Israel, COVID-19, booster shot
A man receives a third dose of a COVID-19 vaccine in the central Israeli city of Modi’in, August 17, 2021. Photo credit: © Gil Cohen Magen/Xinhua via ZUMA Press

Wait, do I have to get poked again?

With the first round of COVID-19 vaccine rollouts still ongoing, and approximately 40 percent of Americans yet to receive the first dose of any vaccine, a new question has gained traction: Will everyone need booster shots of the COVID-19 vaccine? 

Last week, booster shots were officially authorized by the FDA and recommended by the CDC for moderately to severely immunocompromised people. If booster shots are soon to be required for everyone, we need to know: What are they? Will a COVID-19 booster be safe? Effective? What will the timeline for getting your booster look like? And, in whose best interest, exactly, is it to produce and mandate booster shots? 

Let’s look at the arguments for and against supplying COVID-19 booster shots to the general public, and the history and science of booster shots in general.

Cellular Lifeguards

To get a booster shot means to receive an extra dose of a vaccine in addition to a previous first full cycle of immunization. A booster dose is like the lifeguard certification renewal test. Lifeguards have to get certified to save you from drowning. Similarly, vaccines are like that initial training for immune system cells to fight a virus. And, just as a lifeguard could gradually forget first aid protocols, so too can immune cells’ abilities to respond to pathogens decrease over time, especially if they do not encounter illness. That’s called “waning immunity.” 

Thus, lifeguards must recertify their abilities to practice first aid, and our immune cells must recertify their ability to respond to pathogens. While waning immunity does not occur for every disease, there has been mounting concern that the COVID-19 vaccine will need a booster after approximately 6 to 12 months.

Booster doses for vaccines are not new. Booster shots are given to the general population to prevent a number of different diseases: doctors recommend tetanus boosters every 10 years; polio boosters are given to 4- to 6-year-olds who were vaccinated shortly after birth; and whooping cough boosters, called Tdap, are given every 10 years to supplement the vaccine used for initial immunization. Other vaccinations that require boosting? Shingles, pneumonia, hepatitis A and B, and measles, mumps, and rubella.

COVID-19, vaccine, Brazil

Olga Maria Freire, 73, reacts to being vaccinated during the first day of vaccination against COVID-19 for people over 70, in Brazil on February 8, 2021. Photo credit: International Monetary Fund / Flickr (CC BY-NC-ND 2.0)

Mixed Messages

There are a few conversations about whether (and when) the general public might require booster shots for their COVID-19 vaccines. Among them, the most prominent concerns include questions of pharmaceutical company motivations, vaccine supply, and vaccine efficacy. Altogether, they paint a muddy picture of just how crucial, or useful, a COVID-19 booster dose may prove to be.

Shots for Whom?

As of August 12, the FDA authorized a booster shot of the COVID-19 vaccine for select groups of immunocompromised people who are at higher risk for getting severely sick. The following day, the CDC and Dr. Anthony Fauci recommended booster shots for immunocompromised groups, citing their additional risk for “breakthrough cases” and potentially continuing to spread the virus due to incomplete immunity after first vaccination. 

In contrast, the FDA has not approved a booster dose of any COVID-19 vaccine for the general population. The Biden administration and pharmaceutical companies called for booster shots to be made available as early as September 20. Pfizer and Moderna have both begun conducting trials to determine the efficacy of a booster. Both companies stand to gain billions of dollars in sales with the distribution of booster shots. This monetary motivation begs the question of whether booster shots will actually offer substantial additional protection against infection, or whether it’s a cash grab.

What’s the Rush?

Among the voices against mandating a COVID-19 booster dose are infectious disease specialists who examined data regarding breakthrough cases and the Delta variant and believe that a booster will only be necessary if vaccinated people begin to require hospitalization. 

Furthermore, the WHO decried the rush to distribute booster shots (or first-dose COVID-19 vaccines to children) in highly developed countries before the populations of more vulnerable countries have been supplied with their first doses. 

What About Efficacy?

A third substantial concern circles the question of the continued efficacy of the existing COVID-19 vaccines. A concerning study from Israel reported that the Pfizer vaccine’s effectiveness in preventing infection dropped from over 90 percent to 39 percent, and to 41 percent for symptomatic illness. Similarly, a Mayo Clinic study found the Pfizer vaccine dropped from 76 percent to 42 percent in effectiveness when the Delta variant rose in prominence in the US. 

The US government also found that COVID-19 vaccination effectiveness in nursing homes dropped from 74.7 percent to 53.1 percent following the rise of the Delta variant. 

There are doubts over whether the decline of vaccine efficacy is as severe a picture as the Israeli study paints: A conflicting UK report found that the Pfizer vaccine was still 88 percent effective in preventing symptomatic illness. Still, more recently, an observational study conducted by Israeli health care group Maccabi Health Services supports the increased efficacy of a booster shot, finding that the risk of infection was reduced by 86 percent in a group of participants aged over 60. 

As older populations are more at risk for serious illness due to COVID-19, booster shots will be distributed in the same order as the initial vaccines: to health care workers, nursing home residents, and so on.

A Boost of Confidence

A few promising conclusions can be drawn:

    1. Booster shots have been around for a long time, and have proven effective in providing continued immunity against a long list of infectious diseases. 
    2. The scientific and political consensus supports the benefit booster shots provide to protecting immunocompromised groups and other higher risk groups, such as the elderly. 
    3. Multiple studies support that vaccination, whether in the first dose or in booster form, helps to prevent a large percentage of cases of serious illness due to COVID-19. 

Certainly, there are serious ethical concerns regarding whether the vaccine supplies should go toward more vulnerable nations before they’re offered to the already-vaccinated populations of richer countries. There is little data concerning the risks of receiving a booster dose of the vaccine, but for immunocompromised people who have received third doses, the reported side-effects have most commonly been mild to moderate fatigue and pain at the injection site. 


  • Audrey Ruan

    Audrey Ruan is a junior reporter covering health and medicine for WhoWhatWhy. She is a pre-med student at Emory University on track to double major in English and Neuroscience and Behavioral Biology.

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