An advisory committee to the Food and Drug Administration (FDA) voted unanimously last Friday to recommend a Johnson & Johnson booster shot for the roughly 15 million Americans who received the one-dose Covid-19 vaccine. The company told the FDA that an extra dose of the vaccine boosts protection as early as two months after the initial shot, and might be more effective when given after six months. Experts say the recommendation, which applies to those 18 and older, could be accepted by the FDA and Centers for Disease Control and Prevention (CDC) as early as the end of the week.
The announcement comes a day after the panel recommended booster shots of the Moderna vaccine for certain groups, and a month after the group recommended Pfizer-BioNTech boosters. During the meeting, Johnson & Johnson presented data from early studies showing their vaccine's protection remained largely stable over time, but that a second dose offers a much-needed bump in protection, according to NPR’s Scott Hensley. A CDC study released last month found that the J&J vaccine was around 68 percent effective against Covid-19 hospitalization, compared to 93 percent for Moderna and 88 percent for the Pfizer-BioNTech vaccine. The single-dose vaccine's protection was substantially lower than Moderna and Pfizer’s mRNA vaccines, leading experts to recommend a second dose.
“I think this frankly was always a two-dose vaccine,” says FDA adviser Paul Offit of Children’s Hospital of Philadelphia to the Matthew Perrone and Lauran Neergaard for the Associated Press. “It would be hard to recommend this as a single-dose vaccine at this point.”
The decision is the latest in a number of recommendations over the past few months to authorize boosters for all three vaccines available within the United States. In combination with the already-authorized Pfizer and Moderna boosters, over 100 million fully-vaccinated people will be eligible for boosters if the FDA and CDC endorse the panel’s recommendation.
The committee also pointed to evidence that some Johnson & Johnson recipients might have a stronger immune response by “mixing and matching” different shots. Early studies show that Johnson & Johnson recipients who got a Moderna and Pfizer booster saw their antibody levels rise 76-fold and 35-fold respectively within 15 days. By comparison, those who got a second dose of the J&J booster had just a four-fold rise in antibody count. Panelists noted that studies on mixing vaccine types are limited, and antibody levels may not be a perfect indicator of protection against Covid-19, reports Popular Science’s Claire Maldarelli. Because the J&J shot offers the lowest level of protection of the three shots, panel members thought it would be unfair to deny Johnson & Johnson recipients a booster after green-lighting the mRNA-based shots.
“There is a public health imperative here, because what we’re seeing is that this is a group with overall lower efficacy than we have seen with the mRNA vaccines,” says Arnold Monto, the committee’s acting chairman and a professor of epidemiology at the University of Michigan School of Public Health to the New York Times. “So there is some urgency there to do something.”
Some experts are still skeptical about whether booster shots are needed for most people yet, despite the ambitious goals of the Biden Administration to offer additional doses to Americans. Fully vaccinated people are still well-protected from infection, hospitalization, and death, and some say resources should to be put toward reaching more than 60 million unvaccinated Americans. Since the Delta variant has taken hold of the United States, those who have failed to get vaccinated are ten times more likely to be hospitalized and die from Covid-19.
"If the mRNA vaccines from Pfizer and Moderna had not been so utterly, amazingly effective—95 percent—then Johnson & Johnson would look like a hero with their one dose, but I guess our standards are being set awfully high here by the other vaccines," says Francis Collins, director of the National Institutes of Health, to Aya Elamroussi for CNN.
As of last week, more than 95 percent of people ages 65 years or older have received at least one dose of a Covid-19 vaccine, and around 84 percent are fully vaccinated. More than three-quarters of people ages 18 years or older have received at least one dose of a vaccine, and around 68 percent are fully vaccinated. Since the FDA authorized booster shots of Pfizer and Moderna’s vaccines to older Americans and other high-risk groups, more than nine million American’s have opted to get the third jab. The FDA will meet later this month to discuss authorizing a Moderna booster for teens, and a lower dose of the Pfizer booster for kids 5 to 11.