Webvaccine effectiveness varied across outcomes, age groups, immunocompromised status, and virus type. Flu vaccines reduced the risk of. Webwith febrile illness as the clinical end point, the attack rate was 2. 2% in the vaccine group and 7. 1% in the placebo group (69% efficacy). Webthis season's influenza vaccines have been 42% effective so far, according to a new interim estimate from the centers for disease control and prevention,. Webthese vaccine effectiveness (ve) studies help regularly assess the value of flu vaccination as a public health intervention. The results of vaccine effectiveness.
