This leads some authorities to attribute much of the increase to another culprit: variant B.1.1.7 of the virus, first identified in Britain, which proved to be more contagious and potentially more deadly than the original version that spread in the United States .
Federal health officials have expressed concern about the spread of variants, as the United States remains lagging behind in its attempts to track them down. Great Britain, with a more centralized health system, started a highly praised genetic sequencing program last year that enabled it to track the spread of variant B.1.1.7.
But efforts by the Centers for Disease Control and Prevention to locate variants have improved substantially in recent weeks and will continue to grow, largely because of the $ 1.75 billion in genomic sequencing funds in President Biden’s stimulus package sanctioned this month. Dr. Rochelle Walensky, the agency’s director, told lawmakers last week that between 10,000 and 14,000 test samples were being sequenced each week to find variants, and that the CDC was targeting about 25,000.
Michigan officials said this week that variant B.1.1.7 appeared in about one-eighth of the thousands of positive test samples the state has genetically analyzed so far this year. In mid-March, state health officials said Michigan accounted for 15% of all known cases of the variant in the United States, second only to Florida.
Dr. Lyon-Callo, the state’s chief epidemiologist, said this week that while variant B.1.1.7 certainly plays a role in increasing the rate of new cases, more than half of the 908 confirmed variant cases in Michigan result of a January outbreak in state prisons. This suggests that the variant is less widespread in the general population than the numbers may indicate.
Dr. Jennifer Morse, medical director for district health departments in 19 counties in the lower Michigan peninsula, said the nature of the outbreaks in the region suggests that the variant has spread far beyond the limited number of cases documented there.
“We had several outbreaks and some were very fast and big,” she said. “I feel it is very common in our area, looking at how our numbers are doing and how it is spreading.”