Pfizer's Covid-19 Vaccine Candidate

• 10 Nov 2020

Why in News

Recently, American pharma company Pfizer has claimed that its vaccine candidate BNT162b2 is more than 90% effective in preventing Covid-19 in participants without evidence of prior SARS-CoV-2 infection.

Key Points

• BNT162b2:
  
  • It is a single nucleoside-modified messenger RNA (modRNA) vaccine, which is made of a short segment of genetic material (the messenger RNA/mRNA) 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.
    
    • The mRNA vaccine is a new approach to protecting against viral infection.
    • Unlike traditional vaccines, which work by training the body to recognise and kill proteins produced by pathogens, mRNA tricks the patient's immune system to produce viral proteins itself.
    • The proteins are harmless, but sufficient to provoke a robust immune response.
  • Its phase 3 clinical trial began in July with 43,538 participants, 38,955 of whom had received a second dose by November. The case split between vaccinated individuals and those who received the placebo indicates a vaccine efficacy rate above 90%, at 7 days after the second dose.
  • It means that protection is achieved 28 days after the initiation of the vaccination, which consists of a 2-dose schedule.
  • Pfizer has become the first firm to release promising late-stage trial data of a potential vaccine for Covid-19, even though the announcement does not have scientifically conclusive evidence on the safety and efficacy of the vaccine candidate.
  • However, the analysis of the vaccine candidate by an external independent Data Monitoring Committee (DMC) has not reported any serious safety concerns.
  • The announcement comes days before the company plans to submit safety and efficacy data from the trial to the American regulator, the United States Food and Drug Administration (USFDA) seeking emergency use authorisation.
• Vaccines Worldwide:
  
  • As of mid-October 2020, the World Health Organization (WHO) has identified 42 candidate vaccines at the stage of clinical trials, up from 11 in mid-June.
  • Ten of them were at the most advanced phase 3 stage, in which a vaccine's effectiveness is tested on a large scale, generally tens of thousands of people across several continents.
  • The USA biotech firm Moderna, several state-run Chinese labs, and a European project led by the University of Oxford and AstraZeneca are also closing in on potentially viable vaccines.
  • Two Russian Covid-19 vaccines have been registered for use even before clinical trials were completed, but have not been widely accepted outside of Russia.

India’s Progress

• India is preparing to administer a vaccine against Covid-19 to its population early in 2021 and for that, it is working with neighbouring countries on possible collaborative clinical trials of vaccine candidates in the future.
• A specialist team of scientists and researchers from the Indian Council of Medical Research (ICMR) and the Department of Biotechnology (DBT) under the Union Ministry of Science and Technology, has imparted training to doctors and regulators in Sri Lanka, Myanmar, Bangladesh, Bhutan, Nepal, and Afghanistan.
• The Indian team has focused its training on conducting crucial phase II and III human clinical trials of the potential vaccine candidate along lines of India’s regulatory mechanism.
  
  • In phases II/III, reactogenicity (ability to produce common, adverse reactions), immunogenicity (ability to provoke an immune response), and safety of the vaccine candidate are assessed in a larger population.
• The current aim is to facilitate a future collaborative clinical trial but in future, it will allow India to explore the option of buying the potential Covid-19 vaccine from these neighbouring countries.
• Indigenously Developed Vaccines:
  
  • ZyCoV-D: Designed and developed by Zydus (a pharmaceutical company) with support from the DBT.
  • Covaxin: Developed by Bharat Biotech in collaboration with the ICMR.
• Assistance in Global Trails:
  
  • Covishield: Name given to an Oxford-AstraZeneca Covid-19 vaccine candidate which is technically referred to as AZD1222 or ChAdOx 1 nCoV-19.
  • Sputnik V: The first vaccine to be officially registered and has been developed by Moscow’s Gamaleya Institute in collaboration with the Russia’s defence ministry.

Source: IE