Some Lab Work Hints Preamble, But will that feather the Reality? That is unclear.
As new variants of the coronavirus that causes COVID-19 emerge, a slew of new studies suggest that some may be able to evade immune responses triggered by a previous infection or by a vaccine. That worry has already prompted some vaccine makers to look for ways to tweak their shots to keep up with these troublesome newcomers.
Researchers had been concerned that mutations in a viral protein that helps the coronavirus break into cells could dampen the immune response against the virus. The new studies suggest that some viral variants may escape at least some of that immunity, which could put people who have been vaccinated or who have already recovered from a bout of COVID-19 at risk of getting infected.
Still, “we should urge caution, but not panic,” says Mark Slifka, a microbiologist and immunologist at Oregon Health & Science University in Portland. “The immune system has multiple backups” to cope with ever-changing viruses, he says.
What’s more, it should be straightforward — at least in principle — to update vaccines that rely on parts of the coronavirus’s genetic code to trigger an immune response (SN: 7/10/20). And while some virus mutations could put a dent in how well the vaccines work, currently authorized shots have a long way to fall before they might become ineffective, Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases and chief medical adviser to President Biden, said in a Jan. 21 news briefing.
COVID-19 vaccines developed by Pfizer and Moderna proved highly effective in clinical trial (SN: 12/18/20), with an efficacy of about 95 percent. The U.S. Food and Drug Administration recommends that COVID-19 vaccine candidates should have an efficacy of at least 50 percent for emergency use authorization (SN: 10/4/20).
Mix of mutations
Viruses mutate all the time, and the coronavirus that causes COVID-19 is no exception (SN: 5/26/20). While most changes have little to no effect on how the virus behaves when it infects a person, a few rare alterations can make some viral variants more dangerous to people, such as making a virus more transmissible or deadly.
Another danger can arise if a mutation helps the virus elude the body’s immune response. Protection from any virus comes, in part, in the form of immune proteins called antibodies, which latch on to proteins on the virus. The immune proteins can prevent the virus from getting into other cells or spur other immune cells into action. Mutations in viral proteins can weaken or prevent that binding, making the antibody response less effective.
Such problematic mutations are now appearing in a few versions of the coronavirus that researchers are tracking. A virus variant called B.1.1.7, first identified in the United Kingdom, appears to be more transmissible than its close relatives, giving it a potential evolutionary advantage (SN: 12/22/20). Researchers are also monitoring the spread of a variant in South Africa — dubbed 501Y.V2, and also known as B.1.351— that has some of the same mutations as B.1.1.7, as well as other changes. Another potentially concerning variant called P.1 has emerged in Manaus, Brazil — a region that was already hit hard by the pandemic in 2020 (SN: 9/24/20).
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