CDC to Provide Farmworkers With Seasonal Flu Shots to Prevent Co-infection With Bird Flu

‘In theory, reassortment could lead to a new influenza A virus that could pose a significant public health concern,’ the CDC’s Nirav Shah said.

A person holds a test tube labelled Bird Flu, in this picture illustration, on January 14, 2023. Dado Ruvic/Reuters

The U.S. Centers for Disease Control and Prevention (CDC) said it is funding a $5 million program to provide seasonal flu vaccines to livestock workers. The initiative aims to reduce the risk of potential co-infection of both seasonal influenza and the bird flu virus, also known as H5N1, in farm workers.

Infection with both viruses could lead to a genetic reassortment, where genetic material from the two influenza viruses mixes and creates a new influenza virus, according to the CDC.

“In theory, reassortment could lead to a new influenza A virus that could pose a significant public health concern by becoming more efficient at spread and potentially more severe. A virus that has the transmissibility of seasonal influenza and the severity of H5N1,” the CDC’s principal deputy director, Nirav Shah, said during a July 30 press call.

Shah acknowledged that dual infections are rare but said the agency aims “to do everything we can” to reduce the risk of a new virus emerging from such infections.

He said vaccination against seasonal flu will also help to reduce the strain on hospitals and health centers in the fall and winter “when influenza and other respiratory viruses are circulating.”

Shah said the CDC will spend another $5 million on outreach and education initiatives to help curb bird flu infections among farm workers. From this, $4 million will be allocated to the National Center for Farmworker Health to train and educate farm workers on preventing bird flu, while the remaining $1 million will fund the NIOSH Centers for Agricultural Safety and Health.

Shah noted that a total of nine poultry workers in Colorado have tested positive for avian influenza as of July 30, including three cases detected last week. The CDC said the workers developed mild symptoms.

This brings the number of human cases of bird flu in the United States since April to 13. The CDC said the risk to the general public from avian flu remains low.

“There are no signs of unexpected increases in flu activity otherwise in Colorado, or in other states affected by H5 bird flu outbreaks in cows and poultry,” the agency said in a July 25 statement. “To date, we have not seen genetic changes in the virus that would make it more likely to transmit between humans, but we are closely monitoring it.”

The CDC sent a team to Colorado last month after bird flu infections were detected among poultry workers. Colorado Gov. Jared Polis declared a disaster emergency on July 15 to assist affected facilities with response efforts.