Your Guide to Fall/Winter Viruses & Vaccines

🦠 How to protect against flu, COVID & RSV 🦠

Dear newsletter readers, 

In response to your questions about the flu, COVID and RSV vaccines, I wrote a separate post for each virus—they deserve it!

Click below for a deep dive into prevention, testing, treatment, and the who, what, when and why for each virus:

Want the Cliff Notes instead?

Here’s the gist of what I’m recommending to my adult patients this fall:

• FLU: Everyone should get a seasonal flu shot in September or October.

• RSV: Consider the new RSV vaccine if you are over 60 and have underlying health conditions and/or a compromised immune system.

• COVID: Consider getting the new COVID booster when it comes out in late September/early October if:

  • You are over age 65. 

  • Your immune system is compromised.

  • You have underlying health issues like obesity, diabetes, or heart disease.

  • You haven’t had COVID in the last 2 months.

  • You haven’t had a COVID booster in the last 4 months.

  • You would like additional short-term protection against infection and additional longer-term protection against serious disease, and

  • The benefits of the vaccine outweigh the potential downsides (i.e., short-term side effects like fever and body aches; the rare but real risk of vaccine-associated myocarditis in teen and young adult males.)

Please bookmark, print, and share this widely!

Got more questions about flu, COVID and RSV? Submit them here for Friday’s Q&A!

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FAQs about fall/winter viruses:

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 had severe side effects when they got the flu vaccine on the same day. 

Photo by National Cancer Institute on Unsplash

Q: How can doctors tell the difference between COVID, RSV, and the flu?

A: Testing. Because the viruses mimic each other (i.e., cough, fever, body aches, etc), diagnostic testing can be important for symptomatic people. PCR tests exist for all three viruses. PCR tests detect the genetic material of the specific virus and are highly sensitive tests; i.e., rarely do we see false positive tests in actively sick people. 

Note that for COVID, we also have rapid antigen (aka “contagiousness”) tests. A positive rapid/home COVID test not only means that you have COVID; it means that you have 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 infect other people OR 2) you have some other respiratory infection altogether.

We don’t yet have home testing for flu and RSV, but hopefully we will soon!

Q: So do I need to bring my kids and myself to the doctor with every fever and 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, flu, RSV, or something else in order to consider prescribing Tamiflu for the flu—or Paxlovid for COVID.

But for your average healthy young person, testing isn’t as critical because the risk-benefit ratio of antiviral medications is different and because the chance of severe outcomes is low.

Q: What about isolation periods when sick this season?

In order to protect members of the household from any respiratory virus, I recommend isolating from others (if possible) until the person is improving and is fever-free for at least 24 hours without fever-reducing medications.

Q: Does masking help prevent spread?

A: One-way masking has been shown to protect the wearer; however, the data on masking asymptomatic people to help protect against community spread are weak. My advice is to wear a well-fitted, high-grade mask consistently if you want added protection against infection. For example, if a household member is sick, wearing a KF94 or KN95 mask might reduce your risk of infection.

Q: Does getting one of these viruses in the past protect me from getting the same virus again?

A: Getting sick with flu, COVID, or RSV won't necessarily prevent illness with another strain that is different enough from the one you had in the past; however, there is some cross-protection. For example, people who survived the 1918 flu (and are still living) still have active antibodies to that strain of flu! Post-infection immunity to flu is less durable than the nice immunity to COVID after an infection or vaccination. This is thanks to our T cells which are stimulated by COVID and the vaccine to help protect us against serious disease. Post-infection immunity to RSV is pretty wimpy. Most kids have had RSV by age two, and most people are reinfected with RSV multiple times in their lives, sometimes without even knowing it. 

Q: Other than vaccines, what can I do to protect myself against these viruses?

A: The best way to protect yourself against complications from any infectious disease is to take care of your underlying health. So schedule your check-up with your doctor, and do your best to prioritize sleep, nutritious eating, regular exercise, and time outside in nature.

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For deeper dives, click below!