Update on The Flu & Flu Vaccines
Your guide to the 2023-2024 Influenza season
Disclaimer: The views expressed here are entirely my own. They do not reflect those of my employer, nor are they a substitute for advice from your personal physician.
Q: What exactly is the “flu”?
A: The “flu” is a respiratory illness caused by the Influenza virus. Every year we get a few new flu variants that cause symptoms like cough, sore throat, fever, body aches, headache, and fatigue. Flu can cause pneumonia and other, more severe symptoms. It can also be fatal.
Q: When does flu season start?
A: In the U.S. it usually starts in October and lasts until early spring, with a big uptick in December, depending on geography. The CDC has a nice tracker if you’re interested.
Q: How many people die from the flu every year?
A: The CDC estimates that, depending on the season, approximately 12,000 to 60,000 people die from influenza every year in the U.S. The actual mortality data for each season hinges on 1) the virulence of the dominant flu strain, 2) the effectiveness of the vaccine that year, and 3) the proportion of the population that actually takes the vaccine.
Q: Who is at highest risk for flu?
A: While anyone can get the flu, people over age 65 or who have immune deficiencies or underlying conditions like diabetes or obesity or immune deficiencies are at higher risk for serious outcomes from the flu. Kids ages 0-5 years old—especially those under 2 years—are at higher risk compared to older kids for developing serious flu-related complications, in part due to their small airways.
Q: How does the flu spread?
A: It spreads predominantly person-to-person and in the air. It is more likely to spread in crowded, indoor environments with poor ventilation.
Q: How effective is the flu shot?
A: The effectiveness of the flu vaccine against infection varies from 20% to 60% depending on the year. It’s important to know that even when the flu vaccine effectiveness is low, it can have a major impact on morbidity and mortality. For example, despite a mere 29% effectiveness of the flu vaccine against infection in the 2018-2019 flu season, the CDC estimates that the vaccine prevented 3500 deaths. In other words, although the flu vaccine may not prevent you from contracting the flu, if you are vaccinated, you are much less likely to be hospitalized or die from the flu.
Note that a universal flu shot, one that could protect against multiple strains, regardless of annual mutations, is on the horizon!
Q: How important is getting a flu vaccine this year?
A: Very. The vaccine is our most powerful tool against the flu; it takes the claws and fangs away from the virus, reducing the risk for serious disease and infecting others.
Q: When should I get the flu shot?
A: September or October is ideal. Why? You want the shot ideally two weeks before the virus starts circulating in your community, because it takes about two weeks for your immune system to fully respond to it.
Q: Which flu shot should I get?
A: The standard flu shot is “quadrivalent,” meaning that it covers four strains of the flu and can be given to anyone ages 6 months and older. The high-dose (HD) flu shot is four times the strength of the standard flu shot, is also quadrivalent, and is appropriate for patients age 65 and above, especially those with chronic disease.
Q: Can I get the flu, COVID, and RSV shots on the same day? Or is it better to separate?
A: While it is technically safe to get the COVID, RSV and flu shots together, I suggest my patients separate them by at least one week to be uber cautious because the side effects can be more pronounced if they are taken together. As for flu and RSV shots, a few of the participants in the clinical trials for the RSV vaccines found had severe side effects when they got the flu vaccine on the same day.
Q: Should I get two flu shots this year, one in fall and one in early 2023 as a booster?
A: Currently there is no recommendation from the CDC or other expert group on giving two flu vaccines this year, but this can be an individual discussion with your doctor. For now, the main focus should be getting one dose this fall.
Q: Do I still need a flu shot if I a) “never” get sick or b) “only got the flu when I got the flu shot”?
A: Yes! Similar to the COVID vaccines, the flu shot not only protects you from serious disease; it can reduce (but not fully block) the risk of infecting others. The flu shot cannot cause the flu. But it can cause transient flu-like symptoms (muscle aches, low-grade fever) that signal your body getting ready for the real thing. I promise you: the flu is a whole lot worse than the potential side effects from the flu shot!
Q: Are there medicines available to treat the flu?
A: Oseltamivir (aka “Tamiflu”) and the newer Baloxavir (aka “Xofluza”) are prescription antiviral medications that target influenza, however data show that their efficacy is becoming weaker and weaker.
In general, we treat respiratory viruses with rest, aggressive hydration (with Pedialyte, for example), Ibuprofen or Acetaminophen for fever and aches, and, of course, time.
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