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Source: http://www.cidrap.umn.edu/news-pers...in-scotland-support-flu-vaccine-effectiveness
Studies from Spain, Scotland support flu vaccine effectiveness
Filed Under:
Influenza Vaccines
Robert Roos | News Editor | CIDRAP News
|
Feb 26, 2015
A study in Valencia, Spain, suggests that this year's influenza vaccine has been modestly effective in preventing flu-related hospital admissions, in contrast to findings of low vaccine effectiveness this year in the United States and several other countries.
In addition, a study covering nine past flu seasons in Scotland indicates that flu vaccines provided about 60% protection for nonelderly adults but little protection for the elderly. Both studies were published today in Eurosurveillance.
In January US researchers reported a preliminary estimate that this year's vaccine was only 23% effective overall, and recent vaccine effectiveness (VE) estimates from Canada and the United Kingdom were even lower. Officials have cited a mismatch between circulating and vaccine H3N2 strains as a major factor in the weak performance.
[h=3]VE in Spain: 33%[/h] The Spanish researchers used a test-negative case-control design to examine vaccine effectiveness (VE) in preventing flu-related admissions at 10 hospitals in Valencia. They enrolled 1,136 patients with flu-like illness, of whom 210 tested positive for flu. Of those, 110 (52%) had been vaccinated. Of those who tested negative, 64% had been vaccinated.
The overall adjusted VE was estimated at 33% (95% confidence interval [CI], 6%-53%); in those 65 and older, VE was 40% (CI, 13%-59%). "The probability of influenza-related admission in vaccinated individuals was 13% (10?15%) compared with 22% (18?27%) in those unvaccinated," the report says.
"Our estimate suggests that the 2014/15 influenza vaccine was moderately effective in preventing hospital admissions related to influenza in a season in which most influenza A(H3N2) viruses were different from the component in the 2014/15 influenza vaccine," it concludes.
[h=3]9-season study: VE varies by age[/h] In Scotland, researchers used flu test results from clinics and hospitals to examine flu VE from the 2000-01 through the 2008-09 seasons, also using a test-negative case-control design.
They found that vaccination was associated with a 57% (95% CI, 31%-73%) reduction in the risk of confirmed flu overall, but age made a big difference. VE was 60% (95% CI, 22%-79%) for patients younger than 65 and at risk for serious flu complications, but only 19% (95% CI, −104%-68%) for those 65 years and older, which made it not statistically significant.
"Vaccination was associated with substantial, sustained reductions in laboratory-confirmed influenza in the general population and younger patients in clinical at-risk groups," the authors wrote.
See also:
Feb 26 Eurosurveillance report on Spanish study
Feb 26 Eursurveillance report on Scottish study
Studies from Spain, Scotland support flu vaccine effectiveness
Filed Under:
Influenza Vaccines
Robert Roos | News Editor | CIDRAP News
|
Feb 26, 2015
A study in Valencia, Spain, suggests that this year's influenza vaccine has been modestly effective in preventing flu-related hospital admissions, in contrast to findings of low vaccine effectiveness this year in the United States and several other countries.
In addition, a study covering nine past flu seasons in Scotland indicates that flu vaccines provided about 60% protection for nonelderly adults but little protection for the elderly. Both studies were published today in Eurosurveillance.
In January US researchers reported a preliminary estimate that this year's vaccine was only 23% effective overall, and recent vaccine effectiveness (VE) estimates from Canada and the United Kingdom were even lower. Officials have cited a mismatch between circulating and vaccine H3N2 strains as a major factor in the weak performance.
[h=3]VE in Spain: 33%[/h] The Spanish researchers used a test-negative case-control design to examine vaccine effectiveness (VE) in preventing flu-related admissions at 10 hospitals in Valencia. They enrolled 1,136 patients with flu-like illness, of whom 210 tested positive for flu. Of those, 110 (52%) had been vaccinated. Of those who tested negative, 64% had been vaccinated.
The overall adjusted VE was estimated at 33% (95% confidence interval [CI], 6%-53%); in those 65 and older, VE was 40% (CI, 13%-59%). "The probability of influenza-related admission in vaccinated individuals was 13% (10?15%) compared with 22% (18?27%) in those unvaccinated," the report says.
"Our estimate suggests that the 2014/15 influenza vaccine was moderately effective in preventing hospital admissions related to influenza in a season in which most influenza A(H3N2) viruses were different from the component in the 2014/15 influenza vaccine," it concludes.
[h=3]9-season study: VE varies by age[/h] In Scotland, researchers used flu test results from clinics and hospitals to examine flu VE from the 2000-01 through the 2008-09 seasons, also using a test-negative case-control design.
They found that vaccination was associated with a 57% (95% CI, 31%-73%) reduction in the risk of confirmed flu overall, but age made a big difference. VE was 60% (95% CI, 22%-79%) for patients younger than 65 and at risk for serious flu complications, but only 19% (95% CI, −104%-68%) for those 65 years and older, which made it not statistically significant.
"Vaccination was associated with substantial, sustained reductions in laboratory-confirmed influenza in the general population and younger patients in clinical at-risk groups," the authors wrote.
See also:
Feb 26 Eurosurveillance report on Spanish study
Feb 26 Eursurveillance report on Scottish study