Federal public health officials are investigating a “large and sudden” outbreak of influenza among students at the University of Michigan, the university announced this week.
Since October, there have been 528 cases of flu on campus in Ann Arbor, a vast majority – 77 percent – occurring in students who have not been vaccinated against the flu. The spread of the disease has accelerated over the past few weeks, according to the university.
Experts from the federal Centers for Disease Control and Prevention were on campus this week to help university officials and local health authorities analyze the outbreak and evaluate the effectiveness of this year’s flu vaccines.
Emily Martin, an associate professor of epidemiology at the university’s School of Public Health who helps with the survey, said the current count of cases is significant, especially compared to those of recent years. She added that the university could identify more flu cases this year because students were looking for tests on symptoms that overlap with Covid-19.
“It’s a great opportunity to get a good early signal of what vaccine effectiveness is now, what strains are circulating, what it could anticipate for the rest of the country,” Dr. Martin said.
Nationally, the rate of flu infection remains low, but the CDC said this week that it has received reports of a spread among university adults. Epidemics like the one at the University of Michigan represent the “first significant” activity of this year’s flu season, the agency said in a statement. Influenza season generally begins in October and can last until May, the agency said.
Kate Grusich, a spokeswoman for the agency, said the University of Michigan boom is the only university campus investigation the CDC is currently involved with.
The university and the local health authorities have asked for the agency’s help, Dr Martin said, adding that the investigation was a joint effort.
In Michigan, 2.2 million doses of flu vaccine have been administered this year, a figure that represents about 22 percent of the state’s population, according to state data. Vaccination rates were delayed in each age category compared to those of the previous two years.
In Washtenaw County, which includes Ann Arbor, about one in three residents is vaccinated against the flu, data show.
About 43.2 million flu vaccinations were administered nationally in pharmacies and doctors to people 18 or older by the end of October, Ms. Grusich said. About 62.4 million doses were administered in the same time period last year, she said.
Experts said last year’s flu season was mild compared to those of previous years, as the precautions people took to slow the spread of the coronavirus, including masking and social distance, helped prevent the spread of the flu.
Dr Martin said the university had heard from students who were confused about how the flu vaccine and the Covid-19 vaccines might interact. She encouraged students to receive both vaccines, emphasizing that they have particular benefits.
“One doesn’t replace the other,” she said.
A recent survey by the National Infectious Disease Foundation found that four out of 10 Americans are unsure about the flu vaccine or did not plan to get it. About a third of the 1,000 people surveyed reported having greater concerns about getting Covid-19 than the flu.
But experts have warned that this year could be different and that little is known about the interaction of Covid-19 and the flu. The CDC recommends that everyone aged 6 months or older receive a flu vaccine.