A total of 800 adults aged 18 to 55 or aged 65 and up were randomized to various combinations of low-dose or high-dose vaccines or placebo, given 56 days apart.

Adverse events were common, with fatigue, headache, myalgia, and injection-site pain reported most often. At day 29 after the first dose, the seroconversion rate was 99% or more in the younger cohort across dosing groups. Older vaccine recipients had a 96% seroconversion rate. At 57 days after the first dose, antibody titers had increased further.

COVID-19: Single Dose of J&J Vaccine / Plasma / New Testing Requirement — https://www.jwatch.org/fw117413/2021/01/13/covid-19-single-dose-j-j-vaccine-plasma-new-testing

The J&J vaccine is in a multi-center, placebo-controlled, phase 1–2a trial. Here’s the link to the NEJM article https://www.nejm.org/doi/full/10.1056/NEJMoa2034201

From Stat Phase 3 results are coming soon.

There are two Phase 3 studies running. A 40,000-volunteer study of the one-dose vaccine, conducted in the U.S., is set to read out in the next two weeks. A second, equally big study is being conducted using the same vaccine given as two doses, each administered 57 days apart, in case the vaccine does not prove effective in a one-dose regimen or there are other advantages, such as the durability of the vaccine, to giving a second dose.

https://www.statnews.com/2021/01/13/data-fuel-debate-over-whether-jjs-one-dose-covid-vaccine-will-measure-up/ — Data fuel debate over whether J&J’s one-dose Covid vaccine will measure up

And from the Medscape article.

Unlike the Pfizer/BioNTech and Moderna messenger RNA vaccines, the Johnson & Johnson product is a recombinant, replication-incompetent adenovirus serotype 26 (Ad26) vector encoding a full-length and stabilized SARS-CoV-2 spike (S) protein.

The Next Likely COVID-19 Vaccine Has Its Advantages — https://www.medscape.com/viewarticle/944151?src=rss