U.S. FDA authorizes COVID-19 vaccine boosters for those with weak immune systems

The U.S. Food and Drug Administration on Thursday authorized a booster dose of COVID-19 vaccines from Pfizer-BioNTech and Moderna for people with compromised immune systems.

The amended emergency use authorization on Thursday paves the way for people who have had an organ transplant, or those with a similar level of weakened immune system, to get an extra dose of the same shot they have initially received. Mixing of mRNA vaccines is permitted for the third shot if their original vaccine is not available.

An advisory panel to the U.S. Centers for Disease Control and Prevention (CDC) on Friday voted to recommend the additional doses, an important step before the policy is implemented.

Patients will not need a prescription or the sign-off of a health-care provider in order to prove they are immunocompromised and receive the additional dose, according to CDC officials.

"It will be a patient's attestation, and there will be no requirement for proof or prescription or a recommendation from an individual's health care provider," CDC official Dr. Amanda Cohn said.

Applies only to 2-shot vaccines for now

The FDA's decision does not apply to people who received the one-dose Johnson & Johnson vaccine, the CDC said, because there is not enough data to support additional doses yet.

"We think that at least this is a solution for the very large majority of immunocompromised individuals, and we believe that we'll probably have a solution for the remainder in the not-too-distant future," FDA official Peter Marks told the CDC panel.

The FDA and the CDC are working to ensure that immunocompromised recipients of the J&J vaccine have optimal protection, the CDC said.

Spurred by the delta variant, coronavirus cases in the United States have spiked to their highest levels in more than six months, according to a Reuters tally.

The vulnerable group makes up less than 3 per cent of U.S. adults, Rochelle Walensky, CDC director, had said before the authorization, which translates to about 10 million Americans.

A few other countries, such as Israel and Germany, plan to or have already administered the third shot to avoid another crisis due to the contagious Delta variant of the coronavirus.

In Canada, the National Advisory Committee on Immunization (NACI) told CBC News in a statement that it "continues to closely monitor emerging evidence concerning the effectiveness of COVID-19 vaccines in those who are immunosuppressed, including evidence on the potential need or benefit of a third dose in this population."

The statement also said NACI would be updating its recommendations in the coming weeks.

Questions of inequity, necessity

Scientists are still divided over the broad use of COVID-19 vaccine boosters among those without underlying problems as benefits of the boosters remain undetermined.

Pfizer has said the efficacy of the vaccine it developed with BioNTech drops over time, citing a study that showed 84 per cent effectiveness from a peak of 96 per cent four months after a second dose.

Moderna has also said it sees the eventual need for booster doses, especially since the delta variant has caused "breakthrough" infections in fully vaccinated people.

Reports of infections among vaccinated people and concerns about diminishing protection have galvanized wealthy nations to distribute booster shots, even as many countries struggle to access first vaccine doses. The World Health Organization last week called for a moratorium on COVID-19 vaccine booster shots.

Pfizer, along with its German partner BioNTech, and Moderna have together locked up over $60 billion US in sales of the shots just in 2021 and 2022. The agreements include supply of the initial two doses of their vaccines as well as billions of dollars in potential boosters for wealthy nations.

Going forward, analysts have forecast revenue of over $6.6 billion for the Pfizer-BioNTech shot and $7.6 billion for Moderna in 2023, mostly from booster sales.