The flu has already started spreading in the Houston area. This earlier-than-usual start to the season, coupled with high case numbers in the Southern Hemisphere, are indicators that this year’s flu season may be a rough one, public health experts warn. The flu vaccine is our best defense: It prevents millions of illnesses every year, according to the U.S. Centers for Disease Control and Prevention, and it can mitigate the danger to people at high risk for complications, including pregnant people, infants, older people and those with a weakened immune system.
Dr. Luis Ostrosky, the medical director for epidemiology and antimicrobial stewardship for Memorial Hermann-Texas Medical Center and UT Physicians, shared his insights about this year’s flu season and the best time to get your shot.
Q: When should people get a flu shot?
Dr. Ostrosky: We normally recommend getting your flu shot in the fall, and often we recommend doing it in October to make sure it’ll last through the whole winter season. But we’re already seeing signs of flu activity in Houston, so we’re recommending people get them starting now. As soon as we start seeing cases, we want to take care of that immediately.
Q: How long does immunity typically last?
Dr. Ostrosky: For flu shots, it’s usually about four to five months. We think it’s about the same for the COVID boosters, based on what we know now, but we’re still learning about those boosters. It may not be all about antibodies — there may be other parts of your immune system that are being trained that we can’t measure currently. That’s true for the flu shot, too: Even if you no longer have antibodies, your T-cells and other parts of your immune system would still have some protection.
Q: How effective are flu shots?
Dr. Ostrosky: We make our best guess every year about what the strains are going to be in circulation. It’s a calculated guess based on what’s happening in the Southern Hemisphere, where they already had their flu season. In a bad year, we’ll see about 30 percent efficacy. In a good year, we might see 60 to 80 percent efficacy. But even if it doesn’t stop you from getting the flu, it will be milder if you’ve gotten a flu shot.
Q: Why do epidemiologists suspect this year will be worse than usual?
Dr. Ostrosky: We’re already seeing a number of cases in the community, and this is very early in the season, so that’s a bad omen. If we look at Australia, which is kind of our canary in the coal mine, they had a really difficult and aggressive flu season this year. So we’re expecting a rough flu season here as well.
Q: What makes one season worse than another?
Dr. Ostrosky: It’s a combination of the particular strains of the flu that are circulating, and, in this case, other causes that are more geopolitical. There’s currently a lot of mistrust in vaccines, and if fewer people are vaccinated, you’ll have a worse season. We’ve also had a global pandemic for the past few years, and people missed a lot of vaccines during that time, which has a cumulative effect. Each year that you miss a vaccine, you miss an opportunity to build immunity to different strains.
Q: Is there any reason to stagger the flu shot and the COVID booster?
Dr. Ostrosky: The CDC is telling us you can get them both at the same time, in different arms. You’re not more likely to experience adverse effects by getting both together, so it makes sense to do one-stop shopping and get both at once. We are going to recommend in the future that people get both shots at the same time, on a yearly basis.
Q: Is there anyone who shouldn’t get a flu shot?
Dr. Ostrosky: We recommend that everybody get it unless you’re allergic specifically to the flu shot, which is very rare. For people with egg allergies, we have an egg-free flu shot that’s regularly available. And for people over 65, we have what we call the high-dose flu shot, which is known to increase antibody production for people who are elderly and might not respond as well to the standard shot.
Q: What are some reasons people give for not wanting a flu shot?
Dr. Ostrosky: The No. 1 reason I hear is: “I got the flu shot and I got the flu anyway.” Or: “the flu shot gave me the flu.” The flu shot doesn’t contain any live virus, so there’s no way it can give you the flu. You can, however, catch the flu in the community if you didn’t get the shot early enough. It takes two weeks after you get the shot to build immunity, just like with the COVID booster. Another one I’ve heard is: “I got the flu shot and felt horrible afterward.” There are some mild side effects from the flu vaccine, which can include fever, muscle aches and headache. But they’re much milder than if you actually got the flu.
Besides protecting yourself, there are other reasons to get the vaccine. If you have vulnerable people in your house, you want to get this shot sooner rather than later. You’re not just protecting yourself – you’re protecting them.
For more information about flu shots, visit: www.memorialhermann.org/services/specialties/primary-care/flu