Infectious disease experts expect this flu season to be a rough one.
The Southern Hemisphere just wrapped up its worst flu season in years, signaling that the Northern Hemisphere may soon battle a severe flu season.
Texas, Georgia, and Washington DC are already seeing unusually high flu activityTrusted Source for this time of year.
The majority of flu cases this season have been caused by influenza A H3N2Trusted Source, a strain that’s previously been associated with severe flu seasonsTrusted Source.
While the flu shot appears to be a good match to the circulating strains, a recent survey found that nearly half of Americans don’t plan to get vaccinated against the flu this year.
What, exactly, this means for this year’s flu season has yet to be seen, but doctors suspect the country is ripe for flu to make a startling comeback.
Healthline asked four flu experts what to expect this influenza season. Here’s what they said.
Dr. Michael Chang, an infectious disease doctor at Memorial Hermann Health System in Houston, Texas
Dr. Susan Hassig, an epidemiologist and professor in the epidemiology department at Tulane University’s School of Public Health
Dr. Erica Johnson, an infectious diseases doctor who chairs the Infectious Disease Board of the American Board of Internal Medicine
Dr. Theodore Strange, a primary care physician and the Chair of Medicine at Staten Island University Hospital
Texas has high flu activity right now. What does that mean for the rest of the country?
Dr. Chang: Outpatient numbers of positive flu tests had started increasing a few weeks ago and has significantly ramped up in the last two weeks. This is earlier than typical to see a spike in flu cases. For Texas, we tend to see flu start to increase after the Thanksgiving holidays. It is too early to judge whether the cases are more severe so far though. It’s surprising since we have still had warm and/or fall weather, so most people aren’t thinking about the flu. Even for those planning to get vaccinated, many people haven’t received their seasonal influenza vaccination yet and so our region may be caught off guard. Unfortunately, many other parts of the country are likely to see their flu cases increase before people were planning to get vaccinated.
Dr. Strange: The influenza virus has been spreading around the United States for approximately a month or so. Texas and New York both have high flu activity likely from large population centers and large number of travelers. Having big states already with high activity likely portends to a very active and contagious flu season.
When are we likely to see spikes in flu activity?
Dr. Chang: It’s difficult to predict precisely for each part of the country, but it’s reasonable to think that as cold weather sets in we will see increases in flu cases and other respiratory viruses. However, everyone should be prepared for the flu season to start several weeks earlier than usual.
Dr. Strange: The season usually begins in October, spikes and peaks in between December to February and slowly declines as winter ends and spring begins.
Is this year’s flu shot a good match to the strains that are spreading (H3N2)?
Dr. Johnson: This year’s flu shot composition does include protection for an influenza A H3N2 strain, as well as an influenza A H1N1 strain and two types of influenza B. The decision to include this H3N2 strain was based on the fact that this one matched the strain that circulated predominantly in the US during last year’s flu season.
Dr. Hassig: So far it appears the current flu shot is matching well to the circulating virus in the US, but uptake of the flu vaccine is still lower than we would like to see, especially in older populations. Vaccine uptake this year is important because the dominant flu strain appears to be one that tends to cause more severe disease, and in the past has been responsible for the higher death rates we see in some flu seasons.
What can we learn from the Southern Hemisphere’s flu season?
Dr. Hassig: It was a bad (lots of severe disease) season in the southern hemisphere during their winter, and what they experience is often a good predictor of what will happen in the US.
Dr. Chang: The most recent Southern Hemisphere flu appeared to be “severe” flu season with more cases than several prior years. It appeared similar to, or even slightly worse than, the 2017-2018 season which was considered a high-severity season in the United States by the CDC. I anticipate we will see the same phenomenon here, especially as the flu season is starting earlier and many people haven’t been vaccinated yet.
Dr. Johnson: In the Southern Hemisphere, flu transmission generally occurs April to September, and this season, there was more flu activity in the Southern Hemisphere than in the prior two seasons. So it makes sense to be concerned that we may see more flu activity in the US this flu season as well.
Half of Americans don’t plan to get the flu shot. How could this impact flu activity this year?
Dr. Hassig: I am concerned that many Americans are not thinking about the threat that flu may pose in the US. Flu can cause severe disease and death in both the very young and the old.
Dr. Johnson: Not getting the flu vaccine may put that person at risk for more severe illness if they become infected with the influenza virus. And more severe flu illness can mean more lost days from work and school and more hospitalizations from complications of flu.
Dr. Strange: Not getting vaccinated increases the chances of spreading the disease and susceptibility of getting a more severe case of the illness and even death from the flu.