Although health officials say the risk of H5N1 bird flu infection is still low for the general population, they announced on Monday a $5-million plan to offer seasonal flu vaccine to livestock workers.
Nine poultry workers in Colorado are reported to have been infected; the symptoms were described as “mild,” with conjunctivitis, or pink eye, as the predominant symptom. The official case total across the U.S. since April now stands at 13.
“These cases highlight that certain groups who focus on depopulating” — like the poultry workers in charge of killing the animals — “are at heightened risk of infection,” said Nirav Shah, principal deputy director at the U.S. Centers for Disease Control and Prevention.
Officials said they are launching this program for seasonal flu vaccine to protect the health of farmworkers, and also to reduce the chance of a human flu mixing with an H5N1 virus, which could ignite a new pandemic threat.
The reassortment and recombining of flu viruses is a concerning scenario.
The 1918 “Spanish flu,” which killed more than 50 million people worldwide, was likely the recombined product of a human and avian flu. So too was the 2009 H1N1 swine flu, which led to a pandemic estimated to have caused the death of more than 280,000 people across the globe.
“We’ve seen that livestock workers are at risk for H5 infection because of their exposure to animals,” Shah said. “They are also at risk for infection with seasonal flu. … As such, it’s possible that they could be coinfected with both seasonal influenza viruses … and with H5 virus.”
He said that although such dual infections are rare, they could “potentially result in an exchange of genetic material between the two different influenza viruses … that could lead to a new influenza virus that could pose a significant public health concern, a virus that has the transmissibility of seasonal influenza and the severity of H5N1. We want to do everything we can to reduce the risk that the virus may change because of this coinfection and reassortment.”
Shah said health officials are not considering offering a vaccine for H5N1 bird flu because so far it hasn’t been associated with severe illness or with transmission between people.
The seasonal vaccination program will be established in states that have been affected by the H5N1 in both cow and poultry populations.
California has not had any reported infections in dairy herds; however, several poultry farms and wild birds have been struck by the virus in recent months and years.