What is the real story behind the H1N1 outbreak?
An influenza pandemic occurs roughly three times a century. The most severe recently documented influenza pandemic was 1918. About one percent of those who became ill died. Since 1997, CDC and others had been tracking a novel influenza, H5N1, sometimes called bird flu. The world was overdue for an influenza pandemic. H5N1 was and continues to be very deadly, with about 60% of people who develop the illness die. When H1N1 was first recognized in Mexico in 2009, no one could predict whether it was going to be a severe pandemic. Early indications were that healthy young adults died, like in 1918.
The United States had a choice: gamble H1N1 would not kill in high numbers, or work as fast as possible to develop a vaccine and make it available to as many Americans as possible. In fact, there was no choice—the vaccine had to be made and distributed. Doing so, along with other protective steps, prevented millions of cases of H1N1 influenza and thousands of hospitalizations and deaths. H1N1 did kill, including infants, young adults and pregnant women. The virus continues to circulate as does the more deadly but less contagious H5N1. CDC is constantly on alert for new, deadly influenza viruses and other airborne diseases.
CDC Foundation