State health officials in Michigan said they have identified 246 fully vaccinated people who contracted the coronavirus between January and March, and three have died.
Lynn Sutfin, a spokeswoman for the state health department, said those individuals had a positive test 14 or more days after the last dose in the vaccine series, but some may ultimately be excluded because of a prior infection where they still tested positive after being vaccinated.
“We expect to see breakthrough cases with any vaccination, including all the COVID-19 vaccines. The number of potential cases identified to date is not in excess of what might be expected with vaccines with 95 percent efficacy,” Suftin said in a statement.
To date, nearly 2 million Michiganders have completed their COVID-19 vaccine regimen with either two doses of mRNA vaccines, or a single dose of the vaccine from Johnson & Johnson, which is about 19.5 percent of the population.
According to the state, the cases are undergoing further review to determine if they meet other criteria from the Centers for Disease Control and Prevention (CDC) for “breakthrough” designation, including the absence of a positive antigen or PCR test less than 45 days before their post-vaccination positive test.
Of the 246 potential breakthrough cases from Jan. 1 through March 31, 117 had data entered about hospitalization status. Of those people, 11 were hospitalized.
The three deaths all occurred in people 65 years or older, two of which happened within three weeks of full vaccination.
“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,” Suftin said.
Vaccination does not completely protect someone from being infected with COVID-19, but it dramatically lowers the chance of developing a severe or even fatal case.
“It is important to reiterate that, while the overall numbers of potential breakthrough cases are low, the proportions of those symptomatic, hospitalized, and who died are all lower than those who are unvaccinated,” Suftin said.
Sutfin added that test samples are undergoing genomic sequencing to see whether any of the cases were caused by a more contagious variant, but results are not back yet.
State officials have identified five variants of the coronavirus circulating, with the B.1.1.7 variant first found in the United Kingdom the most prominent. The variant is much more contagious than the original “wild-type” virus.
Michigan has the highest per capita rate of new cases in the country, and has seen hospitalizations spike from around 900 statewide at the beginning of March to almost 2,000 by the end of the month, according to data from the Covid Act Now tracking site.
According to the site, the state is averaging nearly 67 new cases for every 100,000 people. The positivity rate is over 15 percent percent, and continues to climb.