Preliminary estimates show the flu vaccine is offering moderate protection against severe illness and hospitalizations this season, according to a new CDC report.
The vaccine was between 41% and 44% effective at preventing hospitalizations among adults this season. For children and adolescents, these figures ranged from 52% to 61%. The flu shot's effectiveness at preventing outpatient visits ranged from 59% to 67% among children and 33% to 49% among adults.
"Flu vaccines have worked, substantially reducing the risk of flu-related medical visits and hospitalizations across all age groups, with some estimates higher than have been previously observed, even during well-matched seasons," the agency said Feb. 29.
Historically, flu shot efficacy rates have ranged from a high of 60% in the 2010-11 season to a low of 10% for the 2004-05 season, when the CDC started tracking this data.
This season's preliminary estimates come from four flu surveillance systems covering patients across 22 states, according to the CDC.
View the full report here.