Myth of the Day: I Don’t Need a Flu Shot
Wow — what a cornucopia of awesome replies to the poll I sent out last week! In soliciting your feedback, dear readers, it’s clear that you are hungry for information on aging, menopause, weight loss, gut health, nutrition, osteoporosis, brain health, dietary supplements, and memory loss — among other topics.
(In case you missed the poll, you can let me know what’s on your mind HERE!)
So now, thanks to you, I’ve got a TON of ideas for future blog posts. But first, let’s finish up my myth-busters series. (So far, I’ve covered psychotherapy, the COVID booster shot, hormone replacement therapy, medications for anxiety and depression, aging, and sex.)
Nothing says autumn like pumpkin spice lattes, candy corn, and confusion about the flu shot. So today I present you with a Q & A all about the flu.
Q: What exactly is the flu?
A: The “flu” is a respiratory illness caused by a virus called Influenza. Every year we get a few new flu variants on the scene 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 officially start?
A: In the U.S. the flu season generally 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 in flu trends around the country.
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 three major factors: 1) the virulence of the dominant strain of the influenza virus, 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? Is it the same people at highest risk for COVID?
A: Generally yes. 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 both viruses. 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: Is it possible for people to contract COVID and the flu together? And if so, how bad will that be?
A: Yes. And while we don’t have enough data to know exactly if and how much sicker patients will get if infected with both viruses, it stands to reason that infection with flu and coronavirus together would lead to worse clinical outcomes than either alone.
Q: How will doctors be able to tell the difference between COVID and the flu?
A: Testing. Because the viruses mimic each other (i.e., cough, fever, body aches, etc), diagnostic testing is important for symptomatic people. As you know, for COVID we have both rapid antigen (aka “contagiousness”) tests and PCR tests. A positive rapid/home COVID test not only means that you have COVID; it means you have that contagious levels of the virus in your nose. A negative home COVID test does not mean you don’t have COVID; it means that either 1) you don’t have high enough levels of the virus in your nose to flip the test and to infect other people OR 2) you have some other respiratory infection altogether.
A negative COVID PCR test, however, means that your illness is very unlikely to be COVID. Recall that the PCR test is very good at detecting even the tiniest amounts of virus — even before symptoms appear — and can remain positive for many weeks after the acute illness because it picks up fragments of “dead” virus.
As for flu testing, currently we only have a PCR test which, for better or worse, has to be done in a lab. Home testing for flu doesn’t yet exist but is in the pipeline.
Q: Are there medicines available to treat the flu? And is it treated differently than COVID?
A: Oseltamivir (aka “Tamiflu”) and the newer Baloxavir (aka “Xofluza”) are prescription antiviral medications that target influenza. Paxlovid is the oral antiviral medication that I recommend to patients who are at higher risk for serious COVID outcomes when they get COVID.
These medications work by halting replication of the virus and work best when started early on in the course of infection.
In general, we treat COVID and flu with rest, aggressive hydration (with Pedialyte, for example), Ibuprofen or Acetaminophen for fever and aches, and, of course, time.
Q: So do you need to bring your kid to the pediatrician’s office — or you to your doctor — with every runny nose?
A: Great question. Testing is most important for the cohort of patients for whom a positive test would change medical management. In other words, I need to know if my 80-year-old patient’s cough and body aches are due to COVID, the flu, or something else in order to consider prescribing Tamiflu for the flu — or Paxlovid or monoclonal antibodies for COVID.
For your average healthy young person, however, testing isn’t as critical because the risk-benefit ratio of antiviral medications is different.
In general, I’m more likely to recommend Tamiflu for healthy young patients with flu than I am Paxlovid for healthy, vaccinated patients with COVID given the safety and efficacy data on Tamiflu — and given the absence of clear data showing that Paxlovid adds much value in vaccinated people, particularly under the age of 65. But this could of course change!
In order to protect members of the household from any respiratory virus, we also recommend isolating from others (if possible) until the person is improving and is fever-free for at least 24 hours without fever reducing medications.
