Is Australia’s COVID, Flu ‘Twindemic’ A Warning for the U.S.?


July 20, 2022 – An alarming spike in COVID-19 and flu cases in Australia could put the U.S. on track for what health experts call a “twindemic” – a dangerous viral one-two punch in the months ahead.

It’s now winter in Australia, which is often a harbinger for the U.S. flu season. That country is having a massive wave of flu cases that have eclipsed pre-pandemic rates. Since mid-April, the island nation’s weekly number of confirmed cases has exceeded its 5-year average.

At the same time, Aussie health officials report that COVID-19 cases are skyrocketing as Omicron variants (including the highly transmissible BA.5 strain) continue to spread across the country.

These troubling trends in the Southern Hemisphere – combined with falloffs in vaccination, masking, and social distancing in the U.S. – are raising fears that Americans may face a similar twindemic this fall and winter, with another major COVID-19 wave along with a bad flu season.

“We’ve been predicting that the U.S. could be hit with this twindemic of influenza and COVID for the last couple of years, but it did not materialize before, in large part because influenza was relatively under control,” says Leana Wen, MD, an emergency doctor and public health policy professor at George Washington University. “But now, with people returning to pre-pandemic normal [activities] and with less immunity to influenza because of the lack of recent infection, we could see that twindemic this year.”

William Schaffner, MD, a professor of infectious diseases at Vanderbilt University School of Medicine in Nashville, says he is deeply concerned that many Americans are getting what he calls “vaccine fatigue.” As a result, millions might forgo a flu shot or new COVID-19 mRNA vaccine boosters under development to target BA.5 and the Omicron variants – putting themselves at grave risk for both viral infections.“Once I heard, just a few days ago, about what is happening in Australia my concern for what might happen here this fall increased,” says Schaffner, medical director of the National Foundation for Infectious Diseases and the foundation’s liaison to the CDC’s Advisory Committee on Immunization Practices.
“We’ve had a falloff of the acceptance of the influenza vaccine. This fall, the anticipation is that we will have updated COVID vaccine boosters. And that’s great, but we’ll also have to persuade people to get their influenza vaccine, so they’ll have to roll up both sleeves. And this is not going to be easy.”
Australia: Troubling Preview for U.S.?Andy Pekosz, PhD, a virologist at the Johns Hopkins Bloomberg School of Public Health, has been tracking the flu and COVID-19 rates in Australia for months and says he is alarmed.He says three troubling features stand out:

  • The Australian flu season, which typically runs from June to September, started unusually early this year – in April – and has already peaked months ahead of what is typically seen.
  • A massive surge of cases – 187,431 infections and 113 deaths so far – suggests this year’s flu strains are circulating widely in the Southern Hemisphere and infecting people who have not built up natural or vaccine-acquired immunity. Since mid-April, the weekly number of cases has exceeded Australia’s average over the past 5 years.
  • Australian health officials are also seeing a new rise in COVID-19 cases largely due to the Omicron variants – with more than 47,000 new cases reported each day. That’s up 62% since February.
These three things add up to an alarming “perfect storm” of viral infections that offers a preview of what the U.S. may face this fall and winter, he says.“The early nature of the flu season in Australia is important,” Pekosz explains. “If there’s not a lot of immunity in the population, we often see influenza earlier in the flu season. This is one of the earliest seasons on record in Australia, so it may indicate that there’s a lot of people who are susceptible to influenza.”One thing health officials have yet to determine: How effective Australia’s flu shot formulations, which typically provide the basis for the U.S. vaccine, have been in fighting the flu there.
“We haven’t seen those numbers yet coming out of Australia, but they should be coming sometime soon,” Pekosz says. “It will be important to see how well the vaccine is matched to those flu strains that are circulating.”