France’s Institut Pasteur warns that the avian influenza spreading through animal populations worldwide might spawn a health emergency surpassing COVID-19 in severity if the pathogen evolves to jump between people.
The highly pathogenic strain has already forced farmers to destroy hundreds of millions of birds globally. Food chains buckled under the pressure, and prices climbed. Yet human cases remain uncommon.
Marie-Anne Rameix-Welti directs the respiratory infections centre at Institut Pasteur. She explained the nightmare scenario researchers monitor daily.
“What we fear is the virus adapting to mammals, and particularly to humans, becoming capable of human-to-human transmission, and that virus would be a pandemic virus,” Rameix-Welti told Reuters.
Her institute earned recognition during COVID-19 by developing detection protocols early and sharing them with the World Health Organization and laboratories across continents.
Zero Natural Immunity Against H5
Human immune systems carry defenses against H1 and H3 seasonal strains. But H5 bird flu finds us completely vulnerable, similar to our initial exposure to COVID-19.
The comparison ends there. COVID-19 primarily threatened elderly populations and those with underlying conditions. Flu viruses show no such preference. They kill healthy adults and children with equal efficiency.
“A bird flu pandemic would probably be quite severe, potentially even more severe than the pandemic we experienced,” Rameix-Welti said from her Paris laboratory.
Historical records show numerous H5 infections in humans, including cases linked to the H5N1 strain currently circulating among American poultry and dairy cattle. Most victims worked directly with sick animals.
Washington state recorded the first human H5N5 case this month. The patient, who had pre-existing medical issues, died within days.
WHO data reveals nearly 1,000 human outbreaks between 2003 and 2025. Egypt, Indonesia, and Vietnam saw the highest concentrations. The mortality rate reached 48 percent.
Current Threat Assessment Remains Minimal
Gregorio Torres heads the Science Department at the World Organisation for Animal Health. He maintains the immediate danger stays contained.
“We need to be prepared to respond early enough. But for the time being, you can happily walk in the forest, eat chicken and eggs and enjoy your life. The pandemic risk is a possibility. But in terms of probability, it’s still very low,” Torres said.
Rameix-Welti emphasized preparation advantages gained through COVID-19 experience. Should H5 mutate into a human-transmissible form, response systems stand ready.
“The positive point with flu, compared to COVID, is we have specific preventative measures in place. We have vaccine candidates ready and know how to manufacture a vaccine quickly,” she said.
Stockpiles of targeted antiviral medications exist and should prove effective against this avian strain.
The virus continues spreading among wildlife, poultry farms, and mammal populations. Scientists track each mutation, searching for genetic changes that might enable human-to-human transmission.
Written by Alius Noreika
