Stages of vaccine development

Development of vaccines can be simplified into two broad stages:

1. Pre-clinical development is research carried out in lab assays and on animals.  It includes:

• • Identification (discovery) of relevant antigens (e.g. screening)
  • Evaluation of vaccine efficacy in test tubes and animals
• 2. Clinical development is when the vaccine is first tested in humans. 

• It covers four stages over several years, from initial clinical trials in humans (phase I) right through to introduction and beyond (phase IV). 
• Clinical development is built on rigorous ethical principles of informed consent from volunteers, with an emphasis on vaccine safety as well as efficacy.

Phases of clinical development

• Vaccines take several years to develop, and their development typically proceeds through three phases of clinical trials.
• In Phase 1, small groups of people receive the trial vaccine. 
• During Phase 2, the clinical study is expanded and the vaccine is given to people who have characteristics (such as age and physical health) similar to those for whom the new vaccine is intended.
• In Phase 3, the vaccine is given to several thousand people and tested for efficacy and safety. 
  • During this phase, participants either receive the vaccine or a placebo. 
  • The efficacy of the vaccine is determined by comparing the prevalence of infection in the group that was administered the vaccine with the one which received a placebo. 
  • The hypothesis that those in the vaccine group will be infected significantly less is thus tested.

Why in News?

Russia became the first country to officially register a corona virus vaccine and declare it ready for use, despite international skepticism.

News in Detail

• President Vladimir Putin emphasized that the vaccine underwent the necessary tests and has proven efficient, offering a lasting immunity from the coronavirus. 
• The vaccine will be marketed under the name ‘Sputnik V’ on foreign markets.
• Large-scale production of the vaccine is expected to start in September, and mass vaccination may begin as early as October.

Concerns

• The vaccine has been approved before the final stages of clinical trials -Phase 3 trials — which normally last for months and involve thousands of people— to test safety and efficacy are over.
• Scientists in Russia and abroad have expressed caution that the rush to start using the vaccine could backfire.

References:

1. https://economictimes.indiatimes.com/news/international/world-news/russia-registers-covid-19-vaccine-vladimir-putins-daughter-given-it/articleshow/77481415.cms
2. https://indianexpress.com/article/explained/human-challenge-trials-explained-6382949/
3. https://www.thehindu.com/sci-tech/health/when-will-a-covid-19-vaccine-be-ready/article31131211.ece/amp/http://www.euvaccine.eu/vaccines-diseases/vaccines/stages-development