This year's flu vaccine only 36% effective

Second worst level of protection in a decade.

Posted: Feb 15, 2018 4:18 PM

NEW YORK (AP) — The flu vaccine is doing a poor job protecting older Americans and others against the bug that’s causing most illnesses.

Preliminary figures released Thursday suggest the vaccine is 36 percent effective overall in preventing flu illness severe enough to send a patient to the doctor’s office.

There’s only been one other time in the last decade when the flu vaccine did a worse job.

Most illnesses this winter have been caused by a nasty kind of flu called Type A H3N2. The vaccine was only 25 percent effective against that type.

This kind of virus tends to cause more suffering and have been responsible for the worst recent flu seasons. But experts have wondered whether low vaccine effectiveness is another reason for the surprisingly severe season hitting the United States this winter.

Based on these numbers, the answer is yes.

Figures for the 2017-18 season are preliminary.

“The fact that the vaccine doesn’t work as well as we would like is clearly a contributing factor,” said Dr. William Schaffner, a Vanderbilt University vaccine expert.

The estimates were published by the Centers for Disease Control and Prevention.

The numbers are a snapshot taken in the middle of a frantic flu season. They are based on relatively small numbers of people and they are considered preliminary. Numbers may change as the season continues and more patients are added to the study.

And experts say it’s still worth getting a flu shot. It still provides some protection, it can lessen the illness’s severity, keep people out of the hospital, and save lives. There are as many as 56,000 deaths connected to the flu during a bad year.

“Any type of vaccine is better than none,” said Scott Hensley, a University of Pennsylvania microbiologist who has led studies that raised critical questions about the vaccine.

The effectiveness estimates come from the tracking of about 4,600 children and adult patients in five states. To make the effectiveness calculations, researchers tracked who got the flu, and who among them had been vaccinated.

The vaccine provided good protection — 67 percent effective — against another common kind of flu virus, Type A H1N1, which has not been seen much this winter. And it was 42 percent effective against Type B flu viruses.

The vaccine worked relatively well in young children, but it performed worse in older people, including seniors who are most vulnerable. Against H3N2, the vaccine was 51 percent effective in children ages 6 months to 8 years. In every other age group, the numbers were low, falling in a range that made them essentially ineffective in preventing flu, statistically speaking.

That includes people 65 and older, a group that tends to suffer the highest hospitalization and death rates during H3N2 seasons. If the preliminary numbers hold, it will mean that in five of the last eight flu seasons, vaccine was essentially ineffective in seniors.

It points to a need for better flu vaccines, said Dr. Anne Schuchat, the CDC’s acting director.

“The vaccines that we have today are not the ones that we’d like to have in 10 years,” she said.

Scientists think part of the reason for that has to do with when people are born and what kind of flu viruses they’re first exposed to in life. Most seniors were first exposed to H1N1 viruses and their bodies seem to handle them better, but H3N2 viruses — which didn’t spread broadly in the United States until the late 1960s — seem to be harder for their bodies to deal with.

But some researchers say part of the problem is tied to how 85 percent of the nation’s flu vaccine doses are made. Manufacturers grow flu viruses in chicken eggs. But the viruses can mutate in the eggs, and researchers are finding vaccine from the egg-grown viruses is not a good match to the H3N2 flu bugs in people.

Some research suggests that newer vaccines, using newer production methods, seem to work better against recently circulating H3N2 strains, but not enough people in the effectiveness study got those kinds of shots to compare performance.

Minnesota Coronavirus Cases

Data is updated nightly.

Cases: 895229

Reported Deaths: 9462
CountyCasesDeaths
Hennepin1749772017
Ramsey722701040
Dakota66032572
Anoka62513568
Washington39357355
Stearns32821275
St. Louis28761399
Wright25354211
Scott25329181
Olmsted21750127
Sherburne18478126
Carver1629166
Clay11923103
Blue Earth1126366
Rice11234138
Crow Wing11003122
Chisago974676
Kandiyohi9660106
Otter Tail9611126
Benton8815124
Beltrami801794
Goodhue786596
Douglas7689100
Itasca752796
Mower721349
Winona702756
McLeod694483
Isanti681383
Steele669431
Morrison663479
Becker620873
Polk591684
Freeborn550846
Carlton529474
Nobles521654
Lyon518761
Mille Lacs516573
Nicollet510960
Pine500641
Cass491252
Todd483642
Brown465057
Le Sueur445933
Meeker422357
Martin378143
Wabasha366010
Waseca365132
Dodge351511
Hubbard349848
Roseau307931
Fillmore299115
Wadena298239
Redwood277845
Houston266817
Renville264151
Faribault253032
Pennington247529
Sibley246917
Kanabec241536
Cottonwood225032
Chippewa216342
Aitkin215850
Pope203210
Watonwan194920
Yellow Medicine185423
Rock174728
Swift169322
Koochiching168123
Stevens164511
Jackson159216
Clearwater155720
Marshall151122
Murray150911
Pipestone148329
Lake129824
Lac qui Parle120025
Wilkin119416
Mahnomen104714
Norman10389
Grant9719
Big Stone9365
Lincoln8705
Kittson71523
Red Lake70710
Traverse5996
Unassigned572124
Lake of the Woods5235
Cook3020

Iowa Coronavirus Cases

Data is updated nightly.

Cases: 516453

Reported Deaths: 7289
CountyCasesDeaths
Polk80319799
Linn32142424
Scott26637292
Black Hawk21974378
Woodbury20490258
Johnson19778105
Dubuque18515241
Pottawattamie15890213
Dallas15320113
Story1380258
Warren8450104
Cerro Gordo7964123
Clinton7725114
Webster7326122
Des Moines7098105
Marshall669093
Muscatine6645117
Wapello6441144
Jasper619591
Sioux610177
Lee5908105
Marion557897
Buena Vista502149
Plymouth488388
Henry418655
Benton404859
Jones404862
Bremer395372
Washington391463
Boone389739
Carroll367755
Mahaska365365
Crawford353747
Dickinson314655
Jackson307747
Buchanan305741
Clay295536
Delaware294654
Kossuth289077
Fayette286353
Hardin284353
Tama279777
Page272533
Wright266149
Cedar265527
Hamilton259857
Winneshiek258143
Floyd255449
Clayton244459
Poweshiek237243
Madison234525
Harrison234379
Cass233466
Butler232744
Iowa229634
Jefferson223043
Mills220930
Winnebago215938
Hancock214639
Cherokee211347
Lyon206142
Appanoose205357
Allamakee203955
Calhoun196919
Shelby196442
Union191141
Humboldt185130
Grundy183637
Franklin183029
Mitchell182043
Chickasaw178922
Emmet178246
Louisa176953
Sac171026
Guthrie168137
Montgomery161745
Clarke160829
Keokuk150839
Palo Alto150532
Howard146824
Monroe142739
Ida130141
Greene127517
Davis124625
Lucas124426
Monona122939
Worth12139
Pocahontas120724
Adair114337
Osceola104818
Decatur101913
Taylor98514
Fremont95913
Van Buren93222
Wayne84525
Ringgold76729
Audubon74917
Adams5748
Unassigned480
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