Some people who get the Pfizer-BioNTech and Moderna coronavirus vaccines should consider waiting longer for a second dose, according to the Centers for Disease Control and Prevention guidelines updated on Tuesday. The agency currently recommends an 8-week interval between the first and second shots for some people over 12, especially boys and men 12 to 39 years old.
The new change, which does not affect people who have been vaccinated, applies to about 33 million people who have not been immunized. And the CDC still recommends initial periods — three weeks for Pfizer-BioNTech and four weeks for Moderna — for certain people, including those with weakened immune systems from moderate to severe, 65 years of age or older, or at risk of severe Covid-19 disease.
The change comes from search shows that longer dosing intervals can increase the effectiveness of a vaccine and reduce the risk of a serious but uncommon side effect called Myocarditis, or inflammation of the heart. The overall incidence of myocarditis following vaccination is low. ONE study conducted in Israel estimated that nearly 11 out of every 100,000 men aged 16 to 29 had myocarditis.
Earlier this month, an independent scientific advisory panel to the CDC The study looked at myocarditis that support an extended period between doses. Research has shown that adolescent boys and young men have a higher risk of developing these heart problems after a second dose of Pfizer-BioNTech or Moderna vaccines.
However, the absolute risk of myocarditis is very small, most cases are mild and short-livedand research shows that coronavirus infection is more likely to cause heart problems than the Covid-19 vaccine. Patients of all ages infected with the virus are nearly 16 times more likely to develop myocarditis than uninfected patients, according to one study. CDC Report.
People who waited six to 14 weeks between the first two doses of the Pfizer-BioNTech or Moderna vaccine had higher antibody responses than those who waited the standard three or four weeks, according to the study. present CDC report from meeting. And the vaccine’s effectiveness against infection and hospitalization is also higher with a six to eight week interval between doses.
When the vaccine was first rolled out, the priority was to fully immunize everyone as quickly as possible, according to the presentation. Now, more than a year since the US vaccination campaign, more data is available to guide vaccination schedules, the presentation noted.
Public health experts say longer dosing intervals mean there is a risk of people becoming infected after just one shot. But they say the change could affect some unvaccinated people and parents concerned about the potential risk of myocarditis.
At the panel meeting, Dr. Matthew Daley, senior investigator at Kaiser Permanente in Colorado and member of the advisory committee, said, “If the message is, ‘We’ve got a vaccine or vaccines are highly effective and safe, and this is an approach to making them safer,’ that might convince some people. “
Benjamin Mueller contribution report.
https://www.nytimes.com/2022/02/23/health/pfizer-moderna-vaccine-dose-men.html The CDC advises some people to wait longer between the first and second dose of Pfizer or Moderna vaccine.