The flu season in California appears to have peaked without a major outbreak despite the fact that thousands of doses of the flu vaccine remain unused.
Health officials had feared that the flu season would be harsher than normal because of a nationwide shortage of flu vaccine. Although the shortage initially led to long lines at drug stores and clinics distributing the vaccine, California ended up by December with a surplus of flu shots and few takers.
Based on reports from hospitals, health clinics and doctors' offices, the state health department said California had seen only sporadic cases of influenza during the flu season, which usually begins in late December and lasts through March.
By contrast, other parts of the country have seen much more severe outbreaks of the flu.
According to the U.S. Centers for Disease Control and Prevention, 27 states in the Midwest, Northeast and Southwest have reported "widespread" incidents of the flu, including Michigan, Nevada, New York, Texas, Virginia and Washington.
In some places, schools have been temporarily closed because the flu bug swept through.
Only two states -- Alabama and California -- have reported "sporadic" instances of the flu, according to the CDC. And experts are puzzled as to why.
"If I knew the answer to that, I'd get the Nobel Prize," said Dr. Jonathan Fielding, Los Angeles County's public health director. "Some years, we've had it stronger than other places."
Officials say flu activity is largely dictated by the movement of those who are infected.
"The flu comes and goes like weather patterns," said Robert Schechter, co-chairman of the California Department of Health Services. "A storm front may start in one area and pass to another. There are some common patterns, but it's hard to predict where it's going to hit."
Perhaps the most significant element of California's flu season was the discovery in Santa Clara County of a new strain of the influenza that experts believe may be prevalent in the next year.
Named A/California, the new strain is in the same family as A/Fujian, which is this year's most common and potent strain. Although the new strain has not resulted in any significant outbreaks, health officials are warning that it could produce flu cases through the end of March.
"There's no reason to think the new strain is any more or less dramatic than other flu strains circulating in the community," Schechter said.
