The government will spend $5 million to vaccinate livestock workers against the seasonal flu to prevent a potentially dangerous mingling of the seasonal and H5N1 avian flu viruses this fall, said the Centers for Disease Control on Tuesday. Nirav Shah, CDC principal deputy director, said there was “active discussion” of going a step farther, to give the H5N1 vaccine to workers culling flocks infected with bird flu, but that it was not warranted at present.
CDC and USDA officials declined to give a timeline for control of this year’s outbreak of bird flu in dairy cattle and infections of livestock workers from close contact with sick dairy cows and poultry. Thirteen workers have contracted mild cases of bird flu since April. Nine of them were laborers hired to kill and dispose of sick hens on two egg farms in northeastern Colorado.
“For right now, the seasonal flu vaccine is the right tool for the job,” said Shah during a teleconference. The vaccine will reduce the risk of serious illness from the seasonal flu virus and lessen the opportunity for the avian flu virus to pick up traits through coinfection that might make it more communicable or more virulent among people. “In public health, that [reduction of risk] is the name of the game,” he said.
There are an estimated 200,000 livestock workers in the United States. Nearly half of Americans get a seasonal flu shot, according to CDC data. A similar vaccination rate was possible among livestock workers, but the CDC will acquire enough vaccine to cover everyone, said Shah.
Vaccinations would begin at the same time this fall as for the general population ahead of flu season. The CDC will buy and provide the vaccine to states. Vaccinations will be voluntary.
The CDC says the risk of bird flu to the general population remains low because the H5N1 virus shows no sign of becoming more contagious, nor was there an increase in flu activity. Antiviral medications are effective in treating infections. To date, there have been no reported human-to-human infections.
“I think the question is, why do this?” responded Shah when asked if the H5N1 vaccine should be offered to livestock workers. The government is stockpiling an avian flu vaccine, but a number of hurdles, including FDA approval, must be crossed before vaccinations could start.
Later during the teleconference, Shah was asked about giving the H5N1 vaccine to the workers who cull infected poultry flocks because they seemed at greatest risk. “That is under active discussion,” he said. But he also said the antiviral medication Tamiflu was “a really good intermediate step.” A moment earlier, he said infections among livestock workers were “not to a threshold” where the vaccine would be useful.
For weeks, the CDC has recommended that people working with infected or potentially infected animals wear protective equipment. For a job like culling infected flocks, workers should wear water-resistant coveralls, masks, gloves, goggles, and boots. Compliance is difficult during hot weather and prolonged labor. “It is just a challenge to wear PPE at all times,” said Eric Deeble, USDA bird flu advisor.
“We believe we can arrest the spread of this disease and eradicate it on the farm,” said Deeble when asked if the outbreak would end this year. The USDA emphasizes strong biosecurity to prevent accidental transmission from farm to farm of the virus on equipment or clothing.
Responding to the same question, Shah described the seasonal vaccination drive among livestock workers as “preparedness. This is just public preparedness 101.”
Some 172 dairy herds in 13 states have been infected with the bird flu virus since late March, when the disease was first identified in cattle. Highly pathogenic avian influenza has killed nearly 101 million birds in domestic flocks, mostly egg-laying hens and turkeys being raised for meat, since the H5N1 virus appeared in the United States in February 2022.