Scientists fear bird flu. “A pandemic unfolding in slow motion”

Scientists tracking the spread of bird flu are increasingly concerned that gaps in monitoring could keep them a few steps behind when a new pandemic breaks out, according to Reuters interviews with more than a dozen leading experts.

Bird flu could break out unexpectedly PHOTO: archive

Many of them are monitoring the new H5N1 bird flu subtype in migratory birds from 2020. But the spread of the virus to 129 dairy herds in 12 US states signals a change that could bring the virus closer to becoming transmissible between humans. Infections have also been detected in other mammals, from alpacas to domestic cats, writes

“It almost seems like a pandemic in slow motion”said Scott Hensley, a professor of microbiology at the University of Pennsylvania. “Right now, the threat is pretty low. But that could change in an instant“, he warns.

The earlier the warning of a human jump, the sooner global health officials can take action to protect people by launching vaccine development, large-scale testing and containment measures.

Federal monitoring of US dairy cows is currently limited to testing herds before they are transported from one state to another. State testing efforts are inconsistent, while testing of people exposed to sick cattle is insufficient, government health officials and pandemic flu experts told Reuters.

“We need to know which are the positive farms, how many of the cows are positive, how well the virus spreads, how long these cows remain infected, the exact route of transmission,” emphasizes the Dutch virologist Ron Fouchier from the Erasmus Medical Center in Rotterdam.

Dr. Jeanne Marrazzo, director of the US National Institute of Allergy and Infectious Diseases, said monitoring in humans is “very, very limited”. Marrazzo described the US Centers for Disease Control and Prevention’s (CDC) human influenza surveillance network as “a passive reporting and presentation mechanismThe US Department of Agriculture is more proactive in testing cows, but does not publicize affected farms, she said.

Several experts pointed out that the different approaches of animal and human health agencies could prevent a faster response. “If I were to design the system from scratch, I would have only one agency“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,” mentions the expert.

A USDA spokesman said the agency is working “non-stop” with the CDC and other partners in a “whole-of-government response,” adding that ongoing research shows that “America’s food supply remains safe, sick cows generally recover after a few weeks, and the risk to human health remains low.”


In a statement, the CDC states that “The USDA and state and local health departments across the country have been preparing for nearly two decades for the emergence of a new flu virus and are constantly monitoring even the smallest changes in the virus.”

Some pandemics, including COVID-19, appear with few prior signs. In the last flu pandemic, caused by H1N1 in 2009, the virus and its predecessors first spread among animals for several years, Hensley says, but greater monitoring would have helped health authorities prepare.

Three people in the United States have tested positive for H5N1 bird flu since late March after coming into contact with cows and showing mild symptoms. A person in Mexico was infected with a separate H5 strain that had not been previously encountered in humans and with no known exposure to animals. Other cases have been reported in India, China and Australia, caused by different strains.

The World Health Organization states that the risk of H5N1 infection to humans is low because there is no evidence of human transmission. Some tools are available if that changes, including limited amounts of the existing H5N1 vaccine and antiviral drugs like Tamiflu. Mechanisms are in place to launch large-scale production of tests, treatments and vaccines if necessary, said Wenqing Zhang, head of the UN flu agency.


Other experts said there was enough cause for concern to start preparing for a potential spread to humans, although the triggers — to call for action — differed depending on the role played in the response, said Richard Hatchett, executive director of the Coalition for Innovations in Epidemic Preparedness (CEPI). His organization acted early to fund the development of the COVID vaccine, and is currently in discussions with research partners regarding H5N1.

CEPI aims to create a library of vaccine prototypes for pathogens with pandemic potential. This would help drugmakers start large-scale production and distribute vaccines where needed within 100 days of an outbreak.

Some countries are taking measures to protect the population against H5N1. The United States and Europe provide flu vaccine doses”pre-pandemic” which could be used for high-risk groups, including agricultural or laboratory workers. Finland is expected to become the first country to vaccinate fur and poultry farm workers, as well as animal health workers.

Expanding access to vaccines is also complex, said WHO’s Zhang. Manufacturers of potentially pandemic flu vaccines make seasonal flu vaccines and cannot produce both at the same time, she said.

Given that most flu vaccines are made using viruses grown in eggs, it could take up to six months to produce pandemic vaccines. The United States is in talks with Moderna to use their faster mRNA technology for pandemic flu vaccines.

All experts recognized the need to strike a balance between acting quickly to avoid a threat and overreacting. “We want to sound a note of caution without saying the world is about to end.”said Wendy Barclay, a virologist at University College London who researches bird flu for the UK’s Health Safety Agency.