(Reuters) – A panel of expert advisers to the U.S. health regulator is meeting on Friday to vote on the authorization of a booster shot of Johnson & Johnson (NYSE:)’s vaccine for people aged 18 and older, and the appropriate interval between the two doses.

The Food and Drug Administration’s advisers will decide if the booster shot should not be administered more than two months following the initial shot, or after at most six months.

Although the FDA may not be bound by their recommendations, they often do.

Independent expert advisors unanimously voted Thursday for booster shots Moderna COVID-19 is a vaccine that Inc offers to Americans 65 years and over, as well as those who are at risk for severe illness and occupational exposure.

The use of boosters for Moderna and J&J moves next week to a panel of advisers to the U.S. Centers for Disease Control and Prevention for its consideration, and then the CDC director.

U.S. agencies of health approved a boost dose Pfizer Inc (NYSE:), and BioNTechSE (NASDAQ:) last month’s vaccine.

A panel discussion will take place on Friday about the benefits of mixing and matching vaccines. This refers to giving booster shots with different doses than the initial dose. They will consider data from a National Institutes of Health study of 458 participants that received some combination of Pfizer/BioNTech, Moderna and J&J shots.

Data from the study was reported on Wednesday, showing that people who got J&J’s COVID-19 vaccine as a first shot had a stronger immune response when boosted with vaccines from Pfizer or Moderna.