Healthcare COVID-19 vaccine race: Johnson & Johnson says phase-3 trials underway Updated : September 24, 2020 06:37 PM IST J&J's COVID-19 vaccine candidate is based on the single shot technique. The Phase- 3 clinical trials involves 60,000 volunteers, who are being recruited globally. Subscribe to Moneycontrol PRO at just Rs.33/- per month for the first year. Use code SUPERPRO. Limited period offer. Available on Web and Android.