A couple of years ago, the news media were inundated with stories of the most recent spread of the deadly avian flu infection. The certainty of facing a worldwide epidemic was looming, and I recall attending a conference session in which the presenter ran a computer simulation showing how the entire population of a small country could be infected in less than 6 weeks.

Today, one of the biggest health concerns worldwide continues to be the threat of pandemic outbreak, particularly human infections with the H5N1 virus, the cause of avian influenza A. Since 2003, the World Health Organization has been tracking the number of laboratory-confirmed human cases of avian influenza A, which so far has totaled 408, including 13 so far this year. Now, it appears that the fight against H5N1 and other influenza viruses has taken a progressive leap forward.

The H5 type hemagglutinin (HA) has been studied intensely as scientists seek a strategy for preventing or slowing down the spread of infection of host cells. This week, a research team from The Dana—Farber Cancer Institute (Boston, MA) and the Burnham Institute for Medical Research (La Jolla, CA) announced they had identified human monoclonal antibodies (mAb) that bind to the stem of the H5 HA. By binding to the stem, the antibodies prevent the conformational change in the protein that allows the viral RNA to enter the host cell. This process can neutralize a broad range of influenza A virus subtypes, including different types of the avian flu and seasonal flu viruses. When the method was tested in mice, results showed that the mAb protected against H5N1 exposure.

Although producing therapeutic antibodies is more expensive than existing influenza drugs, researchers point out that the antibodies take less time to manufacture (compared with six to nine months for vaccines using conventional methods) and they can be used with antiviral therapies to slow down the rate of infection until a vaccine is available.