Content on this page was developed during the 2009-2010 H1N1 pandemic and has not been updated.

• The H1N1 virus that caused that pandemic is now a regular human flu virus and continues to circulate seasonally worldwide.
• The English language content on this website is being archived for historic and reference purposes only.
• For current, updated information on seasonal flu, including information about H1N1, see the CDC Seasonal Flu website.

The human swine flu outbreak continues to grow in the United States and internationally. Today, CDC reports additional cases of confirmed swine influenza and a number of hospitalizations of swine flu patients. Internationally, the situation is more serious too, with additional countries reporting confirmed cases of swine flu. In response to the intensifying outbreak, the World Health Organization raised the worldwide pandemic alert level to Phase 4. A Phase 4 alert is characterized by confirmed person-to-person spread of a new influenza virus able to cause “community-level” outbreaks.” The increase in the pandemic alert phase indicates that the likelihood of a pandemic has increased.

CDC has activated its emergency operations center to coordinate the agency’s emergency response. CDC ’s goals are to reduce transmission and illness severity, and provide information to help health care providers, public health officials and the public address the challenges posed by this swine influenza virus. Yesterday, CDC issued a travel warning recommending that people avoid non-essential travel to Mexico. CDC continues to issue interim guidance daily on the website and through health alert network notices. CDC’s Division of the Strategic National Stockpile (SNS) is releasing one-quarter of its antiviral drugs, personal protective equipment, and respiratory protection devices to help states respond to the outbreak. The swine influenza A (H1N1) virus is susceptible to the prescription antiviral drugs oseltamivir and zanamivir. This is a rapidly evolving situation and CDC will provide updated guidance and new information as it becomes available.

What You Can Do to Stay Healthy

There are everyday actions people can take to stay healthy.

• Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
• Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.
• Avoid touching your eyes, nose or mouth. Germs spread that way.

Try to avoid close contact with sick people.

• Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people.
• If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.

Past Daily Updates

• April 27, 2009
• April 26, 2009
• April 25, 2009
• April 24, 2009
• April 23, 2009