In two unanimous decisions, a 15-member expert panel convened by the Centers for Disease Control and Prevention (CDC) today recommended booster doses for people who have been vaccinated with either the Moderna or Johnson&Johnson-Janssen COVID-19 vaccines. CDC director Dr. Rochelle Walensky will take this advice into consideration before making a final recommendation.
The CDC’s Advisory Committee on Immunization Practices (ACIP) recommends that anyone who was initially vaccinated with the Moderna shot get a booster at least six months later, while the committee recommends that J&J-Janssen recipients receive a booster at least two months after their initial vaccination. The endorsement follows a similar decision from an expert Food and Drug Administration (FDA) panel that allows people to receive any of the three authorized or approved COVID-19 vaccines, from Pfizer-BioNTech, Moderna and J&J-Janssen, as the booster dose. The Moderna booster will be half the dose of the original dose.
For now, the decision only applies to certain groups of people who have been vaccinated against COVID-19. Those include people over age 65, as well as people aged 18 to 64 who are at increased risk of severe COVID-19 due to underlying health conditions or who live or work in a higher risk setting. For example: health care workers, grocery store workers, teachers and those living in long-term care facilities or homeless shelters.
The CDC and FDA previously authorized a booster dose of vaccine made by Pfizer-BioNTech, and this decision supersedes and includes that authorization. As with the previous discussion about boosters, the 15-member committee were relatively agreed on two things: that due to the lower efficacy of J&J-Janssen’s vaccine, people who got that shot should receive a booster; and that for people vaccinated with the two mRNA vaccines from Pfizer-BioNTech and Moderna, those over age 65 and anyone with underlying health conditions, regardless of their age, should get a booster dose. The panel continued to debate the need for a booster dose among younger people whose jobs or living conditions present a higher risk.
Dr. Sarah Long, professor of pediatrics at Drexel University College of Medicine, asked “what available evidence is there that people under age 50 should receive a booster at this point?” When the committee discussed this population at the meeting when they decided on the Pfizer-BioNTech booster, they voted against recommending boosters for those under 50. But Walensky decided to allow people aged 18 to 64 years who are at high risk of occupational or institutional exposure to have the option of getting a booster. That final decision says that these groups can, rather than should, get a booster if they so choose.
“The last decision made in this regard is not the correct decision,” Long said, referring to today’s final recommendation. “And we are somewhat stuck with it. I can’t say that I am comfortable that anybody under age 50—otherwise healthy individuals—needs a booster at this time, either with Moderna or Pfizer-BioNTech.” Long noted that the data for this age group aren’t as strong as for older individuals or those with underlying health conditions, and said that the authorization implies “smoke and mirrors and underhanded winks and nods.”
Long, however, ultimately voted in favor of a booster after members discussed the need to include specific reminders to doctors in the accompanying fact sheets and clinical guidance that will be distributed. In particular, this information will caution that the need for a booster, especially among younger people, should be carefully weighed against rare but known side effects, which include inflammation of the heart tissue in the case of the mRNA vaccines, and blood clots and Guillain-Barre Syndrome for the J&J-Janssen shot.
Data presented from the vaccine manufacturers and evaluated by the FDA and CDC showed that the mRNA vaccines continue to provide good protection against severe COVID-19 disease, although their ability to protect people from getting infected in the first place is waning. So the unanimous decisions reflected the fact that the committee members accepted that the authorization would mean some people who would be getting boosters might not actually need them from a purely immunological point of view but that from a pubic health perspective, authorizing the booster to ensure that people can protect themselves in whatever way they can against the ongoing pandemic takes precedence over that.
With the recommendation, it now falls to providers—pharmacists, doctors, community health care workers and school nurses—to figure out how to roll out booster doses. After the Pfizer-BioNTech booster authorization, Walensky noted that most vaccinators will be relying on people to self-attest that they fall into one of the eligible groups, and that they won’t be requiring documentation or other proof of medical conditions or age.
Administering the boosters will be complicated, since Moderna’s booster is a half dose, and both patients and doctors will likely try to game the one study that evaluated so-called mixing and matching of boosters to figure out which one will provide the greatest protection. The panel members heard from the co-lead researcher of that study, conducted by the National Institute of Allergy and Infectious Diseases, who stressed that the trial was not designed to compare different combinations, but rather to show that mixing boosters was both safe and efficacious. Still, that data, which included more than 450 people, suggested that those who were originally vaccinated with a single dose of J&J-Janssen’s shot enjoyed the greatest increase in protection in the form of virus-fighting antibodies if they received a Moderna booster. The panel members also discussed the fact that given the risk of clotting events, especially among younger women vaccinated with J&J-Janssen, providers might consider boosting this population with an mRNA vaccine.
Complicating matters further is the fact that in August, the FDA and CDC authorized a third dose of the mRNA vaccines for people with weakened immune systems, including cancer patients, those who have had organ transplants or are taking drugs that suppress their immune systems. Those doses are not considered booster doses but an additional dose to bolster their immune systems as part of their primary vaccination against COVID-19. The committee discussed that under the current booster authorization these patients too would be eligible for booster shots at the appropriate time, which would mean a fourth dose for people originally vaccinated with an mRNA shot and a third dose for those getting J&J-Janssen.
Dr. Grace Lee, chair of the ACIP committee, said that it’s up to providers to educate themselves and the public about the complicated booster recommendations, and to make sure that those who really need them get them and benefit from the enhanced protection. “Our recommendation is just one step along the way,” she said. “It’s important for us to make sure in our implementation that patients are truly educated about the benefit-risk balance based on their own personal situation. It’s the hardest thing for us to do, but I encourage all of us to go beyond these recommendations and do our best to educate our communities and provider teams, and partner with public health.”
The fact that mixing doses appears to be both safe and efficacious could help support the U.S. government’s booster campaign as well. Smaller doctor’s offices or community clinics, or mobile units that go into long-term care facilities, for example, won’t have to store all three vaccines, but instead could focus on one, streamlining the logistics of their vaccination efforts. The White House has said it has purchased the necessary supply of booster doses and is prepared to ship them now that the FDA and CDC have authorized them.