What is unique about the mRNA vaccine BNT162b2 being developed by Pfizer? How is it different from the other vaccine candidates?
Our BNT162 programme is based on [German company] BioNTech’s proprietary mRNA-based technology, a novel platform that provides efficiency and flexibility that is apparent by the pace of the vaccine development and the unprecedented trial design that it supports. We believe mRNA-based vaccines are promising because of their potential for high potency, safe administration and capacity for rapid development and manufacturing, a critical factor given the timing and scale needs posed by this pandemic. Unlike conventional vaccines, which can take months to produce by growing weakened forms of the virus, RNA vaccines can be constructed quickly using only the pathogen’s genetic code. No virus is needed to make a batch of an RNA vaccine. Only small quantities of the virus are used for gene sequencing and vaccine testing.
How many volunteers are involved in the trial?
As of November 16, Pfizer’s Phase 3 study has enrolled 43,661 participants and approximately 42 per cent from racially/ethnically diverse backgrounds. We have more than 120 investigator sites in four countries (Argentina, Brazil, South Africa and the US), including 39 American states.
How effective is the vaccine?
Data from our large Phase 3 study of nearly 44,000 people has demonstrated that our vaccine candidate is 95 per cent effective in helping to prevent Covid-19, beginning 28 days after the first dose. Of the 170 Covid-19 cases reported, 162 were in the placebo group, and only eight in the vaccine group. This means that most infection cases come from those who received a placebo, rather than the vaccine immunisation. Pfizer said that the vaccine's efficacy was consistent across age, gender, race and ethnicity.
What is the estimated timeline?
Based on current projections, we expect to produce up to 50 million vaccine doses in 2020 and up to 1.3 billion doses in 2021. If our vaccine candidate is successful, we would allocate doses proportionally across the countries where we have fully executed supply agreements that include delivery of a portion of doses in 2020. The company plans to apply to the FDA for Emergency Use Authorisation within days.
How many shots may be needed to achieve immunity?
It is two doses of 30μg of BNT162b2.
Any safety concerns?
Safety was, is, and will always be our number one priority in vaccine research and development. Even though Pfizer is moving with extraordinary speed, preservation of high quality and safety standards is critically important throughout the development. The trial’s progress is closely monitored by both Pfizer and an independent external DMC. Trial investigators are also responsible for monitoring the participants’ health, and participants in the trial have regular planned follow-up visits as part of the trial. Additionally, participants will continue to be monitored for long-term protection and safety for an additional two years after their second dose. No serious safety concerns have been observed to date. The only other side effects reported were fatigue and headache, 3.8 per cent and 2.0 per cent respectively.