Is H5N1 influenza a doomsday virus, as some would have us believe?

The papers have been full of articles over recent months about a doomsday influenza virus called H5N1 that has been created by scientists. The New York Times (Jan. 7), the Economist and other papers are thundering about looming calamity, and this column was about to do the same. But in a moment of sense I decided to visit my friend and colleague, Vincent Racaniello. Dr. Racaniello is the Higgins professor of microbiology at Columbia, the author of an important virology textbook and host of the podcast “This Week in Virology.”

Flu viruses are made of segments of genetic material surrounded by a protein shell. Many variations of flu virus circulate in birds, pigs, humans and other animals. When different viruses infect the same cell, they may trade genes, creating a new virus to which our unvaccinated immune systems cannot respond quickly, as in the H1N1 pandemic of 2009. (See “The flu is with us again, but maybe not forever,” The Lakeville Journal, Oct. 20, 2011, for details of flu viruses and new ways to defeat them.) Viral genes may also mutate in a less dramatic way, and these mutations can also cause trouble.

The reason for the excitement in the press is that among 571 people hospitalized with an acute H5N1 influenza infection, nearly 60 percent died. The infected people had been in close contact with birds that carried H5N1. H5N1 does not spread easily from one human or mammal to another, so the infection has not spread worldwide in the human population. Now, scientists in three laboratories have selected mutated forms of H5N1 that infect at least one mammal — the ferret.

The bad news is that the mutated virus from one ferret infects others in nearby cages. Most flu viruses affect the upper airways, but the new version of H5N1, which has five mutations that distinguish it from the previous virus, adheres to molecules on the surface of cells found farther down in the lungs of ferrets and humans, accounting for its transmissibility.

Two questions arise from this work. First, should we be scared? Second, should scientists be free to do potentially dangerous experiments? As for being scared, Dr. Racaniello smiled.

“Look, the virus is not nearly as lethal as it sounds,” he said. “Everyone thinks that there have been only 571 cases in Southeast Asia and very high lethality, but those were people who had been hospitalized. There are thousands of people who have been infected and had mild disease or no symptoms at all. We know this because they have antibodies to the virus in their blood. The chances of dying from H5N1 are not even close to 60 percent. Even in seasonal flu, if you are sick enough to be in the hospital, you have a good chance of dying, perhaps 20 percent, but only a fraction of 1 percent of infected people are sick enough to be hospitalized.”

There are other reasons for sober concern rather than panic. The fact that the virus spreads among ferrets does not mean that it will do so among humans. Trials in Southeast Asia show that the drug Tamiflu works against H5N1 and a vaccine is ready for rapid production if the virus evolves to allow human-to-human infection.

Finally, there may soon be new methods to create vaccines and to treat acute viral infections. The H5N1 virus has been followed since the 1990s and thanks to modern DNA sequencing and data analysis, the medical and scientific community will know quickly when it acquires new properties. This is still a serious virus but, according to Dr. Racaniello, everyone, including the editorial writers and reporters of The New York Times, should calm down.

Should scientists be free to do potentially dangerous experiments? The rationale in this case was not evil, but there are several worries. First, a virus that infects humans could escape from the laboratory and second, the information might be considered a source for terrorists. Those risks have to be balanced against the potential utility of the information. The nature of the new mutations has not been made public and both Nature and Science, two prestigious journals, are considering whether to publish the data.

The instinct of scientists is that to know is better than not to know, but some say this work should never have been done. There is no reason that decisions like the one to select a transmissible virus should be left exclusively to scientists, who are morally no wiser than any other group. All major research institutions have institutional review boards that decide whether an experiment on humans is permissible, and they include nonscientists. Perhaps the same should hold true on questions of dangerous experiments, like generating new viruses. The Lakeville Journal’s editorial page welcomes all opinions and discussion, as do I.

Richard Kessin, Ph.D, is Professor of Pathology and Cell Biology at the College of Physicians and Surgeons of Columbia University. He and his wife, Galene, live in Norfolk. He can be contacted at rhk2@columbia.edu.