CDC stresses need for flu shot every year
■ The agency disagrees with some health experts saying healthy people who got the vaccine last year might not need it this season.
Although this year's seasonal influenza vaccine will be identical to the one administered in the 2010-11 season, physicians still should provide the vaccine to patients who are 6 months and older, says the Centers for Disease Control and Prevention.
The recommendation is in response to comments by some health experts that young, healthy people who received the 2010-11 flu immunization might not need it this year. They say that such patients already could have sufficient immunity to the three widely circulating influenza viruses included in the vaccine.
The CDC disagrees vehemently with that position.
"We know that, over time, immunity wanes. For someone to be fully protected against influenza, they have to be vaccinated each and every flu season," said CDC spokesman Tom Skinner. "While the [seasonal influenza] vaccine is not changing, you still have to get the vaccine to be fully protected."
The 2011-12 seasonal flu vaccine will contain the pandemic 2009 influenza A(H1N1)-like virus, an A/Perth/16/2009 (H3N2)-like virus and a B/Brisbane/60/2008-like virus. These are the same viruses that were included in the 2010-11 immunization.
Nashville, Tenn., infectious diseases expert William Schaffner, MD, said it is unusual for influenza strains not to mutate from one year to the next. He estimated that it occurs about once every 12 years.
He said the benefit of having the same strains is that vaccine manufacturers already have experience growing the viruses, which means immunizations should be available to physicians early in the season.
Manufacturers expect to produce more than 160 million doses of flu vaccine this year, Skinner said. About the same amount was manufactured in the 2010-11 season, when an estimated 42% of Americans (about 129 million) were immunized against the flu, he said.
In the 2010-11 season, there were 311 confirmed influenza-associated deaths from Oct. 3, 2010, to May 21, 2011, according to a report in the June 3 issue of the CDC's Morbidity and Mortality Weekly Report. Of those deaths, 105 occurred in children younger than age 18 (link).
The CDC said that during the H1N1 pandemic there were 348 reported pediatric deaths between April 15, 2009, and Oct. 2, 2010.
"The bottom line is if a person is to be fully protected [against the flu] every year, they have to get vaccinated every year," Skinner said.