To prevent a new supercharged flu virus, CDC pushes seasonal flu vaccines to farmworkers at risk for co-infection with bird flu
The goal of the initiative is to protect the health and safety of livestock workers as seasonal respiratory viruses begin to circulate, Dr. Nirav Shah, principal deputy director of the CDC said Tuesday.
“Preventing seasonal influenza in these workers, many of whom are also potentially exposed to H5N1 viruses may also reduce the risk of new versions of the influenza A virus emerging,” Shah said at the news conference.
If two different strains of the flu infect a person there is always a risk that the viruses could mix together and create a completely new virus with a mix of traits from each one. A new virus could emerge that could be harmless, but there is also a chance that a new virus could be even more contagious, deadly or resistant to existing treatments.
The risk of what is called genetic reassortment – when multiple viruses co-infect the same cell and replicate to create a new virus – is “theoretical,” Shah said, but “because we know that it could happen, we want to take steps now to reduce that effect.”
“Anything that is predictable is also something that’s preventable,” Shah said.
Reassortment has happened with other influenza viruses. In 2009 H1N1, what Shah described as “a close cousin” of H5N1, was thought to have emerged because of genetic reassortment of influenza A viruses in pigs.
“I’m not suggesting that it was a human-pig interaction that led to that reassortment, but it was thought to be a reassortment-type event between a novel H1 virus and a more seasonal variety,” Shah said. “This is something that has occurred and it’s a concern for that reason. Anything we can do to reduce the likelihood that a new virus that emerges that has the transmissibility of seasonal flu with the severity of H5 is a risk that we want to reduce as much as possible.”
The CDC said with this new initiative, the seasonal flu vaccine will not be mandatory for farm workers. Public health officials on a state-level will bring vaccines to workers at local events and to areas where farm workers typically gather.
“This is fundamentally an effort that relies upon trust and that trust relies upon us making the case for why the vaccine is important,” Shah said.
The seasonal flu vaccine does not provide protection against bird flu. The CDC said it still does not think a specific bird flu vaccine is necessary even among workers that are at a higher risk who work with infected animals.
While there have been additional cases in humans with the outbreak, Shah said, symptoms have been mild and the prevalence is still “extremely low” and does not warrant a H5 specific vaccination.
The CDC announced an additional $4 million will be sent to the National Center for Farmworker Health to help prevent more workers from getting sick with bird flu. The federal organization will use the money to partner with community-based organizations in impacted states. Together the organizations will provide training and information sessions about bird flu and the organizations will expand access to testing, treatment and PPE.
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The CDC said Tuesday that there are nine known human cases of H5N1 among poultry workers in Colorado related to the latest outbreak.
Earlier the CDC said that the workers who got sick had been culling poultry believed to be infected at a farm in the northeast part of the state.
The latest human cases are mild. Most people who are sick have pink eye. The CDC said there are no additional tests pending, but there still could be additional cases.
There have been a handful of cases in other states including in Texas and in Michigan. All were farm workers.
The general public’s risk of getting sick with bird flu still remains low, according to the CDC. The is still a real risk for animals. The outbreak has impacted millions of animals with outbreaks in commercial poultry and in back yard flocks, cows, wild birds, wild mammals and some cases among pets, mostly among cats.
Maintaining the health of livestock workers is crucial during seasons when respiratory viruses circulate, as it can reduce the risk of genetic reassortment and the emergence of potentially harmful new virus strains. Dr. Nirav Shah emphasized that while genetic reassortment is theoretical, it has occurred in the past with influenza viruses, such as the 2009 H1N1 outbreak.
