A leading French infectious disease expert has warned that the bird flu virus currently circulating among wild birds, poultry, and mammals could spark a pandemic even more severe than COVID-19 if it evolves to spread between humans.

Speaking to Reuters, Marie-Anne Rameix-Welti, medical director of the Institut Pasteur's Respiratory Infections Centre, said the highly pathogenic avian influenza (H5) poses a significant global threat if it adapts for efficient human-to-human transmission.

The bird flu virus—responsible for the culling of hundreds of millions of birds in recent years—has disrupted food supplies and contributed to rising global prices. While human cases remain rare, the virus’ continued spread in mammals has heightened alarm among scientists.

“What we fear is the virus adapting to mammals, and particularly to humans, becoming capable of human-to-human transmission,” Rameix-Welti said. “And that virus would be a pandemic virus.”

The Institut Pasteur, known for rapidly developing and sharing COVID-19 detection protocols with the World Health Organization (WHO) in 2020, is closely monitoring H5 strains for early signs of dangerous mutations.

Rameix-Welti emphasized that unlike seasonal influenza strains such as H1 and H3—against which people have some antibodies—humans have no natural immunity to H5 bird flu viruses.

This situation mirrors the early stages of COVID-19, when the global population had no pre-existing protection. But she warned that a bird flu pandemic could be even deadlier.

“Flu viruses can kill healthy individuals, including children,” she noted. “A bird flu pandemic would probably be quite severe, potentially even more severe than the pandemic we experienced.”

Human infections with H5 strains have occurred in the past, largely due to close contact with infected birds or animals. The current H5N1 strain circulating in U.S. poultry and dairy cows has caused several human cases.

This month, the first-ever human case of H5N5 was detected in Washington state. The infected man, who had underlying health conditions, died last week.

According to the WHO’s latest report, nearly 1,000 human H5 infections were recorded between 2003 and 2025—mainly in Egypt, Indonesia, and Vietnam—of which 48% were fatal.

While no sustained human-to-human transmission has been observed, global health agencies say the virus’ rapid spread among mammals increases the likelihood of adaptation.

Researchers warn that early detection, expanded surveillance, and preparedness will be crucial to prevent another global health crisis. (ILKHA)