Sometimes a new strain of influenza virus emerges to which humans have no natural protection. If the new influenza virus is easily transmitted from person to person, it can result in serious disease affecting people worldwide. This is called an influenza pandemic. Influenza pandemics occurred in 1918, 1957 and 1968. The next influenza pandemic will occur when a new strain of influenza virus emerges that is easily transmitted from person to person.
A pandemic is caused by a new influenza A virus that most people have never been exposed to, so everyone is susceptible. Pandemic strains also often cause more serious disease. Because of this, past flu pandemics have led to high levels of illness, death, social disruption and economic loss.
Seasonal outbreaks of flu are caused by strains of flu virus similar to those of past years. Some people may have built up immunity, and there is also a vaccine for each year's flu season.
Three pandemics occurred in the 20th century, all of which spread around the world within one year of being detected. Of these, the pandemic of 1918-1919 was the most severe, with 50 million or more deaths worldwide.
No one can predict when a pandemic might occur, but many scientists believe it is only a matter of time before the next one arises. Experts from around the world are watching the H5N1 Avian (bird) Flu situation in Africa, Europe and Asia very closely and are preparing for the possibility that the virus may begin to spread more easily and widely from person to person.
Current flu vaccines will not protect against a new pandemic strain of flu virus. Because it takes several months to develop and distribute vaccine for a new strain, a vaccine probably would not be available in the early stages of a pandemic. If a pandemic occurs, it is expected that the U.S. government will work with many partner groups to make recommendations to guide the early use of vaccine. Vaccines that may be effective against H5N1 virus are being developed and tested.
Antiviral medications can be used to treat and/or prevent influenza A viruses. However, flu strains can become resistant to antiviral medications. For example, only one antiviral medication works against the H5N1 Avian Flu virus identified in human patients in Asia in 2004 and 2005. The supply of this antiviral medication is very limited worldwide, and no pharmaceutical company in the United States manufactures it.
Protect yourself against the spread of the flu and other germs and viruses: