The panel voted 12 in favor of the vaccine and none against, with one recusal.
The committee acted with little debate following presentations showing the vaccine was 85 percent protective against severe Covid-19 disease across all clinical trial sites and provided complete protection against hospitalizations and deaths.
Late Sunday, Rochelle P. Walensky, the C.D.C. director, signed the committee’s recommendation, calling the new vaccine “another milestone toward an end to the pandemic.”
Experts pointed out that the Johnson & Johnson vaccine will be simpler to distribute than the other two vaccines, which are made by Moderna and Pfizer with its German partner BioNTech. It requires just one shot instead of two and can be stored in standard refrigerators instead of freezers. Health professionals have noted that it could be particularly well suited to remote areas and clinics as well as drive-through mass vaccination sites.
The committee weighed those advantages against the shot’s somewhat lower efficacy rate in clinical trials. Pfizer and Moderna’s shots each were shown to be about 95 percent protective against symptomatic Covid disease, whereas Johnson & Johnson’s was 72 percent efficacious against moderate to severe disease in U.S. trial sites.
Direct comparisons between the vaccines are problematic, however, because the trials were conducted in different locations at different times. For instance, Pfizer’s and Moderna’s vaccines were tested before troubling new variants of the virus emerged in Britain, South Africa and elsewhere.
The panel, the Advisory Committee on Immunization Practices, reviewed one recent survey showing that, given a choice between a two-dose vaccine as effective as Pfizer’s or Moderna’s or a single dose vaccine as effective as Johnson & Johnson’s, only 7 percent of respondents picked Johnson & Johnson’s. Twenty-one percent said they would take either.
Importantly, though, of the 58 percent of respondents who said they preferred a vaccine like Pfizer’s or Moderna’s, nearly half said they would take a vaccine like Johnson & Johnson’s rather than wait a month for one of the other two.
The committee met almost exactly one year after the first death associated with Covid-19 in the United States. The committee is expected to meet again on Monday and discuss all three vaccines, including how they might be best deployed among different population groups.
