia is not experiencing a peak in COVID infections during the current Australian winter, unlike the past three years.
Australian RSV infections remain average
Unlike the remarkably low number of influenza cases in Australia this year, there is a fairly typical number of RSV infections. The graph below shows the number of reported RSV infections in Australia for the past 4 years. Data from 2026 is in the dark blue dashed line. Although there are fewer cases of RSV this year compared to previous years, the trend in seasonal RSV infections looks typical, with a rising number of cases as winter progresses and a likely peak within the next month.
Australian respiratory hospitalizations are mostly due to RSV this year
Surprisingly, the number of patients admitted to the hospital with influenza has been dropping since the Australian summer (January 2026). The graph below shows that RSV (green bars) currently accounts for far more hospitalizations than either influenza (blue bars) or COVID (black bars).
Australian influenza test positivity percentage remains low
Public health authorities track the percentage of influenza tests that are positive. Test positivity is similarly tracked for COVID and RSV tests. This is considered to be an early indicator of an upcoming spike in infections – when the test positivity percentage begins to rise, the number of cases of that particular respiratory virus can be expected to rise within the next 2-3 weeks.
So far this year, the influenza test positivity in Australia has been very low (blue bars in the graph below). COVID test positivity has remained fairly constant so far this year (black bars) but RSV test positivity has been increasing (green bars).
Why are Australia’s influenza numbers so low?
Epidemiology is 2 parts science and 1 part art. We usually do not fully understand a disease outbreak until after the outbreak is over and public health epidemiologists have had a chance to fully study both the rise and the fall in cases. So, we probably will not fully understand why the number of Australian influenza infections are so low this winter for another year or two. Nevertheless, there are some preliminary suspects as to the reasons why.
- Last year was a particularly bad influenza season. 2025 was the worst year for influenza in Australia this century. The number of reported cases was the highest ever recorded since Australia began tracking influenza in 2001. Australia also recorded 1,701 influenza deaths last year; prior to that the highest number of influenza deaths was 1,276 in 2017. The result was that Australians who survived the 2025 influenza season had good immunity against influenza in the way of antibodies developed from infections. These antibodies can then provide immunity against influenza the following year, particularly if the circulating strains of influenza are similar.
- Good effectiveness of this year’s influenza vaccine. Each spring, public health epidemiologists predict which strains of influenza will most likely circulate the following winter. This is not an exact science and the vaccines do not always end up protecting optimally against the influenza strains that actually show up in circulation. In Australia this year, the 2026 vaccine is turning out to be a particularly good match against the influenza strains that are in circulation. So far, 100% of influenza A(H1N1) isolates, 81.8% of influenza A(H3N2) and 87.0% of influenza B/Victoria lineage isolates are antigenically similar to this year’s vaccine components.
- An unusually warm Australian winter. 2026 is turning out to be an exceptionally warm winter in Australia. Sydney has had its warmest winter on record and the southeastern Australian states have had June temperatures 9℉ hotter than average. Warm temperatures mean that more people will be outdoors, rather than crowded together indoors. This results in natural social distancing that retards the spread of influenza.
What does this mean for next winter’s U.S. influenza season?
If history holds, then next winter could be a mild influenza season. However, there are notable differences in influenza recently between Australia and the U.S. First, whereas the previous influenza season in Australia was unusually bad, it was fairly average in the U.S. so Americans may be going into the flu season with less antibody protection than Australians have during their current winter. Second, there is no guarantee that the influenza vaccines for next season will match up to the influenza isolates that actually show up in circulation in the U.S. next winter – Australia may simply have gotten lucky this year with an unusually good vaccine match. Third, the U.S. may not have the unusually warm winter that Australia is having – the new El Niño weather event will likely bring warmer than average temperatures to the northern U.S. but colder than normal temperatures to the southern U.S.
The best virus defense is prevention
There are steps that Americans can take that will give us an edge against influenza this season. The single most important way to avoid getting infected by influenza is to not have close contact with anyone else with influenza. That means getting as many Americans vaccinated against influenza as possible and means implementing tactics to keep infected people away from uninfected people. Here are some specific tactics that we can implement to reduce influenza and other respiratory infections next winter:
- Increase influenza vaccination rates. Actually, the United States does a better job vaccinating its citizens against influenza than Australia. Last year, 46.5% of American adults and 49.3% of American children received an influenza vaccination. This year, only 26.2% of Australians received an influenza vaccination. When the person standing next to you in the grocery store checkout line gets a flu shot, then that person is not only less likely to get influenza themself but also less likely to give you an influenza infection. People who live in crowded living conditions should be particularly targeted for vaccination. George Washington realized this when he required his soldiers to be inoculated against smallpox, resulting in his army being healthy when the British army was impaired by a smallpox outbreak. The recent decision by the U.S. Secretary of War to not mandate influenza vaccination in the military is simply dumb.
- Facilitate work-from-home policies for sick employees. During the early years of COVID, the United States had historically low rates of influenza. One of the main reasons was that everyone who could was working from home and students were attending classes on-line in their own homes. The result was that a sick employee did not pass influenza on to everyone else in the office and a sick student did not infect the entire class. Employers and schools should create policies that allow sick employees to work from home when job requirements permit. Schools should also create policies that allow students to attend classes remotely when they get sick.
- Face masks work. To prevent getting infected by an airborne virus y0urself, you need to wear an N-95 grade face mask. But to prevent you from giving your influenza virus to someone else, your wearing of a simple medical mask will do the job. The anti-mask frenzy that overtook many Americans during the COVID pandemic reflected the ignorance of infection transmission that too many people had during those years. Employers should create work environments where the wearing of face masks by people with cold and flu symptoms who cannot work from home is encouraged or better yet, required. This means creating a workplace culture of face mask acceptance and preventing a workplace culture of face mask shaming.
- Improve RSV vaccination rates. Although COVID vaccinations and influenza vaccinations seem to get the most press, in Australia this year, there are far more hospitalizations for RSV than either COVID or influenza. That is unfortunate because the RSV vaccines are highly effective in preventing RSV infections. Healthcare providers should especially target pregnant women and people over age 65 to get vaccinated against RSV.
- Don’t forget about COVID. The COVID pandemic is a distant memory for most Americans. We’ve forgotten that 1.2 million Americans have died from COVID and that the United States had the highest COVID death rate in the world. Although COVID numbers are decreasing, it is still exceptionally deadly. Last year, about 40,000 Americans died from a COVID infection. Vaccination can save your life and save the lives of those people you are in contact with.
We will not know the full story of Australian influenza in 2026 for several months. But the data for the first half of the year is encouraging and hopefully portends a mild influenza season in the United States next winter. However, influenza always has the last word, so we should not let our guard down prematurely.
June 26, 2026
