Pfizer vaccine appears effective against rapidly spreading coronavirus variants
Coronavirus variants that have ripped through the UK and South Africa in the past month are being heavily scrutinized in laboratories around the world as scientists try to get a hold on how much of a threat the mutated strains pose. One of the chief concerns is that new variants may be able to evade current vaccines, including the two developed by Pfizer/BioNTech and Moderna currently being rolled out in the US.
On Thursday, a Reuters report describiing a new study showed Pfizer’s vaccine can effectively neutralize the variants with a mutation known as N501Y, which arose in variants found in South Africa and the UK variant, known as B.1.1.7, independently. The study is yet to be peer-reviewed but can be found on preprint depository bioRxiv.
“It’s preliminary, but it definitely suggests that the vaccine will also work against these variants,” said Larisa Labzin, an immunologist at the University of Queensland.
Coronaviruses mutate constantly as they pass from human to human and, for the most part, don’t significantly alter the virus. A handful of mutations, though, including those in the B.1.1.7 strain, appears to allow the virus to spread more quickly. These changes occur in the virus’s spike, a critical protein that allows the virus to enter and hijack human cells.
When news of B.1.1.7 being more transmissible first broke, there was reason to be cautious. The new data was initially provided by Prime Minister Boris Johnson in a UK press conference on Dec. 19., it was too early to tell how the mutations may have changed the characteristics of the virus. Simply put, we needed more data.
Importantly, the new variant does not appear to be more deadly, as Johnson noted in his presser. “There is no evidence the variant causes more severe illness or higher mortality, but it does appear to be passed on significantly more easily,” he said. However, scientists were unsettled by the potential for the variant to evade our current vaccines.
They’ve taken antibodies from people who have been immunized with the vaccine and checked to see if those antibodies can still stop the new variants, with a critical change in their spike protein
But in the weeks since, the variant has appeared in numerous locations around the world, including the US and Australia, where it breached the hotel quarantine system and forced the city of Brisbane into an immediate three-day lockdown. The heightened concern has rippled across the globe and many nations have increased scrutiny at their borders or outright closed them to UK travelers.
To test the capability of current vaccines against the new variants, Pfizer used blood serum from 20 individuals who had received the vaccine. This serum contains antibodies to the vaccine and can be tested against viruses with different mutations in the lab. The interim results look good.
“So we’ve now tested 16 different mutations and none of them have really had any significant impact. That’s the good news,” Phil Dormitzer, a viral vaccine scientist with Pfizer, told Reuters.
“That doesn’t mean that the 17th won’t.”
It will be critical to test other aspects of the immune response, Labzin said, like how specialized white blood cells respond to an infection with the variant after vaccination. Other mutations in the variants will also be examined.
“There are more mutations in the spike protein than just the one they tested in this variant, but it’s definitely positive news,” she said.
If the variants were to mutate in such a way they begin to diminish the efficacy of current vaccines, we don’t have to go all the way back to the drawing board. That’s thanks to the “plug-n-play” nature of Pfizer and Moderna’s vaccines. These vaccines use mRNA and can potentially be “recoded” within a few months to combat new variants. However, while, this has never been trialled before.
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