Multinational drug company Pfizer has announced promising results from its ongoing phase-3 trial of a potential COVID-19 vaccine. However, these early results, of the vaccine candidate being “90% protective” in the trial’s volunteers — nearly 40,000 are enrolled — is the only important detail that is public. Pfizer, which is using a vaccine candidate by German firm BioNTech, had disclosed in September that for a vaccine to be judged 60% effective, 164 volunteers would have to contract COVID-19. This includes both the vaccine and placebo groups. The claim of 90% is based on a sample of 94 volunteers but it is not known how many belonged to either group. It is also unclear if those who were eventually infected, manifested mild or moderate severity of disease. Though the results, according to Pfizer, were announced by an expert independent committee, they have not yet been announced by the standard procedure of a peer-reviewed journal. In short, there is still time to be reliably sure that the results actually hold up in a wider population.
Pfizer’s announcement may not have an immediate impact for India. Unlike ‘Covishield’ by the Serum Institute or ‘Covaxin’ by Bharat Biotech Ltd., there are no large phase-3 trials of the vaccine in India. While there were early discussions with Pfizer, there is as yet no confirmation on whether India can be assured of early access to even a fraction of the vaccine output in the event it is readied. The vaccine candidate is based on an m-RNA technology, which eschews the use of an infectious particle, such as a portion of the virus, and uses a piece of RNA that is then made into an antigen by the body’s own machinery. This reduces the odds of untoward reactions. It also does not need to be cultured in chicken eggs or other mammalian cells, allowing it be made faster and more inexpensively. Though it is at the frontier of novel vaccine production methods, there are still no commercially available m-RNA based vaccines. They also reportedly need to be refrigerated to nearly minus 70°C and India, with its limited cold chain infrastructure, lacks efficient vaccine storage capacity. However, irrespective of whether and when the Pfizer vaccine is available, there is reason for optimism. For one, it shows that scientists’ basic strategy — of developing a vaccine to target the spike protein of the virus — is correct and given that this is an approach most vaccine developers are following, the chances of several encouraging results are high. Given that another firm, Moderna, also employs an m-RNA based approach, it is likely that the new vaccine platform may prove to be a breakthrough approach in developing future vaccines. India must keep a close watch on such platform-technology and develop expertise. It must also not lose an opportunity to improve its cold chain infrastructure which currently is developed only for rudimentary vaccines.