The Central Drugs and Standards Control Organization (CDSCO), India’s top drug regulator has declared that it will only approve COVID-19 vaccines that meet their criteria such as the ability to show clinical outcomes by at least 50% during human testing. This also means that India can regulate the COVID vaccines given in the country to those who are diagnosed with the disease by 50% or higher, according to the experts. The CDSCO has also said that it needs adequate data informing the potential risk of vaccine-associated Enhanced Respiratory Disease (ERD) to widely deploy it in the country.
The regulator released a comprehensive set of guidelines for COVID-19 vaccines on Monday, emphasizing that the statistical range of efficacy cannot be lower than 30%. The guidelines of CDSCO are similar to those released by the World Health Organization (WHO) and the US Food and Drug Administration (US FDA), according to the experts who are closely following all COVID-19 vaccine updates. CDSCO stated, “To ensure that a widely deployed Covid-19 vaccine is effective, the primary efficacy end point estimate for a placebo-controlled efficacy trial should be at least 50 percent, and the statistical success criterion should be that the lower bound of the appropriately alpha-adjusted confidence interval around the primary efficacy endpoint point estimate is (greater than) 30 percent.” Explaining this, vaccine scientist and Christian Medical College, Vellore professor, Dr. Gagandeep Kang said, “What this essentially translates to is that the trial size has to be sufficient so that if the investigators get exactly 50 percent efficacy, we should have confidence that it will not be less than 30 percent.”
Probable vaccines around the world
Several vaccines are in the process of development around the world. Early tests of the AstraZeneca-Oxford University candidate vaccine showed that some animals contracted the infection even after getting vaccinated but it did not contract a lung infection or other severe manifestations of the disease. The vaccine is currently being tested in phase 3 clinical trials in several countries including India, in the Pune-based Serum Institute. The Hyderabad-based Bharat Biotech Limited is also working on a vaccine candidate, Covaxin and said that the animals vaccinated with this showed no presence of the virus.
Studies to continue over the vaccine
The guidelines also say that studies over the vaccine for safety assessment, usage during pregnancy, etc. will continue to get the best results. Dr. Balram Bhargava, ICMR, Director-General, said on Tuesday, “There are three things for a vaccine–(i) the safety, (ii) immunogenicity, and (iii) the efficacy. Even, WHO says that if we can get more than 50 percent efficacy that is an accepted vaccine. For respiratory viruses, we never get 100 percent efficacy. We are aiming for 100 per cent efficacy but may get 50-100 percent.” The guideline also maintains “If the trial fails to meet the predefined criteria for superiority and/or non-inferiority with respect to any of the antigenic components, the possible reasons for the result and the clinical implications of it should be carefully considered before proceeding with clinical development or licensure.”