In March this year Antony Fauci, Director of the US National Institute of Allergy and Infectious Diseases in his statement to the U.S Senate expressed inability of the system to develop a vaccine for the next 1 to 1.5 years.
ICMR’s announcement on Covaxin launch has put the spotlight on COVID-19 vaccine development once again! : The announcement made by ICMR to launch Covid-19 vaccine by August 15 has led to a discussion about the time frame and various phases of the development of a vaccine. The process of developing a vaccine is not only a drawn out process which could take up to decades but also riddled with uncertainties and adverse outcomes.
According to an IE report, the vaccine for HIV which has been in the making for more than 3 decades is still in its third phase of clinical trials. Vaccines which are considered to have been developed substantially faster have also taken years. For instance the vaccine used for mumps which received the final approval after 4 years of clinical trials in the 1960s is considered to be one of the fastest developed vaccines in the world.
In March this year Antony Fauci, Director of the US National Institute of Allergy and Infectious Diseases in his statement to the U.S Senate expressed inability of the system to develop a vaccine for the next 1 to 1.5 years. He also added that even the timeframe of 1.5 years can be managed only if emergency approvals and authorisations are provided by the regulators. There are various stages involved in the development of a vaccine starting from Research and Development to its final delivery and large scale use on populations.
Stage 1 R&D
The process which takes anything between 2 to 4 years has been very quick in the case of Coronavirus. The reason for quick breakthrough in this stage was the fact that the Chinese government had shared the genetic sequence of the virus in January itself when the virus was within the confines of mainland China only. Also most vaccine candidates are not based on the protein of the vitus but its genetic sequence.
Stage 2: Pre Clinical
After the conclusion of the Research and Development, the vaccine is tested on animals and plants to analyse their efficacy and functioning. The scientists check whether the vaccine is inducing an immune response in the animal or plant body. If the answer is negative then the development turns back to stage 1 again which elongates the process.
Stage 3: Clinical trials
This is the most critical and significant stage in the development of vaccines as its efficacy is tested on humans. Out of the large number of candidates who succeed in reaching stage 2 fail to enter stage 3. This stage alone has the potential to take up to 90 months or close to over 7 years. This stage has 3 sub-stages or phases involved.
a)Phase 1: The vaccine is administered to a small group of people and they are tested to check whether antibodies have developed inside their bodies or not. This can take upto 3 months.
b)Phase 2: The number of people who are given the vaccine is enlarged to several hundreds and it may take upto 6-8 months on an average. The subjects are analysed to ascertain whether they develop the immune response against the disease. The ability of the vaccine to produce common and adverse reactions among the subjects called reactogenicity is also analysed. This stage has been shortened in the case of Coronavirus as several candidates which were in phase 2 some days back have now reached clinical trials phase 3.
c) Phase 3: Thousands of people are administered the vaccine and an attempt is made to see how the vaccine works in larger populations. This can again take another 6-8 months.
Stage 4:Regulatory review
After having succeeded in various stages and phases of human trials, the vaccine candidate seeks regulatory backing before embarking on the manufacturing of the vaccine. It usually takes a long time but in public emergencies like these, the time frame could be shortened.
Stage 5 : Manufacturing and Quality Control
This stage needs well oiled infrastructure of the vaccine producing company and financial resources to begin the process of manufacturing of the vaccine on a large scale.