Want CNET to notify you of price drops and the latest stories?

CDC Suggests Some Can Wait Longer to Get Second Pfizer, Moderna Shot

A two-month interval between the first and second doses of a COVID vaccine "may be optimal" for some people, the CDC says.

Jessica Rendall Wellness Writer
Jessica is a writer on the Wellness team with a focus on health news. Before CNET, she worked in local journalism covering public health issues, business and music.
Expertise Medical news, pregnancy topics and health hacks that don't cost money Credentials
  • Added coconut oil to cheap coffee before keto made it cool.
Jessica Rendall
3 min read
Nora Carol Photography/Getty Images
For the most up-to-date news and information about the coronavirus pandemic, visit the WHO and CDC websites.

The US Centers for Disease Control and Prevention late last month adjusted the number of weeks that some people can wait to receive their second dose of Pfizer's or Moderna's mRNA vaccine.

In clinical guidance updated Feb. 22, the CDC recommends that people age 12 and up can receive the second dose of Moderna's COVID vaccine four to eight weeks after the first dose, and the second dose of Pfizer's three to eight weeks after the first dose. 

Previously, the guidance was to get a second dose three or four weeks after the first shot, respectively. 

In its updated COVID-19 schedule, the CDC notes that the two-month interval "may be optimal" for some people, including males 12 to 39 because they have a higher risk of myocarditis, a rare side effect. The already small risk may be reduced by waiting a little longer. 

But the new schedule also gives extra breathing room for a potentially more potent antibody response if people wait slightly longer, and can reduce the stress of needing to schedule an appointment exactly on time. 

Older adults, people who are immunocompromised, and those who need fast protection because of their risk for severe disease or a high level of COVID-19 in their community should still get their second dose three or four weeks after their first. The new guidance also only applies to people 12 and up, who receive a full-dose mRNA vaccine. (Pfizer's vaccine for kids 5 to 11 is a smaller dose.)

Here's how the new vaccine schedule might affect you.

Watch this: COVID didn't cause a total urban exodus, but it did shift America's landscape

What does this mean if I'm already vaccinated?

Nothing. The small tweak to the COVID-19 schedule only applies to people who haven't been vaccinated yet. It may also influence future guidance, should there be a seasonal COVID-19 vaccine or something similar. 

The recommended time frame for when you should get your COVID-19 booster or third shot has not changed: Get a booster five months after your second dose of Pfizer or Moderna, or two months after Johnson & Johnson's vaccine. For people who are moderately or severely immunocompromised, they should receive a third dose of a vaccine at least four weeks after the second, and a fourth shot or booster three months after their third dose.

Most people should opt for a booster or primary vaccine series of Moderna's or Pfizer's vaccine, rather than J&J, the CDC says, unless you can't take either mRNA vaccine or prefer the one-dose vaccine.


Boosters are available for everyone 12 and up in the US. The World Health Organization recommends boosters for optimal protection against the omicron variant, a change to its previous policy that prioritized vaccine equity.

skaman306/Getty Images

Why did the CDC change the guidance? 

Some studies in adolescents suggest that the small risk of myocarditis might be reduced if there's more space between the first and second dose, the CDC reports. Myocarditis is a rare vaccine side effect that typically resolves quickly, but the risk, though small, is higher for males 12 to 39 years old.

The agency also said there might be a higher antibody response, and vaccine effectiveness may actually increase if someone waits slightly longer before getting the second dose.

But because one dose doesn't provide as much protection as two doses, the CDC recommends that people most at risk for severe COVID-19 stick to the three-week waiting period for Pfizer's vaccine, and four-week period for Moderna's vaccine to get protection as fast as possible.

Receiving either vaccine at three or four weeks continues to be safe. For everyone 5 and up, COVID-19 vaccination is recommended as the benefits of protection against severe disease "far outweigh" the potential risks of an adverse reaction.

What about kids?

The schedule for kids 5 to 11 is still the same: Get a second shot of Pfizer's small-dose COVID-19 vaccine three weeks after the first dose. Doctors and health officials continue to emphasize the safety of the vaccine for kids as young as 5, and it's one-third the adult dose given to people age 12 and up.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.