Oct. 27 (UPI) -- Maryland-based biotech firm Novavax on Tuesday announced it's delayed the start of its Phase 3 testing of a potential COVID-19 in North America.
The late-stage testing of vaccine candidate NVX-CoV2373 is now expected to begin by the end of November, about a month later than expected.
Novavax said delays in scaling up its manufacturing process of the vaccine candidate are to blame for the delay in testing in the United States and Mexico. The trial will include up to 30,000 participants in both countries with proportional representation among populations most vulnerable to the virus.
The company has already entered Phase 3 of its clinical trial in Britain, with 5,500 people enrolled. The trial is expected be fully enrolled by the end of November, with results by early 2021.
Novavax said these results should serve as the basis for government approval of the vaccine.
Novavax published the results of its early-stage testing in September, saying NVX-CoV2373 produced immune responses greater than that found in COVID-19 convalescent serum and induced T cell responses during a randomized, placebo-controlled, early-phase trial that started in May.
Novavax said the initial trial of 131 healthy adults in Australia showed NVX-CoV2373 was well-tolerated and adverse side effects were generally mild.
All subjects in a group that received smaller amounts of the vaccine developed neutralizing antibodies against the novel coronavirus that causes COVID-19 after two doses administered a month apart, the study found.
NVX-CoV2373 is one of several "protein subunit" COVID-19 vaccines in development around the world. These types of vaccines don't contain any live pathogens and instead use smaller pieces, or subunits, of the virus to induce a protective immune response. They are generally considered safer than "whole pathogen" vaccines and can be manufactured more quickly, but they usually elicit weaker responses and may require an "adjuvant" to boost their effectiveness.
Novavax said it plans to deliver 100 million doses of a vaccine to the United States as part of its participation in the Trump administration's Operation Warp Speed.