The past two flu seasons have been mild ones, with very little virus circulating. Because of that, people’s immune systems may be more susceptible to the influenza virus, particularly younger children who may have previously had little or no exposure to the virus. (For more about waning immunity, read my last blog post.) Given these recent mild seasons during the pandemic, public health experts have been concerned that a severe flu season is on the horizon. Further, if it’s also circulating while COVID-19 cases are elevated, it could cause an added burden to our healthcare system. Based on the southern hemisphere’s flu season this year, public health experts are anticipating a moderate to severe flu season for the U.S. and northern hemisphere.
When is flu season?
The flu is a common virus that typically circulates in the winter. The critical prevention method is the flu vaccine, which is now available in the U.S. Traditionally, flu season in the U.S. begins in October and runs through as late as May – with the typical peak between December-February1 (although, as mentioned in my previous blog post, this past season extended into June). To get an idea of what could potentially be in store for the northern hemisphere’s flu season, public health officials monitor the flu season in the southern hemisphere. At GOJO, we watch Australia, which is renowned for its robust influenza surveillance.
How is Australia’s flu season going?
Australia’s flu season typically runs from April through October and peaks in August.2 This year, however, Australia saw an early start and early peak to their flu season, with cases peaking in May and June at the highest level they’ve been in 5 years. From mid-April through mid-July, the number of laboratory-confirmed influenza cases soared above the 5-year average, according to Australia’s Department of Health and Aged Care. Children aged 5-9 years old were the hardest hit, followed by children under 5 years, and people aged 10-19 years old. Influenza A was the predominant strain, which typically causes more severe illness and higher hospitalization rates. Indeed, Australia’s hospitalization rates were above its 5-year average from mid-April through June.
Many Australian hospitals were strained in July and early August due to high COVID-19 cases from the highly contagious Omicron BA.4 and BA.5 strains combined with the tail end of influenza cases as well as RSV cases (another virus that traditionally circulates during winter months and particularly affects children).3 Compounding the issue was that healthcare workers were getting sick with COVID-19.
Why should we be concerned about the flu?
Influenza is one of the most common infectious diseases. According to a CDC study, between 3%-11% of the U.S. population gets sick from the flu each year. The 2019-2020 flu season caused an estimated 35 million flu-related illnesses, 16 million flu-related medical visits, 380,000 flu-related hospitalizations, and 20,000 flu-related deaths, according to the CDC. It also costs an estimated $11.2 billion in direct and indirect costs to businesses in the U.S. annually, according to the National Foundation for Infectious Diseases.
What is in store for the U.S. this flu season?
There’s no way to know for sure what the upcoming flu season will be like, which is why we look to Australia and other southern hemisphere countries to glean any insights from what they experience. Given that Australia saw its highest flu season in 5 years, many thought leaders are concerned there is potential for a severe season in the U.S., with a particular potential impact on younger children, based on Australia’s higher level of cases in children 9 years and younger. They had an early start to their flu season too, with a quick and high spike in cases. If the flu season begins early in the U.S., it will have more time to infect people.
What are thought leaders saying?
- “There’s absolutely no doubt we’re in for a big season,” Ian Barr, deputy director of the World Health Organization Collaborating Centre for Reference and Research on Influenza, told Bloomberg. Australia’s Early Flu Season Shows Americans Need Their Shots - Bloomberg
- "There are a lot of young kids who have not had flu at all over the past couple of years," Dr. James Cutrell, an infectious disease expert at UT Southwestern Medical Center in Dallas, said in an NBC News piece. "That's going to make them more susceptible to getting it and then to spreading it to other people." He said that people shouldn't panic about the coming flu season but that “it is time for people to prepare." Australia’s bad flu season is a warning for the U.S. this year - NBC News
- “The Australian experience is suggestive that this could be a really bad flu season in the Northern Hemisphere as well,” Dr. Dean Blumberg, the chief of pediatric infectious diseases at the University of California Davis Children’s Hospital, told Healthline. When is the Best Time to Get a Flu Shot This Year? - Healthline
- "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," Leana Wen, an emergency doctor and public health policy professor at George Washington University, said in a WebMD article. "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." Is Australia's COVID, Flu ‘Twindemic’ A Warning for the U.S.? - WebMD
- “The early nature of the flu season in Australia is important,” explains Andy Pekosz, Ph.D., a virologist at the Johns Hopkins Bloomberg School of Public Health in the same WebMD article. “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.” Is Australia's COVID, Flu ‘Twindemic’ A Warning for the U.S.? - WebMD
Will a severe flu season impact hospitals?
A large concern is the impact a severe flu season could have on the healthcare system if COVID-19 hospitalization rates are high when flu hospitalization rates begin to rise. That combination – on top of other winter illnesses like RSV that can cause hospitalizations – could cause a severe strain on the healthcare system. Australia saw a strain on its healthcare system, given the concurrent circulation of COVID-19 (BA.4 and BA.5 strains) with flu and RSV. However, data would indicate that the U.S. already passed its Omicron wave, but as we have seen over the past two years another wave has quickly followed.
Will other illnesses be back this winter?
It’s likely we’ll see the typical winter respiratory viruses like RSV and bronchitis again, given the drop in pandemic precautions and other variables mentioned in my past blog post. Additionally, the U.S. again saw off-season summer RSV cases this year for the second summer in a row.4,5
How should I prepare for flu season?
It’s time to prepare for the flu season – an essential preventative step is to schedule your flu shot (it can help prevent severe illness and complications). Stay tuned for future blog posts by GOJO scientists offering tips to help you prepare your home and business for the upcoming flu and winter germ season.
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This is the third post in a series that GOJO scientists and clinicians are doing to help you and your business prepare for germs that will be circulating this winter. If you missed them go back and read my post "Are Viruses Behaving Strangely, or Are We?" and "5 Tips to Avoid Back-to-School Illness Outbreaks This Fall" by my colleague. Please subscribe to the GOJO blog to be notified when a new blog posts so you don’t miss upcoming posts in this series. In the meantime, visit the PURELL Well-Being Center for helpful information like when to wash or sanitize your hands, where germs are hiding, and where to place surface and hand hygiene products in your business to show your customers and employees you care.
Read these other GOJO blogs about surface hygiene from our scientists:
Do’s and Don’ts for a Worry-Free Clean
What’s the Difference Between Cleaning, Sanitizing, and Disinfecting?