The race against the virus that causes COVID-19 has taken a new turn: mutations are emerging rapidly, and the longer it takes to vaccinate people, the more likely it is that a variant that can escape current tests, treatments and vaccines will emerge.
Coronavirus is becoming more genetically diverse, and health officials say the high rate of new cases is the main reason. Each new infection gives the virus a chance to mutate while making copies of itself, threatening to undo the progress made so far to control the pandemic.
On Friday, the World Health Organization called for more efforts to detect new variants. And the US Centers for Disease Control and Prevention said a new version first identified in the UK could become dominant in the U.S. in March. Although it does not cause more serious illnesses, it will lead to more hospitalizations and deaths because it spreads much more easily, said the CDC when warning of “a new phase of exponential growth”.
“We need to do everything we can now … to get the transmission as low as possible,” said Dr. Michael Mina, an infectious disease specialist at Harvard University. “The best way to prevent the appearance of mutant strains is to delay transmission.”
So far, vaccines appear to remain effective, but there are signs that some of the new mutations may hinder testing for the virus and reduce the effectiveness of antibiotic drugs as a treatment.
“We are in a race against time” because the virus “can trip over a mutation” that makes it more dangerous, said Dr. Pardis Sabeti, an evolutionary biologist at the Broad Institute of MIT and Harvard.
Younger people may be less willing to wear masks, avoid crowds and take other measures to prevent infection because the current strain does not seem to make them very sick, but “in a mutational change, it can,” she warned. Sabeti documented a change in the Ebola virus during the 2014 outbreak that made it much worse.
It is normal for viruses to acquire small changes or mutations in their genetic alphabet as they reproduce. Those who help the virus to flourish give it a competitive advantage and therefore eliminate other versions.
In March 2020, just a few months after the coronavirus was discovered in China, a mutation called D614G emerged that may have made it more likely to spread. It soon became the dominant version in the world.
Now, after months of relative calm, “we have begun to see an impressive evolution” of the virus, biologist Trevor Bedford, of the Fred Hutchinson Cancer Research Center in Seattle wrote on Twitter Last week. “The fact that we’ve seen three variants of concern emerging since September suggests that there’s probably more to come.”
One was first identified in the UK and quickly became dominant in parts of England. It has been reported in at least 30 countries, including the United States.
Soon after, South Africa and Brazil reported new variants. On Tuesday, researchers at Cedars-Sinai Medical Center in Los Angeles said another new variant was found in a third of COVID-19 cases in that city and may have fueled its recent increase in cases.
The main mutation in the version identified in Britain also appeared in a different version “which is circulating in Ohio … at least as early as September,” said Dr. Dan Jones, a molecular pathologist at Ohio State University who announced that he found last week.
“The important finding here is that it is unlikely to be related to travel” and, instead, may reflect the virus by independently acquiring similar mutations as more infections occur, Jones said.
It also suggests that travel restrictions may be ineffective, said Mina. Because the United States has so many cases, “we can create our own variants that are just as bad or worse” as those in other countries, he said.
Some laboratory tests suggest that the variants identified in South Africa and Brazil may be less susceptible to antibody drugs or convalescent plasma, the antibody-rich blood of COVID-19 survivors. Both help people to fight the virus.
Government scientists are “actively studying” this possibility, said Dr. Janet Woodcock of the Food and Drug Administration last week. The government is encouraging the development of treatments with multiple antibodies, rather than drugs with a single antibody, to have more ways to attack the virus if one proves ineffective, she said.
Current vaccines induce immune responses broad enough to remain effective, say many scientists. A sufficient genetic change may eventually require adjustments to the vaccine formula, but “it will probably take years if we use the vaccine well, rather than months,” said Dr. Andrew Pavia of the University of Utah.
Health officials also fear that if the virus changes enough, people may receive COVID-19 a second time. Currently, reinfection is rare, but Brazil has already confirmed a case of someone with a new variant who fell ill with an earlier version several months earlier.
“We are seeing a lot of variants, viral diversity, because there are a lot of viruses out there,” and reducing new infections is the best way to contain them, said Dr. Adam Lauring, an infectious disease specialist at the University of Michigan at Ann Arbor.
Loyce Pace, who heads the nonprofit Global Health Council and is a member of President-elect Joe Biden’s COVID-19 advisory board, said the same precautions that scientists have been advising since the beginning “still work and are important”.
“We still want people to dress up,” she said. “We still need people to limit the congregation to people outside the home. We still need people to wash their hands and be really vigilant about these public health practices, especially as these variants emerge ”.