NEW YORK (AP) \u2014 As the U.S. flu season winds down, health officials say the flu vaccine didn\u2019t work very well, with one of its worst effectiveness rates in more than a decade.<\/p>\n
A new strain that dominated the early winter was not well matched to the vaccine, leading to an intense early onslaught of flu.<\/p>\n
The Centers for Disease Control and Prevention on Friday posted data<\/a> that showed a continued decline in doctor\u2019s office and hospital visits for flu symptoms through last week. The number of states reporting high flu activity dropped to 16, many of them in a belt stretching from Colorado to Virginia.<\/p>\n \u201cThe winter respiratory virus season is slowly coming to a close, and we\u2019re all very grateful for that,\u201d said Dr. William Schaffner, a Vanderbilt University vaccine expert.<\/p>\n This season\u2019s vaccines were around 25% to 30% effective in preventing adults from getting sick enough from the flu that they had to go to a doctor\u2019s office, clinic or hospital, according to a CDC report<\/a> this week. Children who were vaccinated were about 40% less likely to get treatment at a doctor\u2019s office or hospital.<\/p>\n Officials generally are pleased if a flu vaccine is 40% to 60% effective. Judging from past CDC research<\/a>, this season saw one of the lowest effectiveness rates in the last two decades.<\/p>\n Flu infections surged in late December<\/a> and were especially intense in some parts of the country. New York City health officials called it the most intense season in 20 years.<\/p>\n Relatively low flu vaccination rates did not help, but experts also blamed the new flu strain that was causing most infections.<\/p>\n The new strain belonged to a category of flu virus, called A H3N2. This new version, subclade K, seemed to spread more easily \u2014 though it did not necessarily cause more severe illness.<\/p>\n The vaccine available for this season was built to address a different version of H3N2, and the new strain\u2019s explosion is a likely explanation for why the vaccine was less effective, Schaffner said.<\/p>\n CDC scientists estimate there have been at least 27 million illnesses, 350,000 hospitalizations and 22,000 deaths from flu so far this season. At the same point last year, the estimates were at least 40 million illnesses, 520,000 hospitalizations, but about the same number of deaths.<\/p>\n At least 101 children have died so far this season. For those whose vaccination status is known, about 85% were not fully vaccinated against flu.<\/p>\n The flu vaccine may not protect everyone from getting sick, but it can prevent people from becoming severely ill and dying. That\u2019s why getting a flu shot remains worthwhile, Schaffner said.<\/p>\n