Novavax Vaccine Offers 89% Effectiveness Against COVID-19 in UK, But Less Potent in South Africa | Science

By Meredith Wadman, Jon CohenJan. 28, 2021 at 6:50 p.m.

ScienceCOVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.

Small biotech company Novavax, once seen as a dark horse in the COVID-19 vaccine race, today announced its candidate has high efficacy – 89.3% – in a pivotal UK trial where a New highly transmissible variant of the pandemic coronavirus accounted for more than half of the cases among those participating in the trial.

“These are spectacular results,” said Clive Dix, chairman of the UK Vaccine Taskforce, of the results of the trial, which recruited more than 15,000 people. “It is an incredible achievement that will ensure that we can protect individuals in the UK and the rest of the world from this virus.”

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But interim results from a separate Novavax trial in South Africa, in which a different and disturbing variant of SARS-CoV-2 accounted for most infections, were sobering. Among 4160 participants who were not living with HIV, the effectiveness was 60.1%. It fell to 49.4% when 240 other HIV-infected participants were included.

The South African coronavirus variant, named B.1.351 (and sometimes referred to as 501Y.V2), has three mutations in an important region of the virus spike protein. Recent test-tube studies have suggested that these mutations could allow the strain to escape the antibodies elicited by the vaccines. But today’s results are the first evidence from humans that this is the case.

“Now we know that there is some loss of vaccine efficacy, up to about 50-60%, ”says immunologist John Moore of Weill Cornell Medical College. “But it’s NOT zero. And a year ago, we would have settled for a vaccine that is 50% -60% effective.

Still, the South African essay has global implications. “The South African variant is a problem and reducing its global spread is a priority, ”says Moore. “The more it enters the United States, the more likely it is to develop.” As if to emphasize this point, today the South African variant has been identified for the first time in the United States. It was found in two people in South Carolina with no travel history, indicating that it may already be spreading in the community.

The Novavax vaccine uses technology that is distinct from other COVID-19 vaccines already authorized. It harnesses insect cells to make full copies of the spike protein that coats the surface of SARS-COV-2 and allows it to invade host cells. This is the first protein-based COVID-19 vaccine to present the results of a pivotal clinical trial. Like the COVID-19 vaccines authorized to date, it requires two doses. Another company, Janssen, is expected to announce results from a single-dose COVID-19 vaccine tomorrow.

Overall, vaccine experts praised the results of the two Novavax trials. Novavax has achieved “a remarkable achievement. We need as many effective vaccines as possible, ”says Luciana Borio, a vaccine expert who is vice president of In-Q-Tel, a technology investment company that invests in biosafety and other health technologies. national security.

Andrew Ward, a structural biologist at Scripps Research who co-authored the core article describing the structure of the Novavax vaccine, noted that compared to some other vaccines, “the cold chain requirements are much less stringent” for this vaccine, which only requires refrigeration at 2 to 8 degrees Celsius. “This is also great news for global immunization efforts, especially in the Third World and remote areas.”

Novavax this month launched an application for regulatory approval of its vaccine, called NVX-CoV2373, in the UK. He said that, including production at the Serum Institute of India, he could manufacture 2 billion doses of the vaccine this year. US approval will depend on the results of a recently launched 30,000-person trial in the United States and Mexico. This trial had more than 16,000 participants in its first 30 days.

Although the efficacy in South Africa is well below the 95% seen with the widely licensed mRNA vaccines from Moderna and Pfizer / BioNTech, South African scientists have found some good news, as the Novavax vaccine still has a degree of effectiveness against the variant. “Although there is certainly an impact [on how much protection it confers], it might not be as bad as we all thought, ”says Lynn Morris, who heads the South African National Institute of Communicable Diseases.

For the interim analysis of the trial in South Africa, in which 44 infections were recorded from last September to mid-January, 15 infections occurred among vaccinated participants and 29 infections among placebo recipients. Among the viruses sequenced, 25 out of 27, or 92.6%, showed an infection with the new variant B.1.351.

Novavax says it is working on the development of a bivalent vaccine that would attack both the South African variant and other sources of concern. Shabir Madhi, the dean of the faculty of medicine at the University of the Witwatersrand and the lead investigator in the South African trial, told reporters today that the work “may well come to fruition” within months.

South Africa has seen an explosion of cases since November. The new data suggests that this may be due in part to people who had COVID-19 earlier in the pandemic, recovered, and then were infected again with the new variant. This suggests that the variant may terminate natural immunity, just as it did to some extent with the Novavax vaccine.

In the placebo group of the study, 30% had been infected with SARS-CoV-2 before the study; these participants had the same COVID-19 rates during the trial as those who had never been infected before. Madhi called these figures “really worrying”.

“We would have expected that a large percentage of the population would have developed immunity from this first exposure,” he told reporters. “Unfortunately, past infection with earlier variants of the virus in South Africa does not protect against COVID-19 disease. It remains to be seen whether they have any value in terms of protection against serious illness or death. “

The British and South African studies were not large enough to assess the impact of the vaccine on serious illnesses. However, all COVID-19 vaccine trials to date – whether they are 50% or 95% effective against mild illness – have been at least 95% effective against severe illness.

Larger studies on the Novavax vaccine, like the one currently underway in the United States, could reveal its impact on serious illnesses, Madhi says. “In our experience with our respiratory vaccines, these vaccines generally work better against serious illnesses.”

So far, South Africa has not used any COVID-19 vaccine. The country yesterday approved the emergency use of a COVID-19 vaccine manufactured by AstraZeneca-Oxford. He plans to receive his first 1.5 million doses on Monday to start immunizing healthcare workers.

Glenda Gray, president and CEO of the South African Council for Medical Research, warns that the impact of B.1.135 on the Novavax vaccine could be a harbinger for other vaccines. “As newer variants start to circulate, we may see a decrease in vaccine efficacy in other vaccines currently being deployed globally,” she said.

Said Madhi: “SARS-CoV-2 taught us… to be humble and never question [the abilities of] the virus.”