Flu shot doing a poor job of protecting elderly

Car­los Maisonet, 73, reacts as Dr. Eva Berrios-Colon, a pro­fes­sor at Touro Col­lege of Phar­macy, injects him with flu vac­cine dur­ing a visit to the fac­ulty prac­tice cen­ter at Brook­lyn Hos­pi­tal in New York. Health offi­cials said Thurs­day this season’s flu shot was only 9 per­cent effec­tive in pro­tect­ing seniors against the most com­mon and dan­ger­ous flu bug. Flu vac­cine tends to pro­tect younger peo­ple bet­ter than older ones and is never 100 per­cent effec­tive. But experts say the pre­lim­i­nary results are dis­ap­point­ing and high­light the need for a bet­ter vac­cine. (Asso­ci­ated Press | Bebeto Matthews)

MIKE STOBBE

AP Med­ical Writer

ATLANTA — It turns out this year’s flu shot is doing a star­tlingly dis­mal job of pro­tect­ing senior cit­i­zens, the most vul­ner­a­ble age group.

The vac­cine is prov­ing only 9 per­cent effec­tive in peo­ple 65 and older against the harsh strain of the flu that is pre­dom­i­nant this sea­son, the Cen­ters for Dis­ease Con­trol and Pre­ven­tion said Thursday.

Health offi­cials are baf­fled as to why this is so. But the find­ings help explain why so many older peo­ple have been hos­pi­tal­ized with the flu this year.

Despite the find­ings, the CDC stood by its rec­om­men­da­tion that every­one over 6 months get flu shots, the elderly included, because some pro­tec­tion is bet­ter than none, and because those who are vac­ci­nated and still get sick may suf­fer less severe symptoms.

“Year in and year out, the vac­cine is the best pro­tec­tion we have,” said CDC flu expert Dr. Joseph Bresee.

Over­all, across the age groups stud­ied, the vaccine’s effec­tive­ness was found to be a mod­er­ate 56 per­cent, which means those who got a shot have a 56 per­cent lower chance of wind­ing up at the doc­tor with the flu. That is some­what worse than what has been seen in other years.

For those 65 and older, the vac­cine was only 27 per­cent effec­tive against the three strains it is designed to pro­tect against, the worst level in about a decade. It did a par­tic­u­larly poor job against the tough strain that is caus­ing more than three-quarters of the ill­nesses this year.

It is well known that flu vac­cine tends to pro­tect younger peo­ple bet­ter than older ones. Elderly peo­ple have weaker immune sys­tems that don’t respond as well to flu shots, and they are more vul­ner­a­ble to the ill­ness and its com­pli­ca­tions, includ­ing pneumonia.

But health offi­cials said they don’t know why this year’s vac­cine did so poorly in that age group.

One the­ory, as yet unproven, is that older people’s immune sys­tems were accus­tomed to strains from the last two years and had more trou­ble switch­ing gears to han­dle this year’s dif­fer­ent, harsh strain.

The pre­lim­i­nary data for senior cit­i­zens is less than defin­i­tive. It is based on fewer than 300 peo­ple scat­tered among five states.

But it will no doubt sur­prise many peo­ple that the effec­tive­ness is that low, said Michael Oster­holm, a Uni­ver­sity of Min­nesota infectious-disease expert who has tried to draw atten­tion to the need for a more effec­tive flu vaccine.

Among infec­tious dis­eases, flu is con­sid­ered one of the nation’s lead­ing killers. On aver­age, about 24,000 Amer­i­cans die each flu sea­son, accord­ing to the CDC.

This flu sea­son started in early Decem­ber, a month ear­lier than usual, and peaked by the end of year. Hos­pi­tal­iza­tion rates for peo­ple 65 and older have been some of the high­est in a decade, at 146 per 100,000 people.

Flu viruses tend to mutate more quickly than oth­ers, so a new vac­cine is for­mu­lated each year to tar­get the strains expected to be the major threats. CDC offi­cials have said that in for­mu­lat­ing this year’s vac­cine, sci­en­tists accu­rately antic­i­pated the strains that are cir­cu­lat­ing this season.

Because of the guess­work involved, sci­en­tists tend to set a lower bar for flu vac­cine. While child­hood vac­cines against dis­eases like measles are expected to be 90 or 95 per­cent effec­tive, a flu vac­cine that’s 60 to 70 per­cent effec­tive in the U.S. is con­sid­ered pretty good. By that stan­dard, this year’s vac­cine is OK.

For senior cit­i­zens, a flu vac­cine is con­sid­ered pretty good if it’s in the 30 to 40 per­cent range, said Dr. Arnold Monto, a Uni­ver­sity of Michi­gan flu expert.

A high-dose ver­sion of the flu shot was recently made avail­able for those 65 and older, but the new study was too small to show whether that has made a difference.

The CDC esti­mates are based on about 2,700 peo­ple who got sick in Decem­ber and Jan­u­ary. The researchers traced back to see who had got­ten shots and who hadn’t. An ear­lier, smaller study put the vaccine’s over­all effec­tive­ness at 62 per­cent, but other fac­tors that might have influ­enced that fig­ure weren’t taken into account.

The CDC’s Bre­see said there is a dan­ger in pro­vid­ing pre­lim­i­nary results because it may result in peo­ple doubt­ing — or skip­ping — flu shots. But the fig­ures were released to warn older peo­ple who got shots that they may still get sick and shouldn’t ignore any seri­ous flu-like symp­toms, he said.

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