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Thursday, September 24, 2020

Pfizer Covid-19 vaccine: what trials have found, and the implications of the results

Project Lightspeed: The study, which is yet to be peer-reviewed, said that across all populations, the candidate was well-tolerated and demonstrated a strong immune response, and that they are on track to seek regulatory review in October 2020.

Written by Kaunain Sheriff M | New Delhi | Updated: August 24, 2020 9:03:30 am
covid vaccine, coronavirus vaccine, covid vaccine India, India covid vaccine, Explained health, Express Explained, Indian Express"Until you actually have efficacy data on a vaccine, it is impossible to say whether a vaccine will work in humans or not," says Dr Kang.

US Pharma giant Pfizer and German biotechnology company BioNTech’s, which are testing four vaccine candidates for Covid-19 as part of Project Lightspeed, released on Thursday the phase-1 data for one of these, being tested in the US. The study, which is yet to be peer-reviewed, said that across all populations, the candidate was well-tolerated and demonstrated a strong immune response, and that they are on track to seek regulatory review in October 2020.

What is Project Lightspeed?

The project with four vaccine candidates is based on BionTech’s proprietary mRNA-based technology platforms. It began in mid-January after the genetic sequence of SARS-CoV-2 was made public.

Two of these four candidates — BNT162b1 or BNT162b2 — have gone into human trials so far. Both are in Phase 1/2 human trials in the United States and Germany.

How have the trials progressed?

On April 23, 12 participants in Germany were dosed with either of the two vaccines. On May 5, the first participants in the United States were given a dose of either vaccine.

On July 13, BNT162b1 and BNT162b2 received a fast-track designation from the US Food and Drug Administration (FDA).

On July 27, researchers announced that after extensive review of preclinical and clinical data and in consultation with the US FDA’s Center for Biologics Evaluation and Research , they have chosen to advance their BNT162b2 vaccine candidate into the Phase 2/3 study, where 30,000 participants will be taking part.

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What is BNT162b2?

It is a single nucleoside-modified messenger RNA (modRNA) vaccine candidate. It is made of a short segment of genetic material — the messenger RNA — which provides instructions for a human cell to make a harmless version of a target protein, in this case the spike protein of SARS-CoV-2, in order to activate an immune response against the protein.

During a clinical trial, three aspects are assessed: reactogenicity (ability to produce common, adverse reactions), immunogenicity (ability to provoke an immune response), and safety.

In phase 1 in the US, at 7 days after the second dose of 30 micrograms, the candidate demonstrated strong immunogenicity in both younger and older adults when compared to levels found in a convalescent serum panel (the serum obtained from one who has recovered), states the study on Thursday.

Key vaccine candidates, trial findings

Also read Covid-19 vaccine tracker, August 22: The latest news from the field of vaccines

Why has this candidate been advanced into Phase 2/3 trials?

On July 20, Pfizer had announced that BNT162b1 elicited a strong T cell response in its German trial. About BNT162b2, it said cellular immune responses “are still being studied and will be reported separately”.

On Thursday, the study concluded that in both younger and older adults, by BNT162b1 and BNT162b2 elicited similar immune responses. However, BNT162b2 was associated with less systemic reactogenicity, particularly in older adults. This effectively means that BNT162b2 generates an even lower adverse reaction among the vulnerable population, making it the safer candidate of the two.

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How significant are the findings?

The findings are significant as Pfizer plans to activate its extensive manufacturing network and “invest at risk” to produce the vaccine. The company has said it will manufacture up to 100 million doses by the end of 2020 and potentially more than 1.2 billion doses by the end of 2021.

The pharmaceutical giant had already identified three US states — Massachusetts, Michigan, and Missouri —where it will manufacture the vaccine in its own facilities. It will also manufacture it in Puurs, Belgium. After the results, the company said it will select more sites for production. It already has signed deals with various countries.

Simultaneously, through its existing mRNA production sites in Mainz and Idar-Oberstein in Germany, BioNTech plans to ramp up its production capacity to provide further capacities for a global supply of the potential vaccine.

Which countries will be buying the vaccine, if cleared?

On July 20, the company announced an agreement with the UK to supply 30 million doses. Two days later, it announced that the US government has placed an initial order of 100 million doses for $1.95 billion and can acquire up to 500 million additional doses. On July 31, the company announced an agreement with Japan’s Ministry of Health, Labour and Welfare to supply 120 million doses. On August 5, it announced another agreement, with the Government of Canada.

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