Some Americans can get four COVID-19 vaccine doses within less than a year, the Centers for Disease Control and Prevention (CDC) said this week.
U.S. drug regulators and the CDC recently cleared booster doses of all three COVID-19 vaccines authorized for use in the country.
The fourth dose would be for people who are either moderately or severely immunocompromised, or people with weakened immune systems, the CDC said in updated clinical guidance.
This population is allowed to get a third dose of a Pfizer or Moderna vaccine at least 28 days after their second dose. Both vaccines are built on messenger RNA technology and have a two-dose primary series.
The population can then get a booster six months or longer after their third dose, according to the CDC.
“In such situations, people who are moderately and severely immunocompromised may receive a total of four COVID-19 vaccine doses,” the agency says.
The scenario is completely different for Americans who got the single-shot Johnson & Johnson vaccine. Even if immunocompromised, they’re being told to only get one additional jab.
Additionally, people who do not have weakened immune systems are being warned not to get more than three doses of an mRNA vaccine.
The balance of benefits and risks of a fourth dose in the general population “is currently unknown,” the CDC says.
The immunocompromised population includes people with cancer, chronic kidney disease, and dementia.
The fourth dose availability comes about two weeks after the Food and Drug Administration (FDA) was questioned by its vaccine advisory panel on how clearing boosters would affect the previous authorization for an additional dose in the immunocompromised.
“This is far enough in the future that I don’t want to make a definitive statement here,” Dr. Peter Marks, an FDA official, said at the time.
Dr. Michael Kurilla, a panel member, said there was a potential for confusion regarding boosters if the guidance wasn’t clear.
Studies have found that people who have weakened immune systems benefit less from the COVID-19 vaccines than the general population, including one preprint paper that indicated the risk of being hospitalized or dying was 485 times higher for transplant recipients than other fully vaccinated persons.
The rate of COVID-19 infections among immunocompromised people who received two doses of Pfizer or Moderna’s shot, or the Johnson & Johnson jab, “also may be higher than the rate in vaccinated members of the general population,” the CDC said in a previous version of its clinical guidance.
Small studies have indicated that an additional dose, or a third dose, may enhance the antibody response in some of the population.
Still, “the exact correlation between antibody level and protection against severe COVID-19 outcomes as well as infectiousness remains unclear,” the CDC said.
COVID-19 is the disease caused by the CCP (Chinese Communist Party) virus.