Corona Vaccine Update: The Central Drugs Standard Control Organisation (CDSCO) has said that a COVID-19 vaccine candidate should show at least 50 per cent efficacy during phase III of clinical trials for it to be widely deployed. However, adequate data informing about the potential risk of vaccine-associated Enhanced Respiratory Disease (ERD) will need to be generated, the Central Drugs Standard Control Organisation (CDSCO) said in its draft ‘Regulatory Guidelines for Development of Vaccines with Special Consideration for COVID-19 Vaccine’.Also Read - Odisha: Bhubaneshwar Claims to be Fully Vaccinated Against COVID-19

“To ensure that a widely deployed COVID-19 vaccine is effective, the primary efficacy endpoint point estimate for a placebo-controlled efficacy trial should be at least 50 per cent…,” the guidelines said. Also Read - Maharashtra Lockdown: Section 144 Imposed in Mumbai, BMC Says Night Curfew to Continue Till 5 AM Daily | Full List of Guidelines Here

Speaking at a press conference on Tuesday, Dr Balram Bhargava, director general, Indian Council of Medical Research, said all vaccines for respiratory viruses are not 100 per cent effective. Also Read - Breaking: UAE Eases Restrictions For Indians, to Lift Ban on Transit Flights From Aug 5 | Details Here

“There are three things for a vaccine — first the safety, second the immunogenicity and third the efficacy. The WHO says that if we can get more than 50 per cent efficacy that is an accepted vaccine. For respiratory viruses, we never get 100 per cent efficacy. We are aiming for 100 per cent efficacy but may get 50-100 per cent.”

According to the CDSCO guidelines, as it is possible that a COVID-19 vaccine “might be much more effective in preventing moderate to severe versus mild COVID-19”, consideration should be given for powering efficacy trials for formal hypothesis testing on a severe COVID-19 endpoint.

Regardless, moderate to severe COVID-19 should be evaluated as a secondary endpoint (with or without formal hypothesis testing) if not evaluated as a primary endpoint, the guidelines said.

Establishing vaccine safety and efficacy in SARS-CoV-2 +ve  individuals is critical, they added.