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  • Writer's pictureP.K. Peterson

This Year’s Flu Shot: With or Without a COVID-19 Booster?

“Flu can be serious, and it kills tens of thousands of Americans each year. Vaccination is easier and more convenient than ever, so get yourself and your family protected.” - Tom Frieden, M.D., former Director, Center for Disease Control and Prevention

“Someone told me they didn’t want to take a flu shot because they didn’t want to put a foreign substance in their body. What do they think they do at dinner every night?” - Michael Specter, American journalist

The influenza season essentially disappeared in 2020-2021. According to the Center of Disease Control and Prevention (CDC), the U.S. saw only about 700 deaths from influenza in 2020-2021 with only one reported pediatric death. Compare this with 2019-2020 (a year of moderate flu activity) when an estimated 38 million Americans developed a flu-like illness and 22,000 deaths were attributed to this viral infection.

The unprecedented low profile of flu this past season is not credited, however, to a sudden enthusiasm for the annual flu shot. Instead, it is attributed, in the main, to other public health measures aimed at preventing COVID-19, such as mask wearing and social distancing. Nonetheless, in this week’s Germ Gems post, I make the case that the evidence for getting your annual flu shot is even stronger this year than last. And you might want to combine it with a COVID-19 vaccine “booster,” but that is a much more complicated decision.

Not the time for complacency. As already mentioned, the marked decrease in flu cases this past season is attributed largely to measures to prevent respiratory transmission of SARS-CoV-2—measures that also just happen to work for influenza virus. Other factors also likely played a role such as the record number of flu vaccinations (193.8 million doses) that were administered in the 2020-2021 flu season.

While we can certainly cheer the decline in flu cases this past year, many experts worry that we will experience a boomerang in cases this flu season. The article “The Flu Is Expected to Make a Comeback This Year, Threatening Hospitals Strained by Delta” in the September 9th Wall Street Journal, predicted that the coming flu season is on track to be much worse than the last cycle, thus straining hospitals already overwhelmed by the surge of the SARS-CoV-2 Delta variant. Therefore, it is essential that everyone who is eligible get a flu shot. We cannot be complacent.

Who should get the flu vaccine and when? The answer to the first part of this question is easy and hasn’t changed in recent years—everyone (with rare exceptions) over 6 months of age. Your primary care provider can fill you in on the details regarding the rare exceptions and other pertinent aspects of flu vaccines.

As in past years, the composition of this year’s flu vaccine has been updated based on the predicted influenza A and B strains most likely to cause this season’s flu epidemic. All flu vaccines this year, however, are quadrivalent meaning they contain four influenza A and B strains. For people 65 or older, a higher dose vaccine, such as Fluzone High-Dose Seasonal Influenza Vaccine, is recommended.

And you should get vaccinated now. Flu season in the U.S. lasts from October to May. But it takes about two weeks for the vaccine to fully kick in, so now is the time to get yourself and your kids jabbed.

Flu vaccine may protect against COVID-19. Interestingly, just as the COVID-19 pandemic appears to have lessened the impact of influenza, recent reports suggest there may be a reciprocal beneficial effect of getting a flu shot in protecting us against the serious events associated with SARS-CoV-2 infection. According to a study published on August 3rd in PLOS ONE, influenza vaccination had a protective effect against developing severe COVID-19 that lasted for up to 120 days after a COVID-19 diagnosis. The mechanism underlying such a potential benefit is not known, but it is postulated that the flu vaccine stimulates natural immunity that may carry over or cross protect against other unrelated viruses, such as, SARS-CoV-2.

Do not, however, rely on the flu shot to boost your immune response to COVID-19. The most convincing way to bolster your immunity against SARS-CoV-2 is to get yourself vaccinated against it. And if you haven’t done that yet, DO IT NOW!

A pandemic of the unvaccinated. In the U.S., COVID-19 has turned into a pandemic of the unvaccinated. According to the CDC, unvaccinated Americans are 11 times more likely to die of COVID-19. Thus, the extraordinary benefit of vaccination against COVID-19 cannot be exaggerated. It is a life versus death decision.

From the very beginning, it was recognized, however, that none of the COVID-19 vaccines is perfect. As with all vaccines, side effects can and do occur. Nonetheless, the benefits of getting a COVID-19 vaccination far outweigh the side effects.

