Mix-and-match COVID-19 booster shots could be available by the weekend after a crucial federal committee unanimously voted to allow them Thursday.

Letting Americans choose among the Pfizer-BioNTech, Moderna and Johnson & Johnson vaccines as a COVID-19 booster shot would increase protection against the disease that is killing on average 1,093 Americans a day, the committee said.

It also voted to recommend a second shot for all 15 millions Americans who received the one-dose J&J vaccine, as well as a booster dose for certain groups of people who got the Moderna vaccine.

The vote by the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices is the second-to-last step in the booster authorization process.

Once CDC Director Dr. Rochelle Walensky signs off on the recommendation, which is expected to happen quickly, Moderna and J&J boosters can begin to be offered in the United States.

Do you need another shot? Can you mix and match vaccines? COVID booster questions, answered.

The committee made its decisions based on data presented by the vaccine makers and a National Institutes of Health study. It also considered the endorsement of similar recommendations Wednesday by the Food and Drug Administration.

A booster of the Moderna vaccine was recommended at least six months after people get their second shot, but only for those 65 and older or 18 and older if they’re at high risk for severe COVID-19, or their jobs or living conditions put them at high risk of exposure to the virus.

A second dose of the J&J vaccine was recommended for everyone who received their first dose at least two months ago.

A booster dose is not required for a person to be considered fully immunized. People who received two doses of either Pfizer-BioNTech or Moderna, or one dose of J&J, are fully immunized.

All booster doses will be free, just as all COVID-19 vaccines are, Reddy said.

FDA authorized Pfizer-BioNTech booster shots for people 65 and older or at high risk for COVID-19 because of health problems, jobs or living conditions on Sept. 22.

The CDC committee votes came after more than six hours of presentations and discussions.

Moderna presented information showing the efficacy of the vaccine after a two-dose series fell over time and most sharply after the rise of the delta coronavirus variant. This resulted in more breakthrough cases of COVID-19 in fully vaccinated people.

Testing of a booster dose of Modera at least six months after their second shot showed a 16- to 22-fold increase in neutralizing titers against the delta variant, Moderna told the committee.

The Moderna booster dose is 50 micrograms, one-half the initial 100 micrograms of the initial two doses. Moderna used the smaller dose because it restored the level of immunity as well as a larger dose.

“Our goal is to always use the dose that is most optimally effective for boosting,” said Dr. Jacqueline Miller, Moderna’s senior vice president for infectious diseases.

Johnson & Johnson presented data showing that a single dose of its vaccine provided 74% protection against severe disease globally and 70% protection against all symptomatic disease. Trends over time showed a decline in effectiveness against symptomatic COVID-19, most likely linked to coronavirus variants, said Dr. Peggy Heaton, the company’s global therapeutic area head for vaccines.

But the CDC has reported the J&J vaccine was only 68% effective against hospitalization in most adults and was not equivalent to the protection provided by either the Moderna or Pfizer-BioNTech vaccines.

Johnson & Johnson presented studies showing that in the United States, protection against all systemic disease rose to 94% after a booster dose of its vaccine at two months. There were no severe cases of COVID-19 among those who received the booster, making the vaccine 100% effective, the company said

A smaller pool of data showed the booster dose of the J&J vaccine at six months was even more potent that at two months. It resulted in a 12-fold increase in antibodies, the company said.

Side effects among those who received the boosters were very rare and lower than among those who received the first dose.

More than 189 million people in the United States have been fully vaccinated against COVID-19, about 57% of the total population. Hospitalization rates among unvaccinated Americans are between nine and 15 times higher than among vaccinated people, according to the CDC.

Almost 6% of fully vaccinated Americans have already received a COVID-19 booster shot, according to CDC data.

This article originally appeared on USA TODAY: CDC advisory panel OKs J&J, Moderna and mix-and-match COVID boosters