By Denise Chow - NBC News
Scientists are focused on a handful of coronavirus mutations that could pose new public health challenges if circulated in massive numbers, they predict.
His focus: the tiny protein spikes that give the virus its characteristic corona shape and that coat the outside of the virus.
It's those proteins that researchers have targeted to create vaccines, using them to prime the body's immune system to produce antibodies to fight the virus.
But it is also where they have observed some mutations that have forced vaccine manufacturers to react.
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A variant that emerged in South Africa is highly relevant as mutations in spike proteins that can make antibodies less effective.
And while none of those changes appear to have resulted in a virus capable of evading current vaccines, it is an area of great interest to researchers.
"The spike protein is like the key that unlocks our cells,"
explained Simon Clarke, associate professor of cell microbiology at the University of Reading in England.
"If you have mutations in the spread protein, it could make the key work more effectively, or it could change the structure of the key slightly so that it can still access our cells, so that antibodies cannot bind and fight it. ".
An initial analysis by Moderna revealed that while its vaccine appears to be less effective against the South African variant, the antibodies remained above protective levels.
The Pfizer-BioNTech Labs vaccine is only slightly less effective against the South African strain, according to a study that has yet to be peer-reviewed.
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The coronavirus has likely undergone thousands of changes since it spread to humans.
Several variants, including one that was first reported in the UK and another that is believed to have arisen in Brazil, are already being tracked around the world.
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But scientists remain concerned about the emergence of other variants of the coronavirus, especially if one of them renders the vaccines useless.
"Mutations can make a virus more transmissible or make a virus less susceptible to some antibodies, so this is always a big concern," Clarke said.
So far, vaccines appear to protect against known variants, according to Dr. Bruce Y. Lee, professor of health policy and management at the City University of New York.
Even if a vaccine protects less against one strain, it is likely to be beneficial in preventing the most severe cases of COVID-19, which not only helps patients, but also minimizes the workload in hospitals.
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"Even if a flu vaccine is 30% effective, we recommend getting the vaccine," Lee agreed.
Members of the Tshwane Special Infectious Unit on COVID-19 transport a suspected infected patient on January 15, 2021 in Pretoria, South Africa.Alet Pretorius / Gallo Images via Getty Images
But that doesn't mean there are no risks yet, especially with the crucial role that the virus' spike protein plays.
Both the South African variant and the UK variant contain a spike protein mutation called N501Y, which is believed to make them more contagious.
The South African variant also carries a mutation known as E484K, which could make it less susceptible to antibodies produced by vaccines or accumulated from natural infection.
And because vaccines target the spike protein, there is concern that mutations in that part of the virus could affect how well vaccines work, according to Lee.
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"If you change the spike protein enough, the question is, 'How will the immune response change?'
The effectiveness of vaccines depends on our immune response to that spike protein, "he added.
Research continues, but the observed declines in vaccine efficacy have already led Moderna to begin adjusting its vaccine to make it more effective against emerging strains.
Although Moderna dosages appear to protect against known variants, the company's chief executive Stéphane Bancel reported last month that the updates are being developed "out of a precaution."
AstraZeneca and the University of Oxford, which jointly developed a vaccine that is licensed for use in the UK but not yet in the US, announced Wednesday that they intend to produce an improved version to protect against known variants. , which might be available in the fall.
And scientists hope that more variants will emerge as the virus evolves.
UK scientists reported on Tuesday that the E484K mutation in the South African variant has also been found in a small number of cases related to the UK strain in England.
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"The more a virus replicates, the more likely it is to make random changes
," Lee explained.
"Many of these changes will not make a difference, but from time to time, there will be a change that will give the virus an advantage, which will allow it to survive, replicate or infect people," he added.
The outlook adds urgency for countries to aggressively control the spread of the virus, limiting the opportunity for new, more problematic variants to circulate.
"What we do now can affect the course of the pandemic in the coming weeks," Lee warned.