For immunocompromised people who have received a single injection of Johnson & Johnson’s coronavirus vaccine, the CDC does not recommend supplemental primary doses, but advises that they receive a booster shot of the Moderna or Pfizer-BioNTech vaccines two months after the first dose. .
Some people are born with an absent or defective immune system, and in others, treatments for some diseases such as cancer reduce the potency of the immune defenses. The CDC estimates that there are approximately seven million immunocompromised individuals in the country.
Many of them produce little to no antibodies in response to a vaccine or infection, making them susceptible to the virus. If they become infected, they can become ill for a long time, with a death rate of as much as 55 percent.
It’s unclear what proportion of those people are protected by additional doses. Still, with the rise of the Omicron variant in the country, some immunocompromised people sought fourth or even fifth injections of the vaccines even before the CDC changed its guidelines. While receiving multiple doses of vaccines in a short period of time is unlikely to be harmful, some experts say it may have diminishing returns.
The CDC has said that any American age 12 and older can receive a Pfizer-BioNTech booster — those 18 and older can also receive a Moderna booster — five months after completing their first injections of those vaccines. Israel has already started offering fourth doses to high-risk groups, including older adults. But the Biden administration has not yet said whether it plans to follow suit.
When asked Friday about the possibility of a fourth shot to the general population, Dr. Rochelle Walensky, director of the CDC, that continued to focus on Americans qualifying for their third shot.
She added that US officials remained in close contact with Israeli experts about their data. “We will also be following our own data carefully to see how these boosters work in terms of diminishing effectiveness, not just for infection but, more importantly, for serious disease,” she said.