U.S. begins testing bird flu vaccines for poultry after record outbreak

The trials, conducted by the U.S. Department of Agriculture's (USDA) Agricultural Research Service, are the first step in a lengthy process toward the possible first use of vaccines to protect U.S. poultry from the lethal virus.

Bird flu, also known as highly pathogenic avian influenza (HPAI), has killed hundreds of millions of birds around the world, raising interest in vaccines. The virus is largely spread by wild birds that transmit it to poultry.

The USDA is testing one vaccine from Zoetis Inc, one from Merck Animal Health, and two developed by the department's Agricultural Research Service.

Zoetis said it previously supplied its vaccine to a USDA stockpile in 2016, following a massive 2015 outbreak, but it was never used.

Initial data from a study using a single dose of a vaccine are expected in May, while results from studies on two-dose vaccine regimens are expected in June, the USDA said.

If the trials are successful and USDA decides to continue development, it would take at least 18-to-24 months for a vaccine that matches the current virus to be commercially available, the agency said.

The government needs to ensure vaccinations would not disrupt trading with major buyers, said Greg Tyler, president of the industry group USA Poultry & Egg Export Council.

Governments have previously focused on culling infected flocks to control the virus due to concerns importers would block shipments of vaccinated poultry to avoid the risk of infections.

The USDA said on Friday its "current strategy of stamping out and eradicating HPAI... continues to be the most effective strategy because it works."

France said last week it was launching an order for 80 million doses of vaccines to use in ducks in the autumn if final trial results are positive, the first EU member to start such a plan.

China reports first human death due to H3N8 bird flu

The WHO says the woman, who died in March, probably contracted the virus at a live poultry market and the risk of further spread is low.

A 56-year-old woman in southern China has died after testing positive for H3N8 avian influenza, marking the first human death from that strain of bird flu, according to the World Health Organization (WHO).

While H3N8 is “one of the most frequently found” subtypes of flu in birds, it had not been detected in humans before two cases emerged in April and May last year, both in China.

In a statement, the WHO said the woman, who had pre-existing medical conditions including cancer, had been admitted to hospital with severe pneumonia after falling ill in February. She died last month.

“The case was detected through the severe acute respiratory infection (SARI) surveillance system. No close contacts of the case developed an infection or symptoms of illness at the time of reporting,” WHO said in its statement on Monday.

All three people who contracted H3N8 in China are thought to have been exposed to the virus at live poultry markets. The United Nations health agency said the Chinese government had stepped up monitoring for the strain and that the risk of more infections was low.

“However, due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance to detect virologic, epidemiologic and clinical changes associated with circulating influenza viruses which may affect human (or animal) health,” it said.

The H3N8 infection is unrelated to the H5N1 bird flu pandemic, which has devastated poultry and wild birds around the world in the last 18 months and has spread to mammals including foxes, bears and domestic cats.

To infect humans, the H5N1 virus has to attach itself to receptors in the lungs, which the virus lacks the ability to readily bond with, William Schaffner, a professor of medicine at Vanderbilt University’s Division of Infectious Diseases, told Al Jazeera in February.

Forced adaptation to replicating in the lungs is why only poultry workers, who breathe in contaminated faecal dust, are typically infected, Schaffner added.

The H3N8 virus is less dangerous for both wild birds and domestic poultry than H5N1, and is known to have been circulating since 2002 after first emerging in North American waterfowl.