Third dose?

Covid-19 booster shots: 8 questions and science-backed answers

Your questions about the third dose, answered.

Originally Published: 
The Simpsons via Giphy


September 20, 2021, was technically the first day that some people who received their second shot of the Pfizer Covid-19 vaccine were eligible for a booster in the U.S.


That being said, you probably have questions about boosters — especially because not every expert is advocating for widespread availability.


Here are 8 Covid-19 booster shots questions and answers:

8. Who should get a booster right now?

The CDC recommends that people who are at higher risk of illness and who were vaccinated early get a booster. Also, people 65 and older.


It’s still unclear if people with few health risks need boosters to stay protected — but a third shot should reinforce the body’s defenses.

7. Who can obtain a booster in the U.S.?

Only those aged 65 and older and people who are at high risk for severe Covid-19 can get a third shot of the Pfizer vaccine.

Pokemon via Giphy


On September 17, 2021, an FDA advisory panel announced there was insufficient evidence to recommend Pfizer boosters to everyone aged 16 and older.

A decision has not yet been made on Moderna boosters.

6. Is this booster shot the same formula I got 8 months ago?

Yes, it’s the same formula and the same dosage.

Carlos Sanchez Pereyra/Photodisc/Getty Images


The current boosters haven’t changed.

5. Are there boosters for all the vaccines?

Only Pfizer. Both Moderna and a J&J booster are on the way.

NurPhoto/NurPhoto/Getty Images


Johnson & Johnson announced on September 21, 2021, that trial data from its booster shot showed a strong immune response in people of all ages.

4. Can I mix and match vaccine shots?

Right now, the World Health Organization does not recommend it, but the CDC says it’s fine as long as you’re mixing two mRNA vaccines.


On the other hand, some studies are starting to show that some combinations might actually elicit higher immune responses than taking two doses of the same shot. This suggests switching it up may be better.

3. Are there side effects to booster shots?

For some. It’s similar to the first dose(s) of the vaccines.


Side-effects include soreness or swelling at the injection site, headaches, or a mild fever. It’s normal to not feel any side effects, too.

2. Will I be okay if I don’t get a booster right now?

It depends on your risk factors. But recent studies do show that initial vaccination is still effective against Delta and other variants.


Breakthrough cases do happen. But being vaccinated will most likely keep you out of the hospital.

Fede Cook via Giphy
1. Do we even need boosters?

That’s been a subject of debate among the CDC, FDA, and WHO. Recent data shows they work — but equity is another question.



The richest countries, including the U.S., have plentiful access to vaccines. Much of the world doesn’t.

Scientists agree that it’s more important to get first and second doses to those waiting for vaccines — rather than prioritize third doses for others.

Thanks for reading,
head home for more!