Covishield COVID-19 vaccine maker Serum Institute of India's (SII) Founder Cyrus S Poonawalla was quoted by PTI as saying, "After six months, the antibodies go down and that's why I've taken the third dose." The billionaire added, "We've given the third dose to 7,000-8,000 SII employees." He further urged the people to take a third booster dose after six months.