- BNT162b2 is a vaccine that has been developed using mRNA technologye. it makes use of the messenger RNA molecules that tell cells what proteins to build.
- The mRNA, in this case, is coded to tell the cells to recreate the spike protein of the novel coronavirus.
- The coronavirus spike protein is a molecular machine that facilitates the entry of coronavirus into host cells.
- Once the mRNA is injected into the body, the cells use its instructions and create copies of the spike protein.
- This is expected to prompt (induce) the immune cells to create antibodies to fight the virus.
Advantages of mRNA vaccines:
- Unlike several other vaccine candidates, mRNA vaccines are synthetically developed i.e. they don’t need the virus to be cultivated and replicated.
- mRNA vaccines can be manufactured at a large scale in large vats (tanks) called bioreactors.
- After getting the code for the virus, it is possible to develop the mRNA vaccine within weeks for pre-clinical testing, compared with months taken for more traditional platforms.
Findings of the interim analysis based on phase 3 clinical trials
- According to the findings, the vaccine was more than 90% effective in preventing Covid-19 among participants who had received a second dose compared to those participants who had only received a placebo.
- Thus, the results demonstrate that Pfizer’s vaccine can help prevent Covid-19 in majority of people who receive it.
- The data also shows that there were no serious safety concerns.
- However, the analysis did not provide details on the specifics of the immune response, adverse reactions, and age-specific effectiveness of the vaccine.
Significance of the findings:
- Several international regulators and health organisations have suggested that a Covid-19 vaccine to be effective, the vaccine has to protect at least 50% of the people who receive it.
- Based on this, the current findings are a positive sign in the development of a safe and effective vaccine.
Emergency use authorisation:
- The current findings of the vaccine are based on only 94 out of nearly 40,000 volunteers who have been injected the vaccine. Thus, more data on the effectiveness of the vaccine and its safety is needed.
- Pfizer and BioNTech have informed that they will accumulate this additional data (by end November), after which they will be able to apply for emergency use authorisation from the American regulator, the United States Food and Drug Administration (FDA)
Global arrangements for distribution:
- Pfizer has said, it would manufacture up to 100 million doses of the vaccine by the end of 2020, and potentially more than 2 billion doses by the end of 2021.
- It has so far announced agreements to supply hundreds of millions of doses of vaccine to countries including the US, United Kingdom, Japan, and Canada.
Possibility of the vaccine availability in India
- As of now, Pfizer does not have an agreement with the Indian government, and has not identified any manufacturing facility in India.
- As per India’s regulatory requirements, a vaccine would have to undergo local trials in the country before it can receive an approval for a launch.
- Pfizer’s mRNA vaccine candidate requires storage and shipping in sub-zero (below zero) temperature conditions.
- The 28,000-unit cold storage network that India’s universal immunisation programme uses, currently handles temperatures in the range of 2-8 degrees Celsius. Due to this, there will be logistical issues in the delivery of this vaccine in India.
- Thus, for the vaccine to be delivered effectively in India, an appropriate ultra-cold storage infrastructure will have to be set-up.