Over the last few days the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service has reported four more H5N1 avian flu detections in dairy cattle, two from California and two from Idaho, lifting the national total to 1,009 from 17 states since March 2024.

Also, APHIS has confirmed more H5N1 detections in poultry flocks from two states. They include two more detections in live bird markets in New York’s Queens County and a backyard location in Jefferson County. The virus was also detected at two locations in New Mexico, including a poultry farm in Curry County and a backyard flock in Roosevelt County.

WHO H5 surveillance guidance, USDA livestock disease funding

In other H5N1 developments, the World Health Organization (WHO) on April 11 released new guidance on surveillance for human infections with H5 avian influenza viruses.  It said the goal is to rapidly detect and characterize any human H5 infections to allow prompt response actions, assess trends and health risks, and guide global flu pandemic preparedness.

The group emphasized that under the International Health Regulations, countries are required to notify the WHO within 24 hours of any lab-confirmed human case involving a new subtype, based on the WHO case definition of being unusual or unexpected and potentially posing a serious public health impact. The new guidance also included a data reporting guide.

In a related US development, the USDA’s APHIS last week announced $15.3 million in funding for research projects to enhance preparedness, early detection, and rapid response to the diseases that threaten US livestock. The funding will support 68 projects led by 24 state agriculture departments, five tribal entities, 35 universities, three livestock groups, and one federal partner. One third of the funding is geared toward enhanced biosecurity. 

Older adults and other groups at risk for severe complications from influenza infections often do not receive flu antiviral prescriptions in urgent care (UC) and emergency department (ED) settings, according to a recent study in Clinical Infectious Diseases. 

The study was based on findings from 10,700 patient encounters for acute respiratory illness at urgent cares or emergency departments and with positive influenza virus test results during the 2023-24 flu season at four large US healthcare systems. 

All patients were considered higher risk for severe influenza, the median age was 65 years, with 59% female, 36% Hispanic, 37% non-Hispanic White, and 16% Medicaid recipients.

Overall, 58% were prescribed antivirals during their UC or ED visit, with 67% of prescribing occurring on the encounter date. Among those prescribed antivirals, 3,050 (80%) had them dispensed, with 65% of dispensing occurring on the prescription date. 

Those 50 to 64 had more antivirals dispensed

Among the 7,138 eligible encounters with an antiviral medication prescription, 7,135 (99.96%) were prescribed oseltamivir (Tamiflu).

Older age (65 and older) was associated with lower odds of same-day prescribing  (0.57; 95% confidence interval [CI], 0.42 to 0.78). For same-day dispensing, the odds were 0.58 (95% CI, 0.36 to 0.94), compared to those 18 to 49 years.

Those aged 50–64 years had the highest proportion dispensed antivirals (85%) among those prescribed,

"Patient encounters aged ≥65 years had the highest proportion prescribed antivirals (63%); however, those aged 50–64 years had the highest proportion dispensed antivirals (85%) among those prescribed,” the authors said. 

The authors said their study points to gaps in the antiviral prescription timeline.

"Strategies to improve earlier initiation of influenza antivirals for older, chronically ill patients along with expanded use of rapid and highly sensitive point-of-care testing in ED and UC settings could improve treatment initiation among patients with influenza," the authors concluded.

Valneva today announced that the Brazilian Health Regulatory Agency (ANVISA) has authorized its live attenuated single-dose chikungunya vaccine (Ixchiq) for use in people ages 18 and older, marking the first approval of a chikungunya vaccine in an endemic country.

Brazil has been the hardest hit country in the Americas, recording more than 1 million cases between January 2019 and July 2024. In its announcement, the company said the approval paves the way for large-scale clinical trials in Brazil, including phase 4 trials to generate more data on vaccine effectiveness in the wake of approvals in the United States and Europe.

Headway against a debilitating disease

The Coalition for Epidemic Preparedness Innovations (CEPI) is supporting those trials. Valneva said ANVISA continues to evaluate a chikungunya vaccine candidate that, if approved, will be made and distributed by Instituto Butantan in collaboration with Valneva.

Richard Hatchett, MD, CEPI’s chief executive officer, said Brazil’s approval is a significant step to expand the vaccine’s use for travelers as well as populations in chikungunya-affected countries. “ANVISA’s marketing authorization of the vaccine offers new hope in the fight against the debilitating disease and allows us to make headway in our goal to protect the tens of thousands in the country who suffer from chikungunya each year,” he said.