The crossover will allow all trial participants to receive the vaccine while remaining blinded.
Today, Novavax has announced that they will begin crossover arms in two ongoing clinical trials assessing their vaccine for COVID-19, NVX-CoV2373. The biotechnology company has been developing next-generation vaccines for infection diseases, and has been one of the big contenders for developing a COVID-19 vaccine.
The initiation of crossover will allow the administration of active vaccines to all participants in the trials and has started in their phase 2b trial in South Africa, as well as its phase 3 trial in the United Kingdom.
The updated clinical trial protocols will offer all participants in the phase 3 trials in the UK and US the opportunity to receive an additional round of vaccination, and those who elect to do so will be administered an additional 2-dose regimen of either vaccine or placebo.
In the South African phase 2b trial, participants who initially received a vaccine will be given a booster shot of active vaccine, and those who had initially received a placebo will be given a dose of active vaccine.
All participants in the trials will remain blinded in order to preserve the ability to assess the vaccines efficacy in the each of the trials, and will be followed up to 2 years to monitor the safety and durability of protection the vaccine offers.
The company also announced that they plan on expanding the PREVENT-19 trial to include pediatric and adolescent populations.
"The crossover arms ensure that all participants have access to an active vaccine candidate while allowing Novavax to continue to monitor the safety and efficacy of our vaccine over the long term," Filip Dubovsky, Chief Medical Officer for Novavax said. "We are grateful to the volunteers who stepped forward to take part in our clinical trials, without whom we would be unable to develop, study and ultimately deliver what we hope will be a significant tool in the fight against COVID-19."