Dr. Jose U. Scher, a rheumatologist at NYU Langone Health who has studied the effect of vaccines on the immunocompromised, said that the C.D.C. vote — and the guidance from its experts — would help patients who had been agonizing over whether to seek out a third shot. Previously, he said, when people tested themselves for antibodies after vaccination and came up empty, “there were no tools for us to respond to that.”
“We now know that this population was being left behind,” he said.
Immunocompromised people will not need a doctor’s permission or a prescription to get a third shot, C.D.C. officials said. They will need only to attest that they meet the eligibility requirements for an additional dose. Anyone else, including people with chronic medical conditions, like diabetes or asthma, should not be getting third shots at this point, they said.
Dr. Scher predicted that this honor-system approach could be messy. “I don’t know if there’s any way of corroborating someone’s claim” of being immunocompromised, he said. Requiring some kind of proof, such as a doctor’s note, would be a better process, he said.
The updated F.D.A. authorizations do not apply to immunocompromised people who received the single-dose Johnson & Johnson vaccine. The C.D.C. panel did not offer recommendations on additional shots for that group, which is believed to be small. But the lack of guidance from either the F.D.A. or C.D.C. has left that group in limbo.
Understand the State of Vaccine and Mask Mandates in the U.S.
- Mask rules. The Centers for Disease Control and Prevention in July recommended that all Americans, regardless of vaccination status, wear masks in indoor public places within areas experiencing outbreaks, a reversal of the guidance it offered in May. See where the C.D.C. guidance would apply, and where states have instituted their own mask policies. The battle over masks has become contentious in some states, with some local leaders defying state bans.
- Vaccine rules . . . and businesses. Private companies are increasingly mandating coronavirus vaccines for employees, with varying approaches. Such mandates are legally allowed and have been upheld in court challenges.
- College and universities. More than 400 colleges and universities are requiring students to be vaccinated against Covid-19. Almost all are in states that voted for President Biden.
- Schools. On Aug. 11, California announced that it would require teachers and staff of both public and private schools to be vaccinated or face regular testing, the first state in the nation to do so. A survey released in August found that many American parents of school-age children are opposed to mandated vaccines for students, but were more supportive of mask mandates for students, teachers and staff members who do not have their shots.
- Hospitals and medical centers. Many hospitals and major health systems are requiring employees to get a Covid-19 vaccine, citing rising caseloads fueled by the Delta variant and stubbornly low vaccination rates in their communities, even within their work force.
- New York. On Aug. 3, Mayor Bill de Blasio of New York announced that proof of vaccination would be required of workers and customers for indoor dining, gyms, performances and other indoor situations, becoming the first U.S. city to require vaccines for a broad range of activities. City hospital workers must also get a vaccine or be subjected to weekly testing. Similar rules are in place for New York State employees.
- At the federal level. The Pentagon announced that it would seek to make coronavirus vaccinations mandatory for the country’s 1.3 million active-duty troops “no later” than the middle of September. President Biden announced that all civilian federal employees would have to be vaccinated against the coronavirus or submit to regular testing, social distancing, mask requirements and restrictions on most travel.
“We do understand the challenges here, and because of that we will continue to work very diligently to try to have a solution,” Dr. Peter Marks, the F.D.A.’s top vaccine regulator, said at the panel’s meeting. The F.D.A. is waiting on more data that it expects to receive this month, including Johnson & Johnson’s clinical trial data on the safety and efficacy of two doses.
Dr. Kathleen Dooling, a C.D.C. official, said that patients who qualify for a third dose should ideally seek out the vaccine they already received, but that they could take the other two-dose vaccine if necessary.
Presenting studies that supported giving third doses, Dr. Dooling emphasized that immunocompromised people who receive a third dose should still wear a mask, maintain social distancing with people they do not live with, and avoid crowds and poorly ventilated indoor spaces. She said that people with weakened immune systems had also been shown to be at greater risk of breakthrough infection.