The crucial phase 3 trials for Covishield vaccine, which is expected to test the immunogenicity of the vaccine, has begun at JSS Academy of Higher Education and Research (JSSAHER) in Mysuru.
After the conclusion of the phase 2 trials during which no adverse effects were shown by any of the 25 healthy volunteers, the phase 3 trials envisaging inoculation of a total of 120 volunteers had begun.
Covishield is a vaccine candidate developed by Oxford University and multinational pharmaceutical company AstraZeneca. JSSAHER is one of the 18 centres carrying out the clinical trials on humans for the vaccine candidate produced by Serum Institute of India (SII).
Out of the estimated 1,400 volunteers from across the 18 centres participating in the clinical trials, 120 will be from JSSAHER. “About 80 out of the total 120 volunteers have been inoculated. The remaining 40 will be covered by the end of this week”, JSSAHER’s Pro Chancellor B. Suresh told The Hindu.
The phase 2 trials in Mysuru began around August 29 and none of the 25 volunteers showed any adverse effect during the 28-day trial period. While the phase 2 trials were aimed at checking the safety of the vaccine, the phase 3 trials will assess its immunogenicity. “We were not authorised to check if the volunteers had developed antibodies during the phase 2 trials”, Dr. Suresh said adding that the volunteers will be monitored during the 28-day-long phase 3 trials by the end of which they will be tested for presence or absence or antibodies against COVID-19.
By November-end or early December, the data from all the 18 centres including JSSAHER will be sent to SII, which in turn will forward the same to Indian Council for Medical Research (ICMR), Dr. Suresh said and referred to the Union Health Minister Harsh Vardhan’s statement that the first vaccine is likely to be available by early 2021 in the country.
However, even if there are positive indications about the presence of antibodies among the volunteers, Dr. Suresh said studies will have to be carried out further to check how long the anti-bodies last in the human bodies. “We will have to see if they (antibodies) will be sustained for a year or for a life-time or for four to five years. This will determine whether we need to keep giving repeated shots of the vaccine or whether it will be one-time vaccine”, he said.
The clinical trials were open to the public to participate and the healthy volunteers, who had come forward and registered themselves, were first subjected to exclusion criteria based on morbidities including diabetes and blood pressure, besides not having been exposed to COVID-19.
If the volunteers had already been exposed to COVID-19, antibodies will be present in the blood, which will give false results. So, the two tests the volunteers underwent included the RT-PCR test for COVID-19 and a test for presence of antibodies. The purpose of the trials is to see if the vaccination generates the type of antibodies that is required for assessment by the laboratories, he said.
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