Flu vaccine offers slightly less protection to high-risk patients, study says
A new study in Vaccine led by a group from the US Centers for Disease Control and Prevention estimates a multi-season flu vaccine effectiveness (VE) of 41% among patients with high-risk medical conditions, compared with 48% for those without.
The study compared flu VE rates among more than 25,000 patients at outpatient facilities in Michigan, Pennsylvania, Texas, Washington state, and Wisconsin across four recent flu seasons (December of 2012 through April of 2016). High-risk status was noted by diagnosis with one or more diseases, including asthma, diabetes, liver diseases, and immunosuppressive diseases.
Overall, 6,032 (62%) of 9,643 patients with high-risk conditions had received current season influenza vaccination, versus 6,224 (40%) of 15,726 patients without high-risk conditions.
Among patients with high-risk conditions, VE against any influenza was 41% (95% confidence interval [CI], 35% to 47%) for all ages, 51% (95% CI, 39%-61%) for children, and 38% (95% CI, 30%-45%) for adults. Among patients without high-risk conditions, VEs were 48% (95% CI, 43%-52%) for all ages and 52% (95% CI, 44%-58%) and 44% (95% CI, 38%-50%), respectively, for children and adults.
"While VE against any influenza was statistically lower among patients with high risk conditions (41%) compared to those without high-risk conditions (48%), this analysis did not suggest large deficits in vaccine-induced protection among people with high-risk conditions," the authors concluded.
"In addition, the differences in age strata were not significantly different by high-risk status, suggesting that protection among patients with high-risk conditions was not substantially lower than that observed among patients without high-risk conditions."
Nov 9 Vaccine study
Low-path H5N2 avian flu found on 4 more Minnesota turkey farms
Increased surveillance in the wake of two low-pathogenic H5N2 avian flu outbreaks at commercial turkey farms in Minnesota has led to the detection of the virus at four more farms in the two affected counties, according to a Nov 8 notification from the World Organization for Animal Health (OIE).
The first outbreak was reported in late October and was the result of stepped-up surveillance for avian flu viruses following devastating outbreaks in 2015 involving a highly pathogenic H5N2 virus, mainly in Minnesota and other Midwestern states.
Of the four new low-pathogenic H5N2 detections, three are in Stearns County in central Minnesota and the other involves a similar facility in neighboring Kandiyohi County. The viruses were detected between Oct 23 and Nov 1. Among the four locations, the farms house 178,000 birds and will be depopulated through controlled marketing. Other response steps include controlling the movement of birds, quarantine, and disinfection of the affected farms.
Partial genetic sequencing suggests that the new detections are related to the virus at the first farm affected this year. Full sequencing of the virus from the first farm show that all gene segments are consistent with a North American wild bird low-pathogenic H5N2 lineage.
Nov 8 OIE report on low path H5N2 in Minnesota