Questions and Answers About Swine Flu

Andrew Pekosz, an associate professor of molecular microbiology and immunology at Johns Hopkins University's Bloomberg School of Public Health in Baltimore, answers questions from readers about swine flu.

Q Does the swine flu outbreak appear likely to be labeled a pandemic? And if it is labeled a pandemic, how lethal do you expect it to be?

AGiven the number of cases outside of the United States and Mexico, I expect that this epidemic will be officially called a pandemic by WHO declaring a stage 6 pandemic alert sometime soon. We continue to see spread in the human population, which is a concern. We see disease that appears to be similar to what we see with seasonal influenza, so it doesn't appear this virus has a very high virulence or disease-causing potential, which is reassuring. We don't think there is much immunity to this virus strain, so a much larger portion of the population may be susceptible, which is a concern. Overall, I am cautiously optimistic.

Do you feel we have overreacted as a society to the swine flu? Does panic ever get in the way of an appropriate public health response?

If you listen carefully to our public health and government leaders, you'll hear a very consistent message of caution and concern coupled with intense efforts to monitor the number of swine flu cases. These actions match the perceived threat of swine flu at this time. Don't let overload from the various media outlets lead to either complacency or overreaction.

If I have the swine flu, could I have infected those with whom I came in contact the day before symptom onset?

A person infected with influenza can transmit the virus to others for approximately 24 hours before they have symptoms. This is what makes containing influenza cases so difficult.

Further questions? Send them to health@washpost.com.