Bhubaneswar: The third phase human trial of Covaxin, the much-awaited indigenously developed Covid-19 vaccine, has begun at an institute here, a senior official said on Friday.
The vaccine was administered to two recruits on Thursday at the Preventive and Therapeutic Clinical Trial Unit (PTCTU) at the Institute of Medical Sciences and SUM Hospital, the only institute in Odisha chosen by the Indian Council for Medical Research (ICMR) for the human trial of the vaccine, E.Venkata Rao, the principal investigator in Covaxin human trial said.
The indigenous vaccine, which is being developed by Bharat Biotech and ICMR, has received approval of the Central Drugs Standard Control Organisation (CDSCO) for initiating the third phase trial. The trial is being conducted at 21 selected medical institutes across the country.
Rao said the vaccines first phase trial was aimed at measuring its safety, while phase two was meant to test its immunogenicity.
The third phase trial will check the efficacy of the vaccine, he said adding safety check (Phase 1) primarily looked at the safety aspect for human use without any significant side effect.
Immunogenicity check (Phase 2) measured the antibody level in the human blood and checked whether it was sufficient to protect the person from the infection, he said.
Phase three will evaluate if the vaccine was actually able to prevent development of the disease among the recipients of the vaccine, he said.
In fact phase three of the trial is crucial and tedious as we have to wait till the development of the disease which is dependent on the frequency of the disease in the population. So we need to recruit a large number of subjects and more than 25,000 volunteers were being recruited for the trial across the country, he said.
In phase three two doses will be administered to each volunteer 28 days apart. The follow up period will extend to 12 months to look at its long term and side effects, Rao, who is a professor in the department of community medicine at IMS and SUM Hospital, said.
Covaxin, he said, is an inactivated whole cell virion without the ability to produce the disease but helps in developing antibodies against the infection.
A virion is an entire virus particle consisting of an outer protein shell and an inner core of nucleic acid. The core confers ingectivity and the outer shell provides specificity to the virus.
These are time-tested vaccines while the others being developed were mRNA vaccines, new to human population, which send a signal into the human cell for the production of antibodies against the disease.
While recruiting volunteers for the phase three trial, the restriction of being a healthy volunteer was not mandatory. Anyone with diabetes or hypertension or with any other disease could also participate in the trial provided the disease was under control in them with medication, he said. Volunteers desirous of participating in the trial can register on-line or send a message through WhatsApp with their name, age, gender and the place of residence to 7849021450, he added.