BHUBANESWAR: Even as the vaccination drive has picked up pace and Covaxin has shown high efficacy rate, the fate of participants of the Phase-I trials of the Indian made vaccine is uncertain a year since they received the first jab.
Around 25 volunteers of the Phase-I human trial of Covaxin in the State are completing one year this month. But neither the vaccine manufacturer Bharat Biotech nor ICMR has come out with a course of action for them - if they need a booster dose now or they are deemed to be protected for a longer period.
These questions have gained currency after Pfizer made it public that people need a booster dose within 12 months of getting fully vaccinated and a likely scenario is that there will be an annual revaccination though variants will play a key role.
A total of 375 volunteers, including 25 from Odisha had received both the doses across the country. The trial was conducted at the IMS and SUM Hospital, here between July 27 and August 15, last year. Source said while the gap between the two doses during the first phase trial was 14 days, it was one month during the second phase human trial conducted in September-October. The gap was 28 days during the third phase trial and emergency use.
Though the volunteers participating in the Phase II trial were administered a booster dose five months after the second dose, there has been no clear information or instruction for those who are completing one year of vaccination.
Vaccine-induced neutralising antibody were observed with two divergent SARS-CoV-2 strains during the first phase and the percentage of all the side-effects combined was only 15 per cent in vaccine recipients.
Principal Investigator of Covaxin in Bhubaneswar Dr E Venkata Rao said the Phase 1 study had generated excellent safety data without any reactogenicity. “The volunteers were followed properly for 184 days. The vaccine manufacturer must be thinking of the next course of action, but there has been no communication to us,” he said.
Health experts said usually the vaccines and drugs introduced earlier had a life span of five to 10 years and even more than that as those were being allowed for public use after thorough study and trials. “Since the Covid-19 pandemic was a global concern, some vaccine candidates were approved for emergency use. The antibodies against spike protein and neutralising antibodies need to be studied in a gap of six months and a year. The manufacturer has to come out clear on the impact of the vaccine and whether any booster dose is required,” said former ICMR consultant Dr Tribhuban Mohan Mohapatra.