“Efficacy of the Johnson & Johnson vaccine (AD26.COV2.S) for prevention of SARS-CoV-2 in Adult Participants currently being studied. Currently, efficacy is unknown – there is no recognized effective vaccine for the treatment of COVID-19. Estimated Study Completion Date: January 2, 2023”

Janssen Vaccines & Prevention B.V. (updated 26 March 2021). A Study of Ad26.COV2.S for the Prevention of SARS-CoV-2-Mediated COVID-19 in Adult Participants. Clinicaltrials.gov. Retrieved 2 April 2021. https://clinicaltrials.gov/ct2/show/NCT04505722.