Coronavirus: Moderna says vaccine works against new Covid-19 variants
- Lab tests show shot produces comparable antibody protection against UK strain, but immunity may wane more quickly for South Africa variant
- Both strains thought to be more infectious and British officials said the variant discovered in UK may be deadlier
US biotechnology firm Moderna said its vaccine will protect against two known variants of the virus that causes Covid-19, but it plans to start human studies of a booster shot for a strain from South Africa that may cause immunity to wane more quickly.
In laboratory tests, Moderna’s vaccine produced antibody protection against the strain first identified in Britain, known as B.1.1.7, at levels comparable with older versions of the virus. But against the South Africa variant, known as B.1.351, the neutralising antibodies produced were six-fold lower, the company said in a statement.
Despite that decrease, Moderna’s vaccine should protect against either strain, according to the company. While the South Africa variant has not been seen in the US, the UK mutation, which British officials said last week may be deadlier than earlier forms of the disease, is spreading rapidly among Americans.
Both strains are thought to be more transmissible than the original version of the virus.
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“We expect that whatever immunity you get over time will wane, the question is will it wane faster if you have lower levels to begin with,” said Tal Zaks, Moderna’s chief medical officer, in an interview.
Moderna shares gained as much as 12.5 per cent in New York trading, the biggest intraday gain since December 1. Over the past 12 months, the company’s stock price has soared more than 500 per cent.
The results came from tests Moderna conducted with the National Institute of Allergy and Infectious Diseases. While the shot produced neutralising antibodies above levels that protect monkeys, the new studies will determine if that holds true with humans.
In the upcoming study, Moderna plans to give people who have already received two doses of its current vaccine a booster shot against the South African variant after six to twelve months. Researchers would then measure whether the booster led to higher levels of infection-thwarting antibodies.
Additionally, Moderna plans to test a booster shot of its existing vaccine in people, the company said in a statement. The exact timing and design of these trials has not yet been determined, Zaks said.
It is not clear yet how often people might need booster shots, he said. It is possible that annual booster shots could be needed, just as they are for influenza. But Zaks said it is also possible that a single booster shot could protect people for a long time, he said.
“We don’t know that yet,” he said. “Our job is to prepare for every eventuality that may occur.”
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On Monday, top US infectious-disease expert Anthony Fauci said he was concerned about the ability of vaccines to protect against new variants of the coronavirus and that drug makers may need to tweak their shots to address new mutations.
“There seems to be considerable more threat to vaccine efficacy, even though the cushion of efficacy is sound enough that the vaccines we’re using now will be good against both the mutant in South Africa as well as those in the UK,” Fauci said.