On October 21 CDC director Rochelle Walensky issued a ruling that clears the way for booster shots of the Moderna and Johnson & Johnson vaccines to begin rolling out immediately. Anyone 18 and older will be able to get a second dose of the Johnson & Johnson vaccine at least two months after their first dose. Meanwhile, U.S. regulators’ recommendation for the Moderna vaccine is narrower: A third dose can be administered at least six months after the second one to people age 65 and older and to those ages 18 to 64 who are at high risk of severe COVID-19 due to underlying conditions. It also includes people ages 18 to 64 who are at high risk of exposure because of where they work or live, such as health-care workers or incarcerated people. These guidelines are the same as those approved for Pfizer’s booster doses.
The CDC also endorsed a “mix and match” approach to booster doses, which will, for example, allow people who received a Johnson & Johnson jab to seek a Pfizer or Moderna booster instead. Only people who are eligible for booster doses will be authorized to mix and match. U.S. regulators based the decision on evidence from a new National Institutes of Health study suggesting that booster doses of the Moderna or Pfizer vaccines are more effective for people who originally received the Johnson & Johnson shot.
The CDC’s recommendations align with the FDA emergency use authorization that had been issued the previous day.