Flu vaccine may also protect against pneumonia
Most children and adults hospitalized for flu-related pneumonia haven't had a flu shot, the researchers said.
"Influenza vaccine can substantially reduce the risk of hospitalizations for influenza pneumonia, a serious complication of influenza infections," said lead researcher Dr. Carlos Grijalva, an associate professor of health policy at Vanderbilt University School of Medicine in Nashville.
"We estimate that approximately 57 percent of hospitalizations due to influenza pneumonia could be prevented by influenza vaccination," he said.
For the study, Grijalva and his colleagues collected data on nearly 2,800 patients hospitalized for pneumonia in four U.S. hospitals from January 2010 through June 2012.
Approximately 6 percent of these patients had flu-related pneumonia, while other patients were hospitalized for pneumonia that was not caused by influenza, Grijalva explained.
"We compared the history of influenza vaccination between these patients. We found that influenza vaccination was associated with a reduced risk of influenza pneumonia that required hospitalization," he said.
In the United States, annual flu epidemics send more than 200,000 people to the hospital and kill as many as 49,000, according to the U.S. Centers for Disease Control and Prevention. ■