A major flu vaccine campaign is being launched for US farm workers as concerns mount over the spreading bird flu virus in the agricultural sector, with the US Centres for Disease Control and Prevention (CDC) hoping the jab will help to prevent healthcare strain and combat potential mutations from the highly pathogenic bird virus.
Part of the campaign will seek to combat disinformation about vaccines, which has hampered previous efforts, reports The Guardian.
While there are about 200 000 livestock workers in the US (this excludes unofficial workers), vaccination rates within the industry are uncertain. On average, only 47% of Americans get the flu shot each year.
Nirav Shah, principal deputy director of the CDC, said he was optimistic the vaccine campaign would be successful.
“Many agricultural and livestock workers come from countries where vaccination is very commonplace, well-accepted and rates are high,” he said. If farm workers do have low rates of vaccination, “the reason is access, not reticence”.
The $5m campaign will bring seasonal flu shots to the employees and another $5m will go toward strengthening healthcare for them, including improved access to testing, treatment and personal protective equipment.
The campaign will distribute the seasonal flu shot – but not an H5N1-specific vaccine for bird flu – among communities that may have limited access to healthcare.
The US ordered 4.8m doses of an H5N1 vaccine in May, and vials are now coming off the production line. The country has also entered into an agreement with Moderna to produce an mRNA vaccine for bird flu, expected to begin trials in 2025.
The new vaccines have not yet been approved by the Food and Drug Administration (FDA), though there are options to use medications before clinical trials are complete through the FDA’s expanded access programme for people at high risk of severe illness or death.
Officials maintain the bird flu vaccines are not recommended for anyone at this time, while acknowledging the higher risk for farm workers compared with the general public.
For farm workers and close contacts of people who test positive, the CDC is instead recommending flu antivirals: pre-approved drugs that may work better to block transmission than flu vaccines typically do. Antivirals may be used before or after a person is exposed to a virus.
In 2022, the flu shot prevented 6m illnesses, 65 000 hospitalisations and 3 700 deaths, according to the CDC.
Officials also hope the seasonal flu jab will reduce the chance of co-infection – when someone gets sick with multiple strains of flu at the same time. While the flu shot doesn’t prevent all infections, it can lower the risks.
The seasonal flu shot could thus help prevent reassortment, where a worker might get bird flu and human flu at the same time and mix them to make an even worse variant.
“In theory, reassortment 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,” Shah said.
The new campaign will focus on increasing access, but strategies may differ depending on the state, Shah said. States may work with local healthcare providers and county health departments, they could go directly to farms and they could set up clinics and vaccination tents at social gatherings, churches, fairs and community centres.
There are a few reasons US officials don’t recommend the bird flu vaccine for people yet, Shah said. So far, no one in the US has been hospitalised or died from H5N1, despite a global 50% mortality rate from this strain.
The main symptom has been conjunctivitis, or pink eye, though some patients have developed more typical flu symptoms like coughing and sore throat.
The virus also isn’t showing mutations to become more transmissible among people, and there isn’t evidence that the virus is spreading from person to person, though testing remains very limited.
Health officials seem to see the US outbreak as a series of anomalies: no one has got very sick yet; they believe they can arrest the spread in livestock. A recent spate of cases among poultry workers in Colorado, where nine people tested positive, may be attributed to unusually high heat, making personal protective gear less effective, they say.
They weigh these concerns, which they see as relatively unusual, against longer-term issues like the spread of misinformation that may result in vaccine hesitancy.
“Anything that happens after vaccination, whether caused by the vaccine or not, would and could be attributed to the shot, at least in the minds of the public,” Shah said. “And that could destroy confidence in that vaccine. It could destroy confidence in all vaccines for a number of years.”
In 1976, for example, an outbreak of a pandemic-potential swine flu led to a widespread vaccination campaign that was soon engulfed in misinformation. An extremely rare side effect, Guillain-Barré syndrome, emerged – but that’s not what engendered scepticism, Shah said.
Several people had heart attacks after getting their vaccines in the same location. An investigation later ruled out a connection to the vaccine – “people have heart attacks”, Shah said – but the association was already set among the public.
Similar anti-vaccine sentiment exploded from the fringes into the mainstream during the Covid pandemic. Some misinformation campaigns falsely attributed illness and death to vaccines.
“What’s different here is that this would be a new vaccine, and with anything new – Covid vaccines, a new drug, a new surgical procedure – all eyes are on that,” Shah said. “Do the benefits outweigh the risks?”
Meanwhile, farm workers and others in close contact with animals continue to face elevated risks of bird flu.
The CDC recently changed its procedures to make flu antivirals like Tamiflu easier to access.
“Tamiflu is a very viable option before we get to this point of vaccination, and we are embracing it,” Shah said. “On any kind of farm setting where any worker has been exposed, we have recommended it.”
See more from MedicalBrief archives:
American gets bird flu from infected cow
Bird flu hits third US farmworker but symptoms differ