Australia is currently experiencing an unusually early increase in flu cases—a development that may foreshadow the United States' experience in the fall, Lisa Jarvis writes for Bloomberg/Washington Post.

Now is the time to move the needle on flu vaccinations

How the pandemic has impacted America's flu seasons

According to Jarvis, the pandemic has significantly impacted flu season in the United States. During the first year of the pandemic, flu was virtually nonexistent as Covid-19 precautions, such as social distancing and mask wearing, cut down on viral transmission.

Then, in the 2021-2022 flu season, cases increased above the prior year, but remained far below pre-pandemic levels.

Flu cases also continue to be reported past the season's typical February peak. This year, the United States saw a late season peak in flu cases in mid-April—something that has not happened in decades, according to Lynnette Brammer, head of CDC's domestic influenza surveillance team. In addition, some parts of the country are still seeing last winter's influenza strain circulate. For the week ending June 10, CDC reported a 5.9% test positivity rate for flu, or 3,365 new flu cases.

"It is just wild that we sit here [in June] and still have substantial flu activity," said Scott Hensley, a professor at the University of Pennsylvania who studies influenza.

What does Australia's early flu season mean for the US?

Currently, Australia is experiencing an early increase in flu cases, concerning the country's public health authorities about a potentially more severe flu season. As of June 5, Australia's national disease surveillance system reported almost 88,000 flu cases—with more than half of them diagnosed in the last two weeks.

"There's absolutely no doubt we're in for a big season," said Ian Barr, deputy director of the World Health Organization's Collaborating Centre for Reference and Research and Influenza. So far, flu cases in Australia are following a pattern similar to its 2019 season, which was a record year for flu in the country.

Although flu activity in Australia and other Southern Hemisphere countries is not always an accurate predictor for what will happen in the United States, this early uptick in flu cases may be a warning of what could come in the fall, especially after two years of low flu activity.

In addition, flu vaccination rates in the United States have decreased over the last two years, particularly among vulnerable groups like children and pregnant individuals. Among children, flu vaccination rates have dropped from 62.2% to 55.3%, and among pregnant individuals, rates have dropped from 65.5% to 51.8%.

To prevent a severe flu season in the fall and winter, U.S. public health authorities need to boost vaccination rates, particularly through provider recommendations and other offerings.

"Companies should get back to providing vaccines at work, pediatricians' offices should consider how to ensure parents can get vaccinated along with their children, and school districts should work to increase rates of routine flu jabs in kids," Jarvis writes.

In addition to flu vaccines, Americans may also need another Covid-19 booster in the fall, particularly as omicron subvariants continue to circulate. According to Jarvis, health care facilities should have ample supplies of both vaccines to offer patients, and health officials will need to communicate with patients to let them know they can get be vaccinated against both flu and Covid-19 at the same time. (Jarvis, Bloomberg/Washington Post, 6/13; Australian Associated Press/The Guardian, 6/11)