Michigan research finds no asymptomatic carriers of H5N1 in humans

LANSING — A Michigan-led study has found no evidence of antibodies against H5N1 in the blood of 35 workers from two dairy farms, according to an update on the virus by the Centers for Disease Control and Prevention.

The research is important as it suggests that asymptomatic infection in people is not occurring, the update concluded.

The Michigan Department of Health and Human Services will continue the research and is partnering with the CDC to analyze the data. A manuscript will be prepared for peer-review publication.

The CDC reported Friday that the number of human cases in the United States has risen to 12 since 2022. The most recent cases have been in Colorado. Human cases were also previously identified in Michigan and Texas.

Forty-eight states have seen outbreaks in poultry, totaling nearly 100,406,000 birds. Thirteen states, including Michigan and Ohio, have seen a total of 163 dairy herds affected by the virus this year. All 50 states have reported H5N1 in wild birds.

“H5N1 virus is widespread among wild birds and continues to cause outbreaks in poultry and spillover to mammals,” said Alicia Budd, leader of the CDC’s National Surveillance and Outbreak Response Team. “We are monitoring the virus itself for any mutations.”

Ms. Budd noted that 1,390 people have been monitored since H5N1 was detected in dairy cows, with 60 of those tested for the virus.

“We continue to believe the risk to the public remains low,” she said.