China has reported a fatal H5N6 avian flu infection in a 52-year-old woman from Fujian province in the southeastern part of the country.

Hong Kong's Centre for Health Protection (CHP) said the woman's symptoms began on April 13, and she was hospitalized on April 20, where she died on April 30. An investigation found that she had been exposed to backyard poultry before she became ill. 

The woman was from Quanzhou, Fujian province's largest city, which has a population of more than 8 million.

China's 90th case in a decade

Highly pathogenic H5N6 is known to circulate in poultry from China and other Asian countries, but so far, China and Laos are the only nations that have reported human cases. Human cases are rare and mostly occur in people who have contact with poultry or poultry environments. The infections are often severe or fatal. 

China has now reported 90 H5N6 cases since the first human illness was reported in 2014. The country reported its last case in the middle of January.

Immunity obtained through infections and post-exposure vaccination—not preventive vaccination—was likely the driving force of reduced mpox transmission in the Netherlands in 2022, according to new work from the Dutch National Institute for Public Health and the Environment (RIVM) published late last week in Eurosurveillance. The researchers also say behavior change also likely played a role.

The Netherlands reported its first mpox case on May 20, 2022, at the beginning of a global outbreak, and by December 31, 2023, a total of 1,294 cases had been documented.  As in other countries, 94% of cases were among men who have sex with men (MSM), and 99% of cases occurred in males. 

The primary preventive vaccination (PPV) program was launched on July 25, 2022, but the researchers showed that cases were already declining by early July among MSM.

Vaccine protection almost 70%

Overall, 29,851 PPV doses were administered from July 25, 2022 to April 30, 2023. The overall vaccine uptake rate was 45.8%, with 35.4% of the target population being fully vaccinated. The effectiveness of preventive vaccination was estimated at 68.2%.

The authors said the PPV program started at the peak of mpox transmission in the Netherlands.  

"By the time PPV would be effective, the incidence was already down to [about] five cases per day, making it unlikely that PPV contributed significantly to the decline of the outbreak," the authors said. 

The role of behavioural change could unfortunately not be adequately studied with the available data, but based on other studies it should not be ignored.

Infection-acquired immunity in a substantial proportion of those most at risk was the main factor in declining cases, with behavioral changes also likely playing a role, the authors concluded. "The role of behavioural change could unfortunately not be adequately studied with the available data, but based on other studies it should not be ignored," they noted.