A long-awaited ‘mix and match’ study of Covid-19 vaccines found the approach to be safe and effective, although Moderna and Pfizer-BioNTech vaccines were found to elicit a stronger immune system response than Johnson & Johnson.
Mixing and matching refers to the administration of a booster dose of a vaccine different from the type of vaccine used for the initial vaccination series.
The National Institutes of Health study, which was released on Wednesday and has not yet been peer reviewed, found that people who received the Johnson & Johnson vaccine produced stronger levels of antibodies after receiving an Moderna or Pfizer recall, versus Johnson & Johnson recall. Those who were initially vaccinated with the Pfizer or Moderna vaccines and received the booster from either company produced comparable immune responses, the researchers observed.
The results will be presented to the Food and Drug Administration’s advisory committee on Friday. The group is meeting Thursday and Friday to consider recommending authorization of a booster of Moderna and Johnson & Johnson vaccines.
The study, attributed to 37 doctors and academics, followed 458 volunteers and measured their antibody levels two weeks and four weeks after the boosters were given. The booster injections were given four to six months after the initial vaccinations.
Individuals were divided into different groups based on their original vaccinations and received one of three boosters made by Pfizer, Moderna or Johnson & Johnson. For example, those who were initially vaccinated with the two dose regimen of Pfizer received either a corresponding Pfizer booster or a “mix” from Moderna or Johnson & Johnson.
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