Get Your Flu Shot, Folks!

[Ms. Toad]

196. Yes. Some studies have found even lower.

2010 vaccine 0% - 60% improvement

Mar 1, 2013 (CIDRAP News) – Experts are puzzled by a new study in which influenza vaccination seemed to provide little or no protection against flu in the 2010-11 season—and in which the only participants who seemed to benefit from the vaccine were those who hadn't been vaccinated the season before.

The investigators recruited 328 households in Michigan before the flu season started and followed them through the season. Overall, they found that the infection risk was nearly the same in vaccinated and unvaccinated participants, indicating no significant vaccine-induced protection, according to their report in Clinical Infectious Diseases. That contrasted sharply with several other observational studies that found the vaccine to yield about 60% protection during the same season.

http://www.cidrap.umn.edu/news-perspective/2013/03/study-getting-flu-shot-2-years-row-may-lower-protection

He also cautioned that the meta-analyses focus on nursing homes, which are very different from hospitals, where patient turnover is higher and there are often people in the facility who aren't HCWs. Even with 100% vaccination rates in employees, the roughly 60% protection offered by the vaccine creates a gap in which workers can still get sick and spread the virus to patients, he said.

http://www.cidrap.umn.edu/news-perspective/2013/09/analysis-finds-limited-evidence-hcw-flu-vaccination

A total of 2,319 children and adults were enrolled in the study from Dec 2, 2013, to Jan 23, 2014, according to a separate MMWR article today. Of those, 784 tested positive for flu by polymerase chain reaction. Twenty-nine percent of those who tested positive had been vaccinated, versus 50% of those who tested negative. That translates into a VE of 61% (95% confidence interval [CI], 52%-68%).

http://www.cidrap.umn.edu/news-perspective/2014/02/cdc-flu-vaccine-61-effective-too-few-adults-get-it