Pfizer and BioNTech’s clinical trial for third ‘booster’ vaccine shot, talk of variant-specific mRNA vaccine is underway - DPF

Article Details

messenger Ask Dr. Patrick Flynn Right Arrow
article image

Pfizer and BioNTech’s clinical trial for third ‘booster’ vaccine shot, talk of variant-specific mRNA vaccine is underway

Story at a glance

  • On February 25, 2021, Pfizer and BioNTech announced they will be launching a new clinical trial.
  • They are exploring the possibility of adding a third ‘booster’ dose of their COVID-19 vaccine, which would be received 6-12 months after receiving the original two-dose regimen.
  • The third dose would be additional coverage against evolving variants of SARS-CoV-2.
  • In a separate matter, Pfizer and BioNtech revealed they have been discussing the possibility of creating a variant-specific vaccination with regulatory authorities (FDA and European Medicines Agency).
  • The new vaccine would not require a lengthy or thorough clinical trial, per the FDA’s updated guidelines regarding vaccines for SARS-CoV-2 variants.
  • This statement was released approximately two weeks after scientists called for the government to invest in a $100 million-$200 million research trial which would explore the idea of a ‘pan-virus vaccine’.

Press Release

On February 25, 2021 Pfizer and BioNTech announced they will be launching a new clinical trial. Their press release details that they intend to measure the effectiveness of adding a third ‘booster’ shot of their COVID-19 vaccine to their 2-shot regimen.

The statement says, “The study will draw upon participants from the Phase 1 study in the United States who will be offered the opportunity to receive a 30 µg booster of the current vaccine 6 to 12 months after receiving their initial two-dose regimen. The study is part of the companies’ clinical development strategy to determine the effectiveness of a third dose against evolving variants.”(1)

The companies are also considering the invention of a variant-specific vaccine to combat variants, the press release states.

It says, “Separately, in order to be prepared for any potential future strain changes, Pfizer and BioNTech are in ongoing discussions with regulatory authorities, including the U.S. Food and Drug Administration (FDA) and the European Medicines Agency, regarding a registration-enabling clinical study to evaluate a variant-specific vaccine having a modified mRNA sequence.” (2)

The press release mentions that they intend to construct the new vaccine based on the B.1.351 lineage (initially identified in South Africa).

Updated guidance issued by the FDA

On February 22, 2021, the FDA released updated guidance regarding the evaluation of vaccines for emergency use.

The update of the original guidance from October 2020 states that the clinical trials investigating vaccines which target COVID-19 variants would not have to be large-scale.

The press release from Pfizer and BioNTech references the updated guidance and says, “the companies are hoping to pursue the validation of future modified mRNA vaccines with a regulatory pathway similar to what is currently in place for flu vaccines.” (3)

The FDA’s released update says that “A determination of effectiveness should be supported by conducting clinical immunogenicity studies.” (4)

These clinical studies are expected to be smaller so that results are determined faster.

Scientists call for ‘pan-virus vaccines’

Approximately two weeks before Pfizer and BioNTech issued their press release, scientists from Scripps Research Institute in San Diego, CA, released a commentary in Nature calling for the government to invest $100-$200 Million in a new ‘pan-virus vaccine’. The article is titled “Variant-proof vaccines— invest now for the next pandemic”.

The article starts by calling the “rapid development and delivery” of COVID-19 vaccines a “huge success story”.

Although the press release from Pfizer and BioNTech says they have no evidence that their vaccine is ineffective in terms of SARS-CoV-2 variants, this article counteracts this statement.

The scientists say that “laboratory studies suggest the potential for immune escape with at least one of these [SARS-CoV-2] variants.” (5)

The commentary seems to be critical of the government’s ill-preparedness for a pandemic. They believe that the next pandemic will involve ‘evasion-strong’ pathogens and that the only way to defeat them will be with a silver bullet vaccine.

This will not be an easy feat, though. The scientists say, “Generating very broad, very potent neutralizing antibodies can be difficult” but that “compromises can be made, and methods for delivering cocktails of antibodies (two or three, say) and vaccines are becoming feasible.” (6)

Their approach involves the use of a “special class of protective antibodies called broadly neutralizing antibodies” which are reported to act against many different strains of related virus.

A third dose, a variant-specific, and a pan-virus vaccine…

At the end of the day, these vaccines come from the public fear of SARS-CoV-2 variants. There is still not enough substantial evidence that the interventions already in place are insufficient or ‘lacking’.

The commonality between them all, though, is that they disregard the individualities of the recipients. There is no prediction of how an additional dose, a modified mRNA sequence, and a “cocktail of antibodies” will impact the future of health.

Further Discussion