First came Omicron, then its highly infectious subvariant, BA.2. That subtype gave rise to subtypes of its own, with an increasing share of new cases in the US. Coronavirus is constantly mutating. While some variants seem to be disappearing, others continue to run into major outbreaks. Experts say a new form, BA.2.12.1, is spreading rapidly and will likely become the dominant form of the virus in the US in the next weeks. There is no indication yet that leads to more serious disease.
In the week ending Saturday, BA.2.12.1 made up about 36% of all new cases in the US, according to US CDC estimates. This is up from 26% of cases a week ago and 16% of infections during the second week in April. First detected by New York state health officials in April, BA.2.12.1 is spreading more quickly than earlier versions of the Omicron version, causing a huge spike in cases over the winter. This version descends from BA.2 and appears to have spread even more rapidly, although the reasons are still being investigated. “Omicron was more permeable than delta, which was more permeable than alpha,” said Christa Queen, director of viral genomics at Louisiana State University. He said that BA2.12.1 is building on that trend.
According to the NYT database, reports of new cases have doubled nationally in the past month as the Omicron subvariant spread. In the last two weeks, the total cases have increased by 50%. But reported cases are less likely as access to home tests has increased. Nevertheless, almost every reported infection is from an omicron subvariant, and although BA.2 is still the dominant form, BA.2.12.1 is rapidly advancing. Hospitalization rates have risen gradually – up to 18% in two weeks – but those rates lag behind. There has been a 17% reduction in deaths in the last two weeks.
In the week ending Saturday, BA.2.12.1 made up about 36% of all new cases in the US, according to US CDC estimates. This is up from 26% of cases a week ago and 16% of infections during the second week in April. First detected by New York state health officials in April, BA.2.12.1 is spreading more quickly than earlier versions of the Omicron version, causing a huge spike in cases over the winter. This version descends from BA.2 and appears to have spread even more rapidly, although the reasons are still being investigated. “Omicron was more permeable than delta, which was more permeable than alpha,” said Christa Queen, director of viral genomics at Louisiana State University. He said that BA2.12.1 is building on that trend.
According to the NYT database, reports of new cases have doubled nationally in the past month as the Omicron subvariant spread. In the last two weeks, the total cases have increased by 50%. But reported cases are less likely as access to home tests has increased. Nevertheless, almost every reported infection is from an omicron subvariant, and although BA.2 is still the dominant form, BA.2.12.1 is rapidly advancing. Hospitalization rates have risen gradually – up to 18% in two weeks – but those rates lag behind. There has been a 17% reduction in deaths in the last two weeks.
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