Saturday, May 25, 2024

The city runs a coronavirus test clinic on Church Street in Harvard Square. (Photo: Marc Levy)

The first Massachusetts case of a Covid-19 variant tracked from South Africa is a resident of Cambridge, the Cambridge Public Health Department said Thursday.

The case, a woman in her 20s, tested positive for Covid-19 in January and was isolated in accordance with guidance from the Centers for Disease Control and Prevention, with no known contacts connected with her case, the Public Health Department said. Detection of the variant – known as B.1.351 – comes many weeks after a test because genome sequencing, which confirms the variant, takes more time to conduct.

There was no travel history connected with the woman’s case, health officials said.

According to the CDC, the variant is known to spread easily, like the “B.1.1.7” variant originally found in the United Kingdom that now has 29 known cases in Massachusetts. The evolution of variants of the coronavirus “is to be expected,” the Public Health Department said, but they are yet not considered to be widespread here.

The two approved vaccines for Covid-19, one made by Cambridge-based Moderna and the other by Pfizer and BioNTech, elicited somewhat less antibody protection against the mutations in the South African variant, with Moderna showing a weaker response than Pfizer, according to two research letters from the companies published Wednesday in the New England Journal of Medicine. Both letters said it’s not clear what that means in terms of the vaccines’ efficacy in preventing symptomatic Covid-19. The findings were based on laboratory tests.

Both vaccines demonstrated more than 90 percent efficacy against the original coronavirus in studies based on tens of thousands of people who got a vaccine or a placebo. The companies have also said research shows their vaccines are equally effective against the British variant of Covid-19.

“Detection of the B.1.351 COVID-19 variant is testament to the strength of our [state] communicable disease surveillance system,” said Claude A. Jacob, chief public health officer for the Cambridge. “It is also a reminder that this pandemic is far from over, and we all must continue to wear masks, social distance, and get vaccinated when it is our turn.”

Call for more sequencing

The United States is sequencing the genomes of less than 1 percent of Covid-19 samples to detect variants. In Massachusetts, about 0.69 percent of samples have been sequenced, according to the most recent CDC data. Other countries, especially Britain, sequence far greater proportions, and scientists have called for more sequencing here.

The state Public Health Laboratory now is sequencing 100 cases a week, double the number before Jan. 1, and the Cambridge-based Broad Institute of Harvard University and Massachusetts Institute of Technology, which is working with the state, expects to sequence 900 samples a week by March. The Cambridge case was detected by sequencing at the Broad, the state Department of Public Health said.

The state agency urged residents to improve the fit of masks by adjusting ear loops and nose wires and tucking the sides, and use multilayered masks or filters, as well as observe Covid-19 precautions such as social distancing, avoiding groups, staying home when ill and getting vaccinated.

This post was written from a press release.