A healthcare professional administers the Novavax COVID-19 vaccine in the arm of a trial volunteer in Soweto, South Africa.
JOAO SILVA /The New York Times/ Redux
By Meredith Wadman, Jon Cohen
ScienceCOVID-19 reports are supported by the Pulitzer Center and the Heising-Simons Foundation.
Small biotechnology company Novavax, once considered an underdog in the COVID-19 vaccine race, announced today that its candidate was highly effective – 89.3% – in a key trial in the UK, where a new highly transmissible variant of the pandemic coronavirus responsible for more than half of the cases in people at the trial.
“These are spectacular results,” said Clive Dix, president of the UK Vaccine Taskforce, of the test results, which involved more than 15,000 people. “This 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 the interim results of a study with Novavax carried out separately in South Africa, in which a different and worrying variant of SARS-CoV-2 was responsible for most infections, were worrisome. Among 4,160 participants who were not living with HIV, the effectiveness was 60.1%. It dropped to 49.4% when an additional 240 HIV-infected participants were included.
The South African coronavirus variant, called B.1.351 (and sometimes referred to as 501Y.V2), has three mutations in an important region of the virus’s spike protein. Recent test tube studies have suggested that these mutations may allow the strain to escape antibodies produced by vaccines. But today’s results are the first evidence of human beings showing that they are.
“Now we know that there is some loss in vaccine effectiveness, below the 50% -60% level, ”says immunologist John Moore, of Weill Cornell Medical College. “But this is NOT zero. And a year ago, we would have settled for a 50% -60% effective vaccine. “
Still, the South African test has global implications. “The South Africa variant is a problem and reducing its global spread is a priority, ”said Moore. “The more often you enter the United States, the more likely it is to expand.” As if to emphasize, today the South Africa variant was first identified 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 produce complete copies of the spike protein that spreads over the surface of SARS-COV-2 and allows it to invade host cells. It is the first protein-based COVID-19 vaccine to report the results of an important clinical trial. Like the COVID-19 vaccines authorized to date, it requires two doses. Another company, Janssen, is due to announce the results of a one-dose COVID-19 vaccine tomorrow.
Overall, vaccine experts praised the results of both tests with Novavax. Novavax accomplished “a remarkable achievement. We need as many successful vaccines as possible, ”says Luciana Borio, a vaccine specialist who is vice president of In-Q-Tel, a technology investment company that invests in biosafety and other national security technologies.
Andrew Ward, structural biologist at Scripps Research and co-author of the foundational article describing the structure of the Novavax vaccine, noted that, compared to some other vaccines, “cold chain requirements are much less stringent” for this vaccine , which only requires cooling to 2 to 8 degrees Celsius. “This is also great news for global vaccine efforts, especially in the third world and in remote environments.”
Novavax initiated an application this month for regulatory approval for its vaccine, called NVX-CoV2373, in the United Kingdom. She said that, including production at the Serum Institute in India, it could produce 2 billion doses of the vaccine this year. US approval will depend on the results of a study of 30,000 people recently launched in the US and Mexico. This study accumulated more than 16,000 participants in its first 30 days.
Although the effectiveness in South Africa was much less than the 95% observed with widely authorized mRNA vaccines from Moderna and Pfizer / BioNTech, South African scientists found some good news, because the Novavax vaccine still has a certain degree of effectiveness against the variant. “While there is definitely an impact [on how much protection it confers], it may not be as bad as we all think it could be, ”says Lynn Morris, who heads the National Institute of Communicable Diseases in South Africa.
For the interim analysis of the South Africa study, in which 44 infections were recorded from last September to mid-January, 15 infections occurred among vaccinated participants and 29 infections among placebo recipients. Of the sequenced viruses, 25 of 27, or 92.6%, showed infection with the new variant B.1.351.
Novavax says he is working on the development of a bivalent vaccine that would attack both the South African variant and others that cause concern. Shabir Madhi, dean of the faculty of medicine at the University of Witwatersrand and the lead investigator for the trial in South Africa, told reporters today that this work “may very well be done” in a few months.
South Africa has had an explosion of cases since November. The new data suggests that this may be due in part to people who had COVID-19 early in the pandemic, recovered and were infected again with the new variant. This suggests that the variant may wipe out natural immunity, just as it did to some extent with the Novavax vaccine.
In the study’s placebo group, 30% had been infected with SARS-CoV-2 before the study; these participants had the same COVID-19 rate during the trial as those who had never been infected before. Madhi called these figures “really worrying”.
“We hoped that a large percentage of the population would have developed immunity from that first exposure,” he told reporters. “Unfortunately, previous infection with previous variants of the virus in South Africa does not protect against COVID-19 disease. Whether they have any value in terms of protection against serious illness or death remains to be seen. “
Studies in the United Kingdom and South Africa were not large enough to assess the vaccine’s impact on serious illnesses. However, all trials of the COVID-19 vaccine to date – have either 50% or 95% effectiveness against minor illnesses – have been at least 95% effective against serious illnesses.
Larger studies of the Novavax vaccine, such as the one currently underway in the United States, may reveal its impact on serious illnesses, says Madhi. “Based on experience with our respiratory vaccines, these vaccines generally work best against serious illnesses.”
So far, South Africa has not used a COVID-19 vaccine. Yesterday, the country approved the emergency use of a COVID-19 vaccine from AstraZeneca-Oxford. She plans to receive her first 1.5 million doses on Monday to start vaccinating health workers.
Glenda Gray, the president and CEO of the South African Medical Research Council, warns that the impact of B.1.135 on the Novavax vaccine may be a harbinger of other vaccines. “As the new variants begin to circulate, we can see a decrease in the vaccine’s effectiveness in other vaccines that are being launched globally,” she says.
Says Madhi: “SARS-CoV-2 taught us… to be humble and never question [the abilities of] the virus.”