Public health experts have warned that controversial experiments on mutant viruses could put human lives in danger by unleashing an accidental pandemic.

Several groups of scientists around the world are creating and altering viruses to understand how natural strains might evolve into more lethal forms that spread easily among humans.

But in a report published yesterday, researchers at Harvard and Yale universities in the U.S. argue that the benefits of the work are outweighed by the risk of pathogenic strains escaping from laboratories and spreading around the world.

They calculate that if ten high-containment labs in the U.S. performed such experiments for ten years, the chance of at least one person becoming infected was nearly 20 per cent. If an infected person left the laboratory, the virus might then spread more widely.

“We are not saying this is going to happen, but when the potential is a pandemic, even a small chance is something you have to weigh very heavily,” said Marc Lipsitch, an epidemiologist at Harvard School of Public Health, who wrote the report with Alison Galvani, an epidemiologist at Yale.

The report threatens to reignite a crisis in science that erupted in 2012 when a U.S. biosecurity panel ruled that two separate studies on mutant bird flu were too dangerous to publish. They described the creation of new mutant strains. One fear was that the recipe for the pathogens might fall into the hands of bioterrorists. Those studies, led by Ron Fouchier at Erasmus medical centre in Rotterdam, and Yoshihiro Kawaoka at the University of Wisconsin-Madison respectively, were eventually published after months of delays. Other researchers have now begun similar experiments.

Both Fouchier and Kawaoka criticised the latest report, published in Plos Medicine, and said their work had full ethical, safety and security approval, with the risks and benefits taken into account.

Last year, the US government, which funds most of the controversial work, revised its guidelines for “dual-use research of concern”, or DURC. Under the new rules, work can be funded if the potential benefits are substantial and the risks considered to be manageable.

But Lipsitch said there was no evidence that the risks and benefits had been weighed up properly. “To my knowledge, no such thing has been done, but funding for these experiments continues,” he said.

Simon Wain-Hobson, a virologist at the Pasteur Institute in Paris, said that scientists working on the controversial virus studies should be less defensive. “There are times when we have to open up and face our critics. Marc is articulating what many of us feel is obvious,” he said. — © Guardian Newspapers Limited, 2014

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