A third
dose might help better protect some, but the CDC is still deciding on official
guidance
People
with weak immune systems don’t always mount strong defenses against the
coronavirus, even after being fully vaccinated. A third COVID-19 vaccine dose
might help protect some immunocompromised people, evidence suggests. But for
now, there’s not enough data to say how much such a shot might help, experts
with the U.S. Centers for Disease Control and Prevention said July 22. As a
result, the agency isn’t yet recommending a third dose and says that vaccinated
people in this group should keep wearing masks.
With
global COVID-19 cases on the rise, finding ways to protect millions of
immunocompromised people who are at high risk for severe disease is crucial. In
the United States, an estimated 2.7 percent of adults, or 6.8 million people,
are immunocompromised.
Studies
suggest that until transmission of the coronavirus is squashed, millions of
organ transplant recipients, cancer patients undergoing treatment and others
are still susceptible to severe COVID-19, even if they are lucky enough to have
access to shots (SN: 2/26/21). Of 45 vaccinated people admitted to 18 U.S.
hospitals for COVID-19 from March 11 to May 5, twenty, or 44 percent, were
immunocompromised, according to data presented in a July 22 meeting of the
CDC’s Advisory Committee on Immunization Practices.
A third
dose of COVID-19 vaccines can boost coronavirus-fighting antibodies in the
blood of some immunocompromised patients, laboratory studies suggest. But it’s
still unclear whether specific groups might benefit more than others and how
effective extra doses might be at preventing severe COVID-19. The immune
system, for instance, has more than antibodies in its arsenal to attack the
coronavirus and prevent severe disease (SN: 1/27/21). Studies from the real
world would provide a clearer picture for how well additional doses might work,
and for which groups.
At the
very least, an additional dose appears safe for immunocompromised individuals,
epidemiologist Sara Oliver of the CDC said at the July 22 meeting. For example,
a study that included patients on dialysis for kidney disease showed that
“symptoms reported after the third dose were consistent with what has been seen
after the second dose,” Oliver said. Most vaccine side effects — such as
fatigue, pain at the injection site, chills or soreness — were mild.
While
U.S. officials are still discussing the benefits of the additional dose, some
countries have already taken steps to get those doses to immunocompromised
residents. Severely immunocompromised people in France, for instance, can get a
third dose a month after their second dose, officials announced April 11.
Officials in Israel announced July 11 that they too would begin giving
immunocompromised individuals a third shot. And officials in the United Kingdom
have proposed distributing additional doses between September and December.
In the
United States, a recommendation for an additional dose for immunocompromised
people probably won’t come unless the Food and Drug Administration permits
extra doses under current emergency use authorizations for COVID-19 vaccines or
until the agency fully approves the vaccines for widespread use, CDC officials
said during the meeting. For now, the health agency isn’t aware of any data
submitted to the FDA that might support such a change to the emergency use
authorizations, the officials said.
In the
meantime, experts are keeping a close eye on emerging data about additional
doses. “However, while we do that, we need to remember what we can do now,”
Oliver said. That means immunocompromised people should continue to wear masks,
stay six feet away from others and avoid crowds or indoor spaces.
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