Finland is preparing to offer vaccines to people at risk of exposure to an avian influenza strain spreading among farmed and wild animals, health officials there said, potentially becoming the first country to take such a step as concerns about the threat the virus poses to people intensify.

The vaccine campaign will be limited, with doses set to be available to groups including poultry farmers, veterinarians, scientists who study the virus, and people who work on fur farms housing animals like mink and fox and where there have been outbreaks. In an email, Mia Kontio, a health security official at the Finnish Institute for Health and Welfare, told STAT the country was waiting for 20,000 doses to arrive, but planned to administer them “as soon as the vaccines are in the country.”

The decision to start providing vaccines reflects fears that people in close contact with infected animals could contract the H5N1 virus themselves. The virus is, for now, not particularly adept at infecting humans or, more importantly, spreading among them. But scientists worry that as the virus infects more mammalian species, and if it encounters more human cells, then the higher the chances are that it evolves to become more of a threat to people.

The Finnish campaign also comes as the U.S. faces an H5N1 outbreak among dairy cattle — previously a species scientists thought wasn’t susceptible to the virus. Three dairy workers have had confirmed infections tied to the outbreak, and although the infections were all mild and there were no signs of forward transmission to other people, the cases underscored the risk to people who have contact with infected animals.

“The concern here is about the animal-human interface,” said Marc Lacey, the global executive director for pandemic at CSL Seqirus, the maker of several H5 vaccines, including the one Finland is planning on using.

Other countries are discussing deploying H5 vaccines or are working to secure supplies, Lacey said. The U.S., for example, last week hired CSL Seqirus to build up the number of H5 flu vaccine doses it has available. But Finland was the first country he knew of that actually planned to use the vaccine, at least in recent years outside research studies.

The vaccine to be administered in Finland is designed off a different avian influenza virus called H5N8, but researchers say the shot should still confer protection against H5N1. It’s the hemagglutinin component of the vaccine — the H part — that’s the main target. The vaccine also includes an adjuvant, a component that deepens the generated immune response.