The ICMR chief, Dr Balram Bhargava, has said that no vaccine for respiratory diseases has a 100% efficacy and ones with 50-100% efficacy can be approved for use against the coronavirus, the Times of India has reported. He added that although maximum efficacy will be sought, but the WHO has said that a vaccine with 50% efficacy can be accepted. The comment came a day after Central Drugs and Standard Control Organisation issued a note for Covid-19 vaccine that suggested researchers may not necessarily look for the preventive capacity of a vaccine. and settle for one that protects a person from developing severe infection.