Feb 25, 2021 - Health

Pfizer begins study on 3rd vaccine dose as booster shot against new variants

Picture of Pfizer-BioNTech COVID vaccine vials

Photo: Pete Bannan/MediaNews Group/Daily Local News via Getty Images

Pfizer and BioNTech on Thursday announced they have launched a study to evaluate whether a third dose of their COVID-19 vaccine can protect against new variants of the virus.

Why it matters: Vaccine makers are racing to find effective ways to fight more infectious virus variants. There is no evidence that the current vaccines are not effective against the new variants, but companies are looking for ways to adapt to new mutations in case it becomes necessary.

  • Unlike Pfizer, Moderna made a modified vaccine targeting the South Africa strain and shipped doses to U.S. government researchers to begin testing.
  • Oxford and AstraZeneca said that a new version of their vaccine to fight the highly infectious South Africa variant could become available in the fall.

Details: Pfizer and BioNTech will offer a third vaccine dose to 144 people who received two doses in the early-testing stages and were vaccinated six months to a year ago.

  • Participants will be between the ages of 18 and 55, as well as 65 through 85.
  • Researchers will evaluate the participants' ability to neutralize new strains at the time they receive the dose, a week later, and and a month later. The participants will also continue to be studied for up to two years.
  • The companies did not say when results could be expected, but Pfizer R&D chief Mikael Dolsten said results could come around early summer during an earnings call, The Wall Street Journal reports.

Worth noting: Pfizer and BioNTech said they were in discussion with the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) in case a new vaccine version would be necessary to protect against the South Africa strain.

  • But, but, but: Experts told STAT that since the variants were not completely resistant to the vaccine, a new booster dose should be enough to offer more protection.

Go deeper: FDA says modified vaccines for COVID variants would not require large clinical trials

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