I do still recommend patients with COVID to isolate until their rapid test turns negative (meaning: they are no longer contagious), so this is another use of home testing. For better or worse, we cannot be as precise in knowing when someone with the flu is no longer contagious, so we use the good old 24-hour fever-free rule above.
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 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.
Q: How important is getting a flu vaccine this year?
A: Very. We gauge the upcoming severity of the U.S. flu season by how it’s going in the Southern Hemisphere. And they’ve had a particularly bad flu season. Plus, because we haven’t had much flu over the last two seasons, our population immunity (that is, the combination of vaccine-induced and natural infection-acquired immunity) is thinner than usual.
The vaccine is our most powerful tool against the flu. Similar to the COVID shots, the flu shot doesn’t block infection, but it takes the claws and fangs away from the virus, reducing the risk for serious disease. Vaccination is important for kids, too. In a given year, the vast majority of children who die from influenza are unvaccinated. This year as we circulate more “normally” with other people, indoors and in closed spaces, it is especially critical to get your flu shot.
Q: Are flu and COVID spread in the same or different ways?
A: Both viruses are predominantly spread person-to-person and in the air. Flu is thought to spread more by larger air-borne particles (“droplets”) and coronavirus by smaller particles called aerosols. Therefore some of the interventions we’ve employed to decrease the spread of COVID have also decreased the spread of flu.
Q: Does getting the flu in the past protect people from getting it again?
A: Getting sick and surviving the flu once won't necessarily prevent illness with another strain that is different enough from the one you had in the past. There is some cross-reacting protection, though. People who survived the 1918 flu and are still living, for example, still have active antibodies to that strain. Natural immunity to flu isn’t as durable because influenza doesn’t stimulate the immune system (specifically the T cell response) very well — and certainly not as well as COVID itself or the COVID vaccines do to prevent reinfection or breakthroughs. Each flu shot does confer somewhat additive immunity, but because the strains vary year to year, we need to switch up the vaccine to stimulate production of the appropriate antibodies to fight that particular strain in circulation.
Q: When should people get the flu shot?
A: Now! The more sophisticated answer is: 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 the shot. So get it this week if you can!
Q: Should I separate the flu shot from my COVID shot?
A: No need! The CDC and AAP agree that you can get the flu and COVID shots the same day.
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.
Flublok is three times the strength of the regular flu shot, is quadrivalent, and can be given to any patients ages 18 and up who are immunocompromised or need additional protection. It can also be considered for patients 65 and older who had moderate-severe reaction to HD flu.
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: But why should I get the vaccine if it’s only 20% to 60% effective?
A: Because the flu shot will blunt the effects of the virus and reduce your likelihood of infecting others. Let’s not make the perfect the enemy of the great.
Q: But, but, but … I don’t like shots. Waaaah!!
A: Aside from the last two years, every fall and winter I treat many unvaccinated patients for the flu. I can’t think of a single flu patient who — without my prompting — hasn’t vowed to forever get the flu shot going forward! Flu is a nasty bug and can take you down for a week or two. The vaccine is our best weapon against it. It’s also something we can actually control in these uncertain times.
For more info, find me on Tuesday for my weekly Q & A on Instagram where you drop your questions into the box for me to answer the next day.
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Speaking of weapons and uncertainty, I’m thrilled to welcome Shannon Watts, the founder of the largest gun violence prevention organization in the U.S., Moms Demand Action, on this week’s episode of Beyond the Prescription.
Shannon and I talk about the 2012 Newtown Connecticut massacre that prompted the founding of her organization, the trauma of everyday gun violence in America, and what it's like to be targeted as the face of the gun control movement.
As always, my newsletter subscribers get early access to the pod every Monday night before the official Tuesday launch. Give it a listen now on Apple, Spotify, or wherever you find podcasts. And I’d be TICKLED PINK if you could rate and review the show. It helps me a ton!
I will see you next week. Until then, be well.