India’s first domestically COVID-19 vaccine, Covaxin, has shown “robust immune responses” with barely any serious side effects, according to a research paper published by the Hyderabad-based firm.
COVAXIN is an indigenously developed coronavirus vaccine developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR).
According to the findings which have appeared on medRxiv, a preprint server, the vaccine induced robust binding and neutralising antibody responses which were comparable to those observed in the convalescent serum collected from patients who had recovered from COVID-19.
A double-blind randomized controlled phase 1 clinical trial was conducted to evaluate the safety and immunogenicity of BBV152 (manufactured by Bharat Biotech) is a whole-virion, inactivated SARS-CoV-2 vaccine, said the document titled "A Phase 1: Safety and Immunogenicity Trial of an Inactivated SARS-CoV-2 Vaccine BBV152".
"We report the interim findings from this phase 1 clinical trial of BBV152, a whole-virion inactivated SARS-CoV-2 vaccine. The vaccine was well tolerated in all dose groups with no vaccine-related serious adverse events. The most common adverse event was pain at the injection site, which resolved spontaneously. The overall incidence rate of local and systemic adverse events in this study was 10 per cent-20 per cent in all vaccine treated arms, which is noticeably lower than the rates for other SARS-CoV-2 vaccine platform candidates and comparable to the rates for other inactivated SARS-CoV-2 vaccine candidates," stated a pre-print document.
The document noted that one serious adverse event was reported and the participant was screened on July 25th and vaccinated on July 30th. Five days later, the participant reported fever and headache (initially reported as a solicited adverse event), and on August 8th was found to be positive for SARS-CoV-2 (by a nucleic acid test). The symptoms were initially mild in nature, which the onset of relapsing fever requiring admission to the hospital on August 15th.
"One serious adverse event was reported in the 6 µg with Algel group. The participant was screened on July 25th and vaccinated on July 30th. Five days later, the participant reported fever and headache (initially reported as a solicited adverse event), and on August 8th was found to be positive for SARS-CoV-2 (by a nucleic acid test). The symptoms were initially mild in nature, which the onset of relapsing fever requiring admission to the hospital on August 15th. The participant had stable vitals (except body temperature) during hospitalization and did not require supplemental oxygen. The participant was discharged on August 22nd following a negative nucleic acid result. The event was not causally associated with the vaccine. No other symptomatic SARS-CoV-2 infections were reported between day 0 and 75. However, follow-up of routine SARS-CoV-2 nucleic acid testing was not conducted on any scheduled or illness visit," the document said.
"Reactogenicity was absent in the majority of participants, with mild events. The majority of adverse events were mild and resolved. One serious adverse event was reported, which was found to be unrelated to vaccination.
"Vaccines were administered on a two-dose intramuscular accelerated schedule on day 0 (baseline) and day 14. The primary outcomes were reactogenicity and safety." The document said that BBV152 is stored between 2degC and 8degC, which is compatible with all national immunization program cold chain requirements, and further, efficacy trials are underway.
To ensure generalizability, this study was conducted with participants from diverse geographic locations and socioeconomic conditions, enrolling 375 participants across 11 hospitals, it noted.
"Despite the fact that enrollment occurred during a national lockdown, which led to several operational challenges, the overall participant retention rate was 97%. The sample size was intentionally large to enable the inference of meaningful conclusions regarding immunogenicity and safety," it read adding that BBV152 induced robust binding and neutralizing antibody responses that were similar to those induced by other SARS-CoV-2 inactivated vaccine candidates, it said.