Science and the Swine Flu

You’ve likely heard news reports this week about the swine flu virus outbreak in Mexico. The swine flu or swine influenza produces regular outbreaks of respiratory disease in pigs and is caused by influenza type A viruses. Transmission of swine flu viruses between people has been reported in the past, but was limited to three people. Today, the World Health Organization (WHO) raised its pandemic alert to "phase 5", which means that people in at least two countries in one WHO region are spreading the disease [1]. This was done following an increase to "phase 4" several days ago because the virus was already widespread in differnet locations, with confirmations in Mexico, the United States, Spain and Scotland.

While the Centers for Disease Control and Prevention (CDC) has determined that the swine flu is contagious and is spreading from human to human [2], the WHO has indicated that most people infected with swine flu make a full recovery without the need for medical attention or antiviral drugs [3].

Lifetime Immunity From the Flu

Scientists report in the current issue of the journal Nature Structural and Molecular Biology the isolation of a group of high-affinity antibodies that are potent inhibitors of a wide range of influenza viruses, including the H5N1 avian flu, the 1918 Spanish flu and some seasonal strains [1]. The antibodies may someday be used to create a vaccine that provides lifetime immunity from the flu.

Seasonal flu hospitalizes an average of 226,000 people in the U.S. annually, killing 36,000 every year [2]. Influenza A viruses have been associated with an increasing number of deaths; from 1990 — 1999, the greatest mean number of flu deaths were associated with influenza A (H3N2) viruses [3]. Each season, between one quarter- and a half-million people die of influenza worldwide [4].