Moreover, none of the vaccines is totally effective against all SARS-CoV-2 mutants, especially the Delta variant. On August 25, the CDC reported that due to Delta vaccination protection had fallen from over 90% to 66%. While this two-thirds protection is still very impressive, there is concern about the rising number of cases of “breakthrough” infections.

Do “breakthrough” infections warrant a booster? Stories about fully vaccinated people getting COVID-19—so-called breakthrough infections—surfaced throughout the summer suggesting that Delta virus might be changing everything. In response, several industrialized nations such as Israel, the Czech Republic, Germany, and France began offering booster shots for fully vaccinated people over 60. In addition, on August 18, 2021, President Biden called for a third shot or “booster” starting on September 20, 2021.

The necessity of third COVID-19 shots is dividing the scientific community. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said a third shot is “very likely” needed for a full regimen. Other experts, however, say there isn’t enough evidence yet to justify launching boosters.

In addition, the inequality of vaccine distribution to rich countries has left poorer countries behind and has made World Health Organization Director-General Tedros Adhanom Ghebreyesus a strong opponent of routine booster shots for protection against COVID-19. In response, President Biden recently called for a vaccine conference at the United Nations General Assembly to address this huge challenge.

While most studies of breakthrough infections show that they are uncommon and often mild, this is not always the case. Therefore, administration of a booster dose (a third dose of an mRNA vaccine or a second dose of the Johnson & Johnson [Janssen] vaccine) does make sense. On the other hand, a number of experts believe the fears of breakthrough infections are exaggerated and that President Biden jumped the gun (for example, see the August 20 article, ‘We Sent a Terrible Message’: “Scientists Say Biden Jumped the Gun With Vaccine Booster Plan” by Rachana Pradhan in Kaiser Health News). These experts make an equally compelling case against booster doses for everyone.

Personally, I believe that the U.S. administration lacks the data to justify a broad rollout of booster shots and should concentrate instead on vaccinating the over 25 percent of Americans who are eligible for shots but remain unprotected. That said, there is no argument against providing boosters for one group of people, namely, those who are moderately to severely immunocompromised identified by the CDC as people who have:

  • Been receiving active cancer treatment for tumors or cancers of the blood

  • Received an organ transplant and are taking medicine to suppress the immune system

  • Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system

  • Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)

  • Advanced or untreated HIV infection

  • Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response.

The twindemic of flu and COVID-19. We were fortunate that the flu season was virtually non-existent last year. It is speculated, however, that we will not be as lucky this year.

Many of the precautionary measure we took to help stop the spread of COVID-19 also helped stem the tide of flu in 2020-2021. Appropriately, most of these measures have been relaxed due to the availability of three highly effective and safe COVID-19 vaccines. Restaurants have reopened, kids have returned to in-person school, many organizations have resumed normal or near normal activities, and mask wearing and social distancing have become nonexistent in certain areas and among certain sectors of the population. In other words, society is returning to normal or, at least, a new normal.

The influenza virus did not, however, disappear; it remains a major killer. Each year a new strain of the influenza virus attacks our species. Some strains are more virulent than others. We need to keep in mind that waiting in wings are strains of virulent avian influenza, like H5N8, with a high risk of human-to human transmission that could blossom into the next pandemic. Thus, for the foreseeable future, all of us will need an annual flu shot tailored for the circulating flu strains.

Also, the urgency of getting all eligible people around the world vaccinated against COVID-19 cannot be overstated. In the U.S., the numbers of COVID-19 infections are ten times higher than they should be to end the pandemic. Therefore, getting vaccinated shouldn’t be a choice; it should be a must. Right now, it is too early to tell whether we will also need annual COVID-19 booster shots in the future. But if we do, they can be given safely together with a flu shot.

The influenza virus and SARS-CoV-2 are going to remain major coconspirators for the foreseeable future. The good news, however, is that many brilliant scientists, public health experts, and leaders in the pharmaceutical industry are focused on the development of universal vaccines against all strains of influenza and of SARS-CoV-2 variants. These vaccines will, in all likelihood, be developed. In the meantime, it is up to all of us to do what we can to protect ourselves against the flu and COVID-19. In both cases, the answer is simple: Get a flu shot and the COVID-19 vaccine!

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Sep 15, 2021





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Main Page images courtesy of Shuxian Hu, MD. Dr. Hu is a scientist in the Neuroimmunology Research Laboratory at the University of Minnesota.

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