COVID-19 Booster Shots: What You Need to Know

booster shot grand journey - three vials of vaccine with people climbing on them

COVID-19 booster shots are ready when and if we need them. 

In the United States, PfizerModerna, and Johnson & Johnson have each developed their own booster shots. So far, the Food and Drug Administration (FDA) has authorized third doses of both of the mRNA vaccines; Pfizer is authorized for use in immunocompromised people, adults 65 and older, and adults at high risk for severe COVID-19, while Moderna only is authorized for use in immunocompromised people.

But will the general public need booster shots? Scientists and health officials are still debating whether the existing vaccine regimen is effective enough to forgo boosters—at least for now—allowing for a focus on getting first doses to more of the world.

Because manufacturers have eagerly presented the FDA with clinical trial data for COVID-19 booster doses, there's a lot we already know about them. Moderna plans to administer half-size doses for its third shot, for example, and Johnson & Johnson's booster dose increases immunity nine-fold. 

Here, we asked experts what else we should know about boosters, from potential side effects to the intended rollout plan and timeframe. There's good news: After the bumpy road to COVID-19 vaccine distribution the first time around, the U.S. is more prepared than ever. 

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2 Sources
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  1. Moderna. Moderna announces positive initial booster data against SARS-CoV-2 variants of concern. May 5, 2021.

  2. Johnson & Johnson. Johnson & Johnson announces data to support boosting its single-shot COVID-19 vaccine. August 25, 2021.