Half-Dose of COVID-19 Booster Just as Effective as a Full Dose: Study

The study also found fewer side-effects from a half-dose compared to a full dose.
Half-Dose of COVID-19 Booster Just as Effective as a Full Dose: Study
Jessie Zhang

Reducing the dose of a Pfizer COVID-19 booster vaccine can elicit a comparable immune response in adults compared to a full dose with fewer side effects, new research has found.

Led by the Murdoch Institute and the National Centre for Communicable Diseases in Mongolia, the study is the first to assess and compare widely used COVID-19 vaccines in low- and middle-income countries.

The research involved 601 participants over 18 years old from Mongolia who had previously received AstraZeneca or Sinopharm COVID-19 shots.

Murdoch Institute’s Professor Kim Mulholland said they found that reduced doses of the Pfizer booster produced a non-inferior immune response.

“Fractional dosing may improve COVID-19 booster acceptability and uptake and reduce the per-dose cost of COVID-19 booster programs,” he said.

“Policymakers and immunisation advisory committees can draw upon this data to make flexible boosting schedules decisions.”

However, the study noted that half-dose boosting may be less effective in adults primed with the Russian COVID-19 vaccine, Sputnik V.

Fewer Side Effects for Half Doses

Participants receiving half doses reported fewer side effects compared to those receiving full doses, highlighting the potential benefits of this approach.

Among half-dose boosted participants, 60 percent reported local reactions including pain and tenderness, and 25 percent reported systemic reactions including fevers, vomiting, diarrhoea, and headaches.

On the other hand, 72 percent of full-dose boosted participants reported local reactions, and 32 percent reported system reactions.

The study will continue to follow up on participants at six and 12-month intervals to explore their immune response, such as waning rates and breakthrough infections.

FDA Vaccine Adviser: Most Don’t Need Yet Another COVID-19 Booster

This comes amid recommendations from the Food and Drug Administration’s (FDA) vaccine adviser Dr. Paul Offit that most people did not need another COVID-19 booster.

In an article in a medical journal, he said that asking young, healthy people to get boosted with a variant-specific booster was pointless.

“I believe we should stop trying to prevent all symptomatic infections in healthy, young people by boosting them with vaccines containing mRNA from strains that might disappear a few months later,” Dr. Offit wrote in the paper.

Medical researcher and immunology specialist Kevin Bass echoed his sentiment saying people were likely to take a hard pass on the new COVID-19 booster shot unless it was mandated.

“Public opinion has swung so hard against the vaccines that I can’t imagine a scenario where a significant amount of people are going to sign up for another shot,” he told The Epoch Times in a recent interview. “If people have the choice, they are going to say no.”

Global Trial Investigating Reduced COVID-19 Boosters

The new research was published in the Lancet, and is part of an international clinical trial funded by the Coalition for Epidemic Preparedness Innovations (CEPI).

This trial, involving 3,300 healthy adults across Australia, Indonesia, and Mongolia, investigates the impact of administering a reduced dose of COVID-19 booster shots.

The efficacy, side effects, and acceptability of fractional doses explored will inform flexible booster strategies and address global vaccine supply challenges.

CEPI receives funding from the Australian government.