Key TakeawaysNew guidelines from the CDC recommend people over the age of 12 and young men wait as long as eight weeks before receiving the second dose of the Pfizer or Moderna COVID-19 vaccine.Extending intervals between COVID-19 vaccines can reduce the risk of myocarditis.If the second shot is delayed for more than eight weeks, health experts suggest getting it as soon as possible to receive full protection against COVID-19 infection.

Key Takeaways

New guidelines from the CDC recommend people over the age of 12 and young men wait as long as eight weeks before receiving the second dose of the Pfizer or Moderna COVID-19 vaccine.Extending intervals between COVID-19 vaccines can reduce the risk of myocarditis.If the second shot is delayed for more than eight weeks, health experts suggest getting it as soon as possible to receive full protection against COVID-19 infection.

Some people can space out the first and second doses of the Pfizer and Moderna COVID-19 mRNA vaccines for as long as eight weeks, according tonew guidancereleased Tuesday, February 22, from the Centers for Disease Control and Prevention (CDC).

The guidance is especially aimed at people over the age of 12 and males between the ages of 12 to 39.

Original guidance from the CDC recommended that the second dose be administered three weeks after the first shot of the Pfizer vaccine and four weeks after the first shot of the Moderna vaccine.

The CDC said vaccines remain safe and effective even if people follow the originally recommended time interval, but extending the interval may reduce the rare risk ofmyocarditis, a type of heart muscle inflammation, particularly among certain groups.

How Is the New Guidance Different?

According to the CDC, people older than 12 and young men who wait as long as eight weeks before getting their second COVID-19 vaccine dose can reduce the small risk of developing myocarditis.

Intervals longer than four weeks can also increase antibody response and vaccine effectiveness.

Lee Wetzler, MD, professor of medicine at Boston University School of Medicine, told Verywell while the new guidance does not apply to or change anything for people who are fully vaccinated, there is evidence that spreading out vaccine doses for longer can enhance immunity—a consideration for those who are not vaccinated yet or are waiting to get their second dose.

Can You Get a Flu Shot and a COVID Vaccine at the Same Time?

“Waiting six or eight weeks is not as big of a deal as it used to be when we were seeing so many people infected and getting sick,” he said. “In the midst of the pandemic, we were trying to raise immunity as quickly as possible. Even though there’s still disease around now, it appears we have a little more leeway and if we increase the interval, overall immunity seems to be enhanced.”

The CDC still recommends the three or four-week interval for people who are moderately or severely immunocompromised, adults 65 and older, and others who need rapid protection due to increased concern about community transmission or risk of severe disease. Officials added since there is no data available for children younger than 11, this group is still recommended to get the second Pfizer vaccine three weeks after the first dose.

Why Now?

“It’s like trying to fly an airplane while you’re building it,” Wetzler said. “We’re going to learn a lot more and we should never stop looking at this because this is not the last time we’re going to see something like this. We can apply it to the next time we have a pandemic.”

What Happens If I Get COVID-19 Between Vaccine Doses?

He added new recommendations including longer vaccine schedules will be beneficial for people who have yet to be vaccinated, including new generations, and it can bring guidance to existing communities if shots will be needed in the foreseeable future.

“New recommendations are not pointless in any respect,” he said. “Depending on what happens with epidemiology and immunity, I think the pandemic will be around for the rest of our lives. But whether we’re going to have to take the shot for the rest of our lives is unclear because we really don’t know the level of immunologic memory yet.”

Paul Auwaerter, MD, a professor of medicine at Johns Hopkins University, told Verywell in an email he believes additional vaccines may be needed for certain groups, such as those who are 65, to maintain sufficient protection.

“For others, it remains to be seen if a fourth booster dose is required over time as it does not appear to be necessary from what we know with the Omicron surge,” Auwaerter said. “If a new variant subsequently emerges, that evades vaccine protection or is more virulent if acquired, we may see reformulation of the vaccine to suit.

What This Means For YouVaccines remain safe and effective at original intervals but extending the interval time for the second dose to eight weeks may reduce the risk of heart inflammation and can promote antibody protection. The benefits of both mRNA vaccines far outweigh the risk of myocarditis compared to not getting vaccinated.

What This Means For You

Vaccines remain safe and effective at original intervals but extending the interval time for the second dose to eight weeks may reduce the risk of heart inflammation and can promote antibody protection. The benefits of both mRNA vaccines far outweigh the risk of myocarditis compared to not getting vaccinated.

Can Waiting Too Long Be Risky?

According to Wetzler and the CDC, getting the first vaccine shot gives you some protection against COVID-19, but immunity can wane over time. The second shot of the two-dose vaccines is essential for reaching immunity against COVID-19.

Wetzler said if people wait beyond the recommended guidelines to get their second dose, it can impact the body’s ability to develop a good, protective, and full-immune response.

Can a Second COVID-19 Vaccine Dose Be Delayed?

“Now if you get the second shot too soon there really is no risk, but you might need to get another shot a couple of weeks after that,” he said. “If you get it a week later after your first shot, you might not induce a good immune response if you were to wait three or four weeks later.”

He adds evenif your second shot is delayedfor weeks or even months, you should still get it as soon as possible as the second dose provides added protection.

In the updated guidance, the CDC has not changed the interval of at least five months between completing the initial two-dose vaccine series and receiving a booster shot.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit ourcoronavirus news page.

4 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States.Centers for Disease Control and Prevention.COVID-19 vaccines that require 2 shots.Centers for Disease Control and Prevention.Antibodies and COVID-19.Thompson MG, Burgess JL, Naleway AL, et al.Interim estimates of vaccine effectiveness of BNT162b2 and mRNA-1273 COVID-19 vaccines in preventing SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers — eight U.S. locations, December 2020–March 2021.MMWR Morb Mortal Wkly Rep.70(13);495–500. doi:10.15585/mmwr.mm7013e3

4 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States.Centers for Disease Control and Prevention.COVID-19 vaccines that require 2 shots.Centers for Disease Control and Prevention.Antibodies and COVID-19.Thompson MG, Burgess JL, Naleway AL, et al.Interim estimates of vaccine effectiveness of BNT162b2 and mRNA-1273 COVID-19 vaccines in preventing SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers — eight U.S. locations, December 2020–March 2021.MMWR Morb Mortal Wkly Rep.70(13);495–500. doi:10.15585/mmwr.mm7013e3

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Centers for Disease Control and Prevention.Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States.Centers for Disease Control and Prevention.COVID-19 vaccines that require 2 shots.Centers for Disease Control and Prevention.Antibodies and COVID-19.Thompson MG, Burgess JL, Naleway AL, et al.Interim estimates of vaccine effectiveness of BNT162b2 and mRNA-1273 COVID-19 vaccines in preventing SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers — eight U.S. locations, December 2020–March 2021.MMWR Morb Mortal Wkly Rep.70(13);495–500. doi:10.15585/mmwr.mm7013e3

Centers for Disease Control and Prevention.Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States.

Centers for Disease Control and Prevention.COVID-19 vaccines that require 2 shots.

Centers for Disease Control and Prevention.Antibodies and COVID-19.

Thompson MG, Burgess JL, Naleway AL, et al.Interim estimates of vaccine effectiveness of BNT162b2 and mRNA-1273 COVID-19 vaccines in preventing SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers — eight U.S. locations, December 2020–March 2021.MMWR Morb Mortal Wkly Rep.70(13);495–500. doi:10.15585/mmwr.mm7013e3

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