Mild flu season softens impact of vaccine delay

Flu peaked later this year for most of country

A milder-than-usual flu season helped lessen the impact of flu vaccine delays across the country, the Centers for Disease Control and Prevention in Atlanta reported. Manufacturing problems with this year’s influenza strain led to delays in the distribution of vaccine and an emphasis on the need to vaccinate high-risk patients and health care workers. The availability of vaccine varied widely across the country, as some hospitals received their usual flu vaccine orders nearly on time and others were told that most of their shipment would arrive in November and December — and that they should expect 10% to 15% less than they ordered.

The CDC had guaranteed an additional 9 million doses of vaccine, which became available in the fall. By January, about 6 million doses remained available.

Typically, hospitals conduct influenza vaccinations in October. Flu activity usually peaks between late December and March. As of late January, flu activity nationwide was below levels from winter 2000. "It certainly was fortuitous that [the activity] came later this year than we saw last year," says Carolyn Buxton Bridges, MD, a medical epidemiologist in the influenza branch of CDC. Even with a milder season, influenza could be a more serious problem in certain parts of the country. It may take a year or more for a full evaluation of the impact of the vaccine delay, she says.

"We know this has been a difficult year for a lot of health departments and hospitals," she says. "We’re still gathering information to be able to gauge how much of a problem it was and what segments had a more difficult time than others."