the staff of the Ridgewood blog
New Brunswick NJ, according to Johns Hopkins Center for Health Security , Johnson & Johnson (J&J) published (preprint) preliminary findings from the Phase 1/2a clinical trials for its candidate SARS-CoV-2 vaccine (Ad26.COV.S). The studies included nearly 800 participants, who were split into 3 cohorts for the randomized, double-blinded, placebo-controlled study. The first 2 cohorts were made up of 402 healthy adults aged 18-55 years, and the third cohort included 394 healthy adults over the age of 65. The vaccine was given as a single dose or 2 doses administered 56 days apart. The vaccine was generally well tolerated, and the researchers reported 2 serious adverse events. One of the serious adverse events was determined to be unrelated to the vaccine, and the other was a fever that resolved within 12 hours.
Neutralizing antibody activity was observed in 98% of participants aged 18-55 years, and 99% of participants in those cohorts also demonstrated seroconversion following the vaccination. The younger adult cohorts also had strong T cell, antibody, and a Th1 cytokine response. Only 15 participants from the older cohort had immunogenicity data available, although the researchers reported that initial data are promising. Last week, J&J announced that it will commence Phase 3 clinical trials involving 60,000 participants across approximately 215 sites to test the single-dose vaccine formulation. The J&J candidate vaccine is the only vaccine in Phase 3 trials utilizing only 1 dose, which may expedite results of the trial.