Coronavirus: What does it mean to be immunocompromised?

The Food and Drug Administration on Thursday authorized a third dose of Pfizer-BioNTech’s and Moderna’s coronavirus vaccines for people suffering from weakened immune systems.

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The agency’s authorization of a third shot of the vaccine is aimed at adults considered immunocompromised, or people who have weakened immune systems due to genetic conditions, disease or the use of certain medications.

The authorization targets those who had received a solid organ transplant or individuals who have been diagnosed with conditions that leave them with an equivalent level of immunocompromise.

The FDA determined the immunocompromised can receive a third dose of the vaccines from Pfizer and Moderna at least 28 days after getting their second shot. The FDA made no mention of immune-compromised patients who received the single-dose Johnson & Johnson vaccine.

Around 3% of the U.S. population, or 7 million people, is considered immunocompromised. In announcing the decision to make a third shot available to those with weakened immune systems, acting FDA commissioner Dr. Janet Woodcock said research had shown a benefit in an additional dose of mRNA COVID-19 vaccine.

“The FDA is especially cognizant that immunocompromised people are particularly at risk for severe disease,” Woodcock, said in a statement.

“After a thorough review of the available data, the FDA determined that this small, vulnerable group may benefit from a third dose of the Pfizer-BioNTech or Moderna vaccines.”

“Today’s action allows doctors to boost immunity in certain immunocompromised individuals who need extra protection from COVID-19. As we’ve previously stated, other individuals who are fully vaccinated are adequately protected and do not need an additional dose of COVID-19 vaccine at this time. The FDA is actively engaged in a science-based, rigorous process with our federal partners to consider whether an additional dose may be needed in the future.”

The Centers for Disease Control and Prevention’s Advisory Committee for Immunization Practices is expected to meet Friday to determine specifics about who should get the booster.

If the committee votes to endorse the shots, the CDC could issue a recommendation on Friday that would clarify who would benefit from a third shot and who should get one.

Who is considered immunocompromised and what does this mean for the potential of a third shot for others?

Here is what we know about it now:

What does immunocompromised mean and why is it a risk?

Those who are considered immunocompromised have weakened immune systems which make it difficult to fight disease.

You can be immunocompromised because of a condition you are born with, from disease or from the use of certain medications.

According to the Centers for Disease Control and Prevention, having a weakened immune system puts you at a greater risk of becoming severely ill from the COVID-19 virus.

Who falls in that category?

From the CDC, examples of people with weakened immune systems include:

“Those with HIV/AIDS; cancer and transplant patients who are taking certain immunosuppressive drugs; and those with inherited diseases that affect the immune system (such as congenital agammaglobulinemia or congenital IgA deficiency). "

Will a third shot offer adequate protection for the immunocompromised?

Some argue that the immunocompromised population is too diverse to recommend additional shots of the COVID-19 vaccine for everyone, according to The New York Times.

However, a study headed by Dr. Dorry Segev, of the Bloomberg School of Public Health at Johns Hopkins University, showed benefits of a third dose for those with weakened immune systems.

Segev said that of 30 people who had little or no antibody response after two doses of an mRNA vaccine, 14 showed higher antibody levels following a third dose of either the Moderna or Pfizer vaccine.

Results from a Canadian study of those who have had organ transplants, also found that a third dose of the Moderna vaccine improved the immune response of people in that group.

If you are not immunocompromised, can you still get a booster? If not, when?

The third shot authorized on Thursday is aimed at helping those who have a weakened immune response to their initial vaccines. So far, the FDA emphasized it had not yet authorized a third shot for the general population.

According to Woodcock, those “fully vaccinated are adequately protected.”

Director of the National Institute of Allergy and Infectious Diseases and White House chief medical adviser Dr. Anthony Fauci on Thursday said that the decision over whether shots would be recommended for other groups has not yet been made.

“Apart from the immune-compromised, we don’t feel we need to give boosters right now.”

Later Fauci said that a booster shot would likely be required for everyone “sooner or later” to ensure that the durability of protection from COVID-19 vaccines continues.

“As we mentioned, we are evaluating this on a day by day, week by week, month by month basis, looking at any of a number of studies, both international and domestic studies,” Fauci said. “If the data shows us that, in fact, we do need to do that, we’ll be very ready to do it and do it expeditiously.”