One research study published in the journal Science estimated that 76 percent of the Manaus population already had been infected by the coronavirus. That should have put Manaus close to herd immunity. The new surge has raised fears that the P.1 variant has mutations that allow it to evade the human immune system. Evidence to support this hypothesis remains limited.
The Minnesota Department of Health said the case there involved “a Minnesota resident with recent travel history to Brazil,” and the variant was detected through genomic sequencing of random nasal swabs as part of a surveillance program.
The person, a resident of the Twin Cities metro area, reported feeling sick the first week of January and was tested Jan. 9. The health department said the person has been in isolation, and the department is continuing to investigate the case.
“This isn’t surprising. It’s a very difficult development, but at the same time not unexpected,” Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota and an adviser to President Biden’s coronavirus task force, said in an interview.
All viruses mutate, and there are countless variants in circulation. The Brazil variant is one of three that have drawn particular global attention. The other two were first identified in the United Kingdom and South Africa, and are known to virologists as B.1.1.7 and B1.351.
Although scientists know quite a bit about the U.K. variant, the Brazil variant “is probably the one causing the most concern among people watching this,” William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health, said Monday. “It is fair to say that P.1 is the object of very, very serious attention and concern among epidemiologists. We don’t know why it has been so successful in Manaus.”
The U.K. variant — already spreading in the United States — has become the dominant strain in southern England, and the Centers for Disease Control and Prevention has said it could become dominant in the United States by some point in March if it outcompetes other strains. Minnesota has detected eight cases involving the U.K. variant, officials said Monday.
The South Africa variant has not been identified in the United States.
“These cases illustrate why it is so important to limit travel during a pandemic as much as possible,” Minnesota state epidemiologist Ruth Lynfield said in a statement released by the health department.
There is some overlap in the mutations in the three variants, but they arose independently and, along with other variants under review, provide a vivid reminder that the coronavirus is not a static target for vaccines and the human immune system. Most scientists believe the vaccines will remain effective against the variants, a belief bolstered by research released Monday by Moderna, maker of one of the two vaccines authorized in the United States.
British scientists said late last week that they have preliminary evidence suggesting that the U.K. variant may be about 30 percent more lethal than the more common strain of SARS-CoV-2. The researchers emphasized that this is a new variant and that they are still trying to understand its clinical effects. The scientific community has not produced evidence that the South Africa or Brazil variants cause a different level of disease severity.
But the Brazil and South Africa variants have incited particular concern among scientists because they contain mutations that may allow the virus to evade the effects of some antibodies, such as the monoclonal antibodies developed as therapies for patients with covid-19, the illness caused by the virus.
“This is the new reality of covid,” Osterholm said. “This is now the dawning of the age of the variants.”
This article has been corrected to say that the Brazil variant was detected through nasal swabs.
Lena H. Sun contributed to this report.