Analysis – Scientists wary of bird flu pandemic ‘slowly unfolding’ By Reuters

Written by Julie Steenhuysen and Jennifer Rigby

CHICAGO/LONDON (Reuters) – Scientists tracking the spread of bird flu are increasingly concerned that gaps in surveillance could keep them from tracking a new pandemic, according to Reuters interviews with more than a dozen leading epidemiologists.

Many of them have been monitoring the new strain of H5N1 bird flu in migratory birds since 2020. But the spread of the virus in 129 dairy herds in 12 states in the US shows a change that could bring it closer to human transmission. The infection has also been found in other mammals, from alpacas to house cats.

“It looks like the epidemic is slowly progressing,” said Scott Hensley, a professor of microbiology at the University of Pennsylvania. “Right now, the threat is very low … but that can change in a heartbeat.”

At the start of a human jump warning, health officials around the world can quickly take steps to protect people by introducing improved vaccinations, comprehensive testing and management methods.

Federal inspection of US dairy cattle is currently limited to inspecting herds before crossing state lines. The state’s testing efforts are inconsistent, while testing of people exposed to sick cattle is scant, government health officials and pandemic flu experts told Reuters.

“You have to know which farms have HIV, how many cows have HIV, how much the virus spreads, how long these cows stay infected, the mode of infection,” said Dutch influenza pathologist Ron Fouchier of the Erasmus Medical Center. in Rotterdam.

Dr. Jeanne Marrazzo, director of the US National Institute of Allergy and Infectious Diseases, said human surveillance is “very limited.”

Marrazzo described the US Centers for Disease Control and Prevention’s human flu screening network as “a passive reporting system, just a presentation system.” The US Department of Agriculture is very active in inspecting cattle, but does not disclose to the public which farms are affected, he said.

Several experts say different approaches from animal and human health organizations can hinder a quick response.

“If you were designing a system from scratch, you would have one facility,” said Gigi Gronvall, a biosecurity expert at the Johns Hopkins Center for Health Security. “This is not the only example where we have environmental or animal problems causing human problems.”

A USDA spokesperson said the agency is working “around the clock” with the CDC and other partners in a “government-wide response,” adding that ongoing research shows that “America’s food remains safe, sick cattle usually recover after a few weeks, and the risk to human health remains low.” “

The CDC said in a statement, “The USDA, and state and local health departments across the country have been preparing for the evolution of the influenza virus for nearly two decades and are constantly monitoring the smallest changes in the virus.”

‘CAUTION PIECE’

Some pandemics, including COVID-19, come with little warning. In the last flu pandemic, caused by H1N1 in 2009, the virus and its predecessors had been circulating among animals for several years, Hensley said, but more surveillance would have helped health officials prepare.

Three people in the US have tested positive for H5N1 bird flu since late March after contact with cattle, which have mild symptoms. One person in Mexico was infected with a variant of H5 that had never been seen in humans before, and without exposure to animals. Other cases were reported in India, China and Australia, caused by different species.

The World Health Organization says the risk of H5N1 to humans is low because there is no evidence that the infection is caused by humans. Other tools are available if that changes, including limited amounts of the existing H5N1 vaccine and antibiotics like Tamiflu.

There are ways to launch large-scale production of tests, treatments and vaccines, if needed, said the UN’s influenza chief, Wenqing Zhang.

Some experts say there is enough initial concern to prepare for a possible spread to people, although the reasons for action vary according to the role played in the response, said Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations (CEPI). His organization has worked early on funding the development of a vaccine for COVID, and he is now in discussions with research partners about H5N1.

CEPI aims to build a library of prototype vaccines for pandemic-potential viruses. This will help drug makers to start mass production and distribute images where needed within 100 days of an outbreak.

Some countries are taking steps to protect people from H5N1. The United States and Europe are getting “pre-pandemic” flu vaccine doses that can be used in high-risk groups, including farm or laboratory workers. Finland is expected to be the first country to vaccinate wool and poultry farm workers, as well as animal health workers.

Expanding vaccine access is also complicated, says WHO’s Zhang. Manufacturers of the potential pandemic flu vaccine are making the seasonal flu shot and cannot produce both at the same time, he said.

Since most flu vaccines are made using a virus grown in eggs, it can take up to six months to produce a pandemic vaccine. The US is negotiating with it Moderna (NASDAQ:) to apply their rapid mRNA technology to the influenza pandemic.

Experts all agreed on the need to balance acting quickly to avoid the threat versus overreacting.

“We want to be cautious,” said Wendy Barclay, an epidemiologist at University College London who researches bird flu for the UK Health Security Agency, “without saying the world is about to end.”