Novavax COVID-19 vaccine demonstrates 96 percent efficacy against original strain, 55 percent against South African strain

Results are in from the latest trials of NVX-CoV2373, Novavax, Inc.’s COVID-19 vaccine candidate, and while it only provided 55.4 percent efficacy in a region beset by the South African variant, it displayed 96.4 percent efficacy against the original strain and 86.3 percent against the United Kingdom variant in UK testing.

These figures focused on mild, moderate to severe cases in Phase 3 (UK) and 2b (South Africa) trials. In South Africa, those numbers came from participants that were HIV-negative. The good news, in both cases, is that efficacy against severe disease — including hospitalization and death — was 100 percent.

“We are very encouraged by the data showing that NVX-CoV2373 not only provided complete protection against the most severe forms of disease but also dramatically reduced mild and moderate disease across both trials,” Stanley Erck, president and CEO of Novavax, said. “Importantly, both studies confirmed efficacy against the variant strains. Today marks one year since the WHO officially declared the COVID-19 pandemic, and with this data in hand, we are even more motivated to advance our vaccine as a potential weapon in the fight to end the suffering caused by COVID-19.”

The UK trial enrolled more than 15,000 participants between ages 18 and 84, while the South African trial enrolled approximately 2,665 healthy adults and 240 medically stable, HIV-positive adults. The UK results were so successful the company expects to utilize its data to serve as submissions for authorization to regulatory agencies worldwide.

In all cases, the vaccine also proved well-tolerated, with only low levels of severe, serious, and medically attended side effects. It is also capable of stable storage at refrigeration temperatures, giving it a major advantage over certain other COVID-19 vaccines, which require deep-freeze storage.