Public health experts have flagged the lambda variant of the coronavirus as one to keep an eye on as it circulates in South America and elsewhere while researchers try to determine how vaccines in the United States will measure up.
The lambda variant was first identified in Peru, where it has caused roughly 81% of COVID-19 cases sequenced there in the past two months. Since its discovery in December 2020, the variant has been identified in at least 29 countries, including Argentina, Mexico, and Germany, according to the World Health Organization. So far, no cases of the variant have been confirmed in the U.S.
The global health body designated the mutation as a “variant of interest,” but the WHO could upgrade the designation to “variant of concern” if researchers can prove that it spreads more easily or can evade the protection conferred by vaccines.
“Lambda carries a number of mutations with suspected phenotypic implications, such as a potential increased transmissibility or possible increased resistance to neutralizing antibodies,” the WHO said in its pandemic status report on June 15.
There have not been indications that lambda is more dangerous, but sequencing shows that the strain has a number of mutations that could increase transmissibility and make an outbreak much harder to suppress. Meanwhile, preliminary data from Chile suggest lambda could evade the Chinese-made CoronaVac vaccine, which already had a relatively low efficacy rate to start.
“We don’t have data for the lambda variant [versus U.S.-authorized vaccines], and we don’t have reasons to believe it will be different immunologically,” said Dr. Stuart Ray, a researcher and infectious disease expert at the Johns Hopkins University School of Medicine. “Preliminary data makes us worry a little, but the CoronaVac is different in composition to what vaccines we have here.”
Researchers have said with confidence that the vaccines authorized for use in the U.S. hold up against other variants, such as delta and alpha, and drastically reduce the risk of hospitalization and death due to COVID-19. A team of virologists at New York University uploaded preliminary findings last week that the Pfizer and Moderna vaccines are only modestly less effective against the lambda variant, adding that lambda “is not likely to cause a significant loss of protection against infection.” Researchers will have to continue investigating the variant to ensure that fully vaccinated adults in the U.S. are safe.
To date, more than 67% of U.S. adults have received at least one dose of vaccine, while more than 58% have completed the vaccination course. The outlook is dire for countries where vaccination rates are far lower due to the scarcity of shots. In Peru, for instance, roughly 14% of the population has received at least one shot, according to an analysis from Bloomberg.
Peru has been one of the worst-hit countries in Latin America. The extent of the damage caused by the pandemic in the small country of about 33 million people was not fully understood until early June, when the government updated mortality statistics to include deaths that were more than likely caused by the virus but can not be confirmed. The death toll due to COVID-19 ballooned from roughly 69,000 to more than 180,000 with the addition of suspected COVID-19-related deaths. Peru now has the highest number of deaths in the world in relation to the size of its population, with more than 595 deaths per 100,000 people.