Two hundred and forty six Michigan residents have tested positive for Covid-19 after being fully vaccinated, three of whom have died.
Health officials in the state stressed that a small proportion of people take longer than two weeks to develop antibodies after their second shot. Those who caught Covid after both jabs also could have caught Covid prior to vaccination or in the gap between the two shots.
Lynn Sutfin, a spokeswoman for the Michigan Department of Health and Human Services, told The Detroit News that the cases were reported between 1 January and 31 March and that all of them had a positive test at least two weeks after getting their final vaccine dose.
She said: “Some of these individuals may ultimately be excluded from this list due to continuing to test positive from a recent infection prior to being fully vaccinated.
“These cases are undergoing further review to determine if they meet other CDC criteria for determination of potential breakthrough, including the absence of a positive antigen or PCR test less than 45 days prior to the post-vaccination positive test.
“In general, these persons have been more likely to be asymptomatic or mildly symptomatic compared with vaccinated persons.”
The Michigan Department of Health had complete hospitalisation data for 117 of the cases, 129 were incomplete.
Ms Sutfin added: “Of the 117 with hospitalisation data entered, 11 were hospitalised, 103 were not hospitalised, and three are reported as unknown.”
She said that the three individuals who died were “all persons 65 years or older, and two of which were within three weeks of completion of vaccination”.
She added to The Detroit News: “While the majority of the population develops full immunity within 14 days of completion of their vaccine series, a small proportion appear to take longer to mount a full antibody response.
“CDC is actively working to better understand the risk characteristics of this group.”
Younger and healthier people have recently been hospitalised with Covid-19 in Michigan. Jim Dover, CEO and president of Michigan healthcare provider Sparrow Health System, told CNN that the rise in cases is being driven by fatigue and new variants of the virus.
He said: “This variant is more virulent, and so therefore more infectious, and so easier to catch.
“Second is everyone is tired of wearing masks, so you will go out and see a lack of social distancing, the lack of wearing masks. The virus is invisible and people did not know they’re walking through a cloud of Covid, and next thing you know, they’re infected.”
Covid-19 cases continue to rise in the state with over 11,000 cases reported on 5 April, according to data from The New York Times.
Michigan has surpassed 700,000 cases and is at the top of the country in new cases by population, The Detroit News writes. Hospitalisations are increasing at a faster rate than during the autumn when governor Gretchen Whitmer suspended indoor dining and in-person classes at Michigan high schools.
By 5 April, almost two million people out of the state’s almost 10 million residents had been fully vaccinated.