It’s official: The H1N1 virus—a.k.a. swine flu—is now labeled a pandemic, and it’s the first influenza pandemic since 1968, according to the World Health Organization (WHO). The rapid spread of the virus across North America, Australia, South America, Europe and regions beyond prompted that declaration after 74 countries reported 28,774 cases of swine flu and 144 deaths.

“This declaration reminds the world that flu viruses like H1N1 need to be taken seriously,” said U.S. Department of Health and Human Services Secretary Kathleen Sebelius. “Although we have not seen large numbers of severe cases in this country so far, things could possibly be very different in the fall—especially if things change in the Southern Hemisphere—and we need to start preparing now in order to be ready for a possible H1N1 immunization campaign, starting in late September.”

Researchers are racing to ready a vaccine, but they say October is the earliest it would be available.

Learn more about H1N1 and how you can prevent contracting it on the Centers of Disease Control and Prevention site.