Novavax's two-dose COVID-19 vaccine showed 90% overall vaccine efficacy (VE), 100% protection against moderate and severe illness, and 93% VE against variants of concern and of interest in a phase 3 US clinical trial in adults, according to a company news release today.
Maryland-based Novavax plans to file for regulatory authorization for adults within the next few months, the release said. While authorization wouldn't likely have much effect on the already robust US vaccine supply, it could provide a badly needed boost to the international vaccine rollout. Another plus is that it doesn't require ultra-cold temperatures for shipping and storage.
The Coalition for Epidemic Preparedness Innovations (CEPI), a global group of government and funding groups, said on Twitter today that 1.1 billion doses of the Novavax vaccine are slated for COVAX, an initiative focused on providing equitable access to COVID-19 vaccines globally, with the remaining needed doses slated to be supplied through the Serum Institute of India.
91% efficacy in high-risk groups
The trial of NVX-CoV2373, a recombinant nanoparticle protein-based coronavirus vaccine, enrolled 29,960 participants 18 and older at 119 locations in the United States and Mexico beginning in August 2020. Seventy-seven people later tested positive for COVID-19, 63 in the placebo group and 14 among vaccinees. While 10 moderate and 4 severe coronavirus cases occurred in the placebo group, all cases in the vaccine group were mild.
In a group of particular interest—those older than 65 years and younger people with certain underlying conditions or who work in high-risk occupations—the Novavax vaccine had 91.0% VE (62 cases in the placebo group vs 14 in the vaccine group).
Genomic sequence data available for 54 of the 77 COVID-19 cases showed 93.2% efficacy against variants of concern or interest and 100% efficacy against less transmissible strains. Of cases caused by variants of concern, 38 occurred in the placebo group and 6 among vaccinees.
The release noted that the Alpha (B117) coronavirus variant was the dominant strain in the United States at the time of study end point accruals, Jan 25 to Apr 30, 2021, and that cases of other variants of concern and interest were also climbing.
According to the Centers for Disease Control and Prevention, variants of concern are those with evidence of increased transmissibility, more severe illness, significant reduction in neutralizing antibody protection from infection or vaccination, lower effectiveness of therapies or vaccines, or COVID-19 test evasion. Variants of interest are those with genetic markers linked to changes in receptor binding, reduced antibody neutralization, or a predicted increase in spread or severity.
The vaccine was well tolerated in general, according to the release, with few serious and adverse events balanced between the two study groups. No one adverse event occurred in over 1% of participants. The most common local symptom in the 7 days after each dose was mild or moderate injection-site pain, while the most common systemic symptoms included fatigue, headache, and muscle pain, all of which resolved within 2 days.
Trial involving teens in the works
The company recently completed enrollment of 2,248 participants aged 12 to 17 years in the ongoing trial. The Novavax vaccine was recently shown in a UK phase 3 trial to have 96.4% VE against the original SARS-CoV-2 strain, 86.3% against the Alpha variant, and 89.7% overall.
It is also being tested in a phase 2b trial in South Africa, which found 55% efficacy overall in HIV-negative participants and 48.6% against the Beta (B1351) variant, and in a phase 1/2 study in the United States and Australia.
"Novavax continues to work with a sense of urgency to complete our regulatory submissions and deliver this vaccine, built on a well understood and proven platform, to a world that is still in great need of vaccines," Novavax President and Chief Executive Officer Stanley Erck said in the release.
The company intends to ramp up manufacturing to 100 million doses per month by the end of September and up to 150 million by the end of the year, the release said.
If given emergency use authorization by the US Food and Drug Administration, the vaccine would join three other COVID-19 vaccines already available in the United States: Pfizer/BioNTech (overall phase 3 VE after two doses in adults, 95.0%), Moderna (94.1%), and Johnson & Johnson (72% as a one-dose vaccine).