Johnson & Johnson requested Tuesday that the Food and Drug Administration allow additional shots of the COVID-19 vaccine, as the U.S. government expands its booster campaign to millions of more Americans.

J&J claimed that it requested the FDA to approve boosters for people who had received its one-shot vaccine. Although J&J stated that it had data on booster intervals ranging from 2 to 6 months, it didn’t recommend any to regulators.

The FDA approved booster shots of Pfizer’s vaccine for older Americans, and other groups that are more vulnerable to COVID-19. This is part of a broad effort by the Biden Administration to protect against the potential waning vaccine immunity and the delta variant.

The extra Pfizer shots were supported by government advisers, but they also worried that confusion could be caused for the tens of million Americans who have received Moderna or J&J shots. Officials in the United States don’t recommend mixing different vaccine brands.

Next week, the FDA will convene an outside panel to review booster data from J&J as well as Moderna. This is the first step of a process that includes approval from both the FDA and Centers for Disease Control and Prevention. Americans could be receiving Moderna and J&J boosters if both agencies approve.

J&J released data indicating that its vaccine is still highly effective against COVID-19 at minimum five months after vaccination. This included 81% against hospitalizations in the U.S.

Research by company shows that a booster dose of either 2 or 6 months boosts immunity. The FDA advisers will examine the data and vote next Friday on whether boosters should be recommended.

Given that the FDA already had a meeting scheduled on the company’s data, the timing of the J&J file was not normal. Companies usually submit their requests far in advance of announcements about meeting dates. J&J executives stated that the company is working closely with FDA to review the request.

“Both J&J, FDA feel the urgency of COVID and we want to see good data and convert it into action as soon possible,” stated Dr. Mathai Mammen of J&J’s Janssen unit.

Because it only requires one shot, the vaccine developed by the New Brunswick, New Jersey company was seen as an important tool in the fight against the pandemic. Its rollout was hampered by a number of problems, including manufacturing issues at a Baltimore plant that caused J&J to import millions upon millions of doses.

Regulators have also added warnings about rare side effects, such as a blood disorder or neurological reaction called Guillain Barre syndrome. Both cases were ruled out by regulators because they did not consider the risks.

Moderna and Pfizer, rival drugmakers, have supplied the vast majority U.S. COVID-19 vaccinations. The two-dose shots from the companies have vaccinated more than 170 million Americans, while only 15 million Americans received the J&J shot.