How does the flu virus work?

Viruses are nasty, yet surprisingly simple organisms. Most human flu viruses have 11 genes at most, compared to the more than 20,000 genes found in humans. 

What makes flu so potentially dangerous is that it’s not very good at making copies of itself, which leads to mutations, or slight changes in its genetic code. Though most mutations don’t amount to anything, some can lead to new versions – or strains – of the flu that could spread more easily or make people sicker once infected.

Dr. Richard Scheuermann, professor of pathology at UT Southwestern Medical Center, said a virus’ ability to mutate partly explains why the seasonal flu vaccine is ineffective against the H1N1 or “swine flu” strain.

“H1N1 is very different from the normal seasonal flu, especially in parts of the virus normally recognized by our protective immune system,” said Dr. Scheuermann, who is also principal investigator of the National Institutes of Health-funded Influenza Research Database. “H1N1 has not mutated in such a way as to make people sicker, but it is important to follow the public health guidelines for who should get vaccinated as the H1N1 vaccine becomes more widely available.”

Visit www.utsouthwestern.org/infectiousdiseases to learn more about UT Southwestern’s clinical services for infectious diseases.

Media Contact: Kristen Holland Shear