ABSTRACT
Clinical trials often depend on participants receiving study product to meet objectives of the protocol. Vitally important are considerations for how sites receive and dispense study product during a study while ensuring appropriate handling, accountability and compliance. The process for provision of study product is detailed in Standard Operating Procedures (SOPs) which are adhered to by the research site throughout the trial. The COVID-19 pandemic unexpectedly affected the ability of study participants to receive study product. We report on the various methods implemented by trial sites to ensure timely provision of study product to participants during this unprecedented pandemic. In MTN-035, participants received 3 potential rectal microbicide formulations in randomized sequences to understand user preferences. Trial sites were permitted to revise dispensing methods to enable participants to continue to receive study product during COVID-19 restrictions. These actions mitigated disruption of study product administration and preserved the integrity of the trial. Out of the 78 participants expecting to receive study products on or after the onset of restrictions due to COVID-19, only four participants (5%) did not receive all three products. Adopting alternative methods to provide product to study participants in extraordinary circumstances was key to successful study completion and maintaining study integrity.
ABSTRACT
Background: While Coronavirus disease 2019 (Covid-19) vaccines are highly effective, breakthrough infections are occurring. Booster vaccinations have recently received emergency use authorization (EUA) for certain populations but are restricted to homologous mRNA vaccines. We evaluated homologous and heterologous booster vaccination in persons who had received an EUA Covid-19 vaccine regimen. Methods: In this phase 1/2 open-label clinical trial conducted at ten U.S. sites, adults who received one of three EUA Covid-19 vaccines at least 12 weeks prior to enrollment and had no reported history of SARS-CoV-2 infection received a booster injection with one of three vaccines (Moderna mRNA-1273 100-mcg, Janssen Ad26.COV2.S 5x1010 virus particles, or Pfizer-BioNTech BNT162b2 30-mcg; nine combinations). The primary outcomes were safety, reactogenicity, and humoral immunogenicity on study days 15 and 29. Results: 458 individuals were enrolled: 154 received mRNA-1273, 150 received Ad26.CoV2.S, and 154 received BNT162b2 booster vaccines. Reactogenicity was similar to that reported for the primary series. Injection site pain, malaise, headache, and myalgia occurred in more than half the participants. Booster vaccines increased the neutralizing activity against a D614G pseudovirus (4.2-76-fold) and binding antibody titers (4.6-56-fold) for all combinations; homologous boost increased neutralizing antibody titers 4.2-20-fold whereas heterologous boost increased titers 6.2-76-fold. Day 15 neutralizing and binding antibody titers varied by 28.7-fold and 20.9-fold, respectively, across the nine prime-boost combinations. Conclusion: Homologous and heterologous booster vaccinations were well-tolerated and immunogenic in adults who completed a primary Covid-19 vaccine regimen at least 12 weeks earlier.