European interim flu vaccine tracking finds moderate effectiveness
An early look at this season's flu vaccine in Europe shows that protection against influenza A has ranged between 32% and 43% across all patients seen at clinics and hospitals and was 59% in groups targeted for vaccination, according to findings from six European studies published today in Eurosurveillance.
Europe's flu season began late in most countries, with little influenza B activity. Both influenza A strains are circulating in some countries, with others reporting dominant 2009 H1N1 or H3N2.
Against the 2009 H1N1 strain, vaccine effectiveness (VE) ranged from 40% to 71%, and three of the studies found lower protection levels in older adults, ranging from 0% to 37%. And, against H3N2—the most challenging strain—three of the four studies of primary care clinics found no protection across all age-groups, though the authors said few H3N2 cases mean VE estimates are less precise than for 2009 H1N1.
When compared with recent interim reports from other countries, the results from three of the studies were similar to estimates from Canada and the United States.
In a UK study that included the inhaled quadrivalent live attenuated influenza vaccine (LAIV), VE against influenza A in children was high, at 80%. And that findings suggest that a 2009 H1N1 vaccine strain switch from A/Bolivia to A/Slovenia after the 2016-17 season may have helped improved performance against circulating strains; however, the authors cautioned that the sample size was very small.
Genetic diversity of flu viruses in the flu season under way in Europe didn't seem to affect VE against 2009 H1N1 in most groups. So far, all H1N1 viruses characterized in Europe are antigenically similar to the vaccine virus, though lower protection in seniors in the Danish primary care clinic study needs further study but might be explained by small sample size.
"End-of-season VE and antigenic studies will provide insight into age- and study-specific variation in VE estimates," the authors wrote.
Feb 21 Eurosurveill study
Jan 24 CIDRAP News scan "Study: Flu vaccine offers 68% protection in Canada, 72% against H1N1"
Feb 14 CIDRAP News story "Early US flu vaccine analysis finds moderate protection"
Three new MERS cases recorded in Saudi Arabia
Saudi Arabia's Ministry of Health (MOH) reported three new MERS-CoV case today in an epidemiologic week 8 notification.
Two male patients from Wadi ad-Dawasir have been diagnosed as having MERS-CoV (Middle East respiratory syndrome coronavirus). The patients are a 26-year-old man who is hospitalized and a 35-year-old man who is in home isolation. Neither patient had camel contact, a known risk factor, and the MOH said it was investigating the source of the patients' infections.
A total of 47 MERS cases have been recorded in Wadi ad-Dawasir since the first of the year, in an apparent hospital outbreak.
A third case was recorded in a 36-year-old man from Buraydah. The man is hospitalized and did not have camel contact. The source of his infection is listed as "primary," meaning it is unlikely he contracted the virus from another person.
Saudi Arabia has now reported 73 MERS-CoV cases this year.
Feb 21 MOH report
Study: Mumps immune response drops off 7 to 17 years after vaccination
In an effort to understand why young adults in the Unites States still contract mumps—despite high vaccination rates—researchers from the Mayo Clinic and Food and Drug Administration followed a cohort of 98 measles, mumps, and rubella (MMR) vaccine recipients for 17 years to measure immune responses to measles and mumps. The results are published in Vaccine.
Each subject was a school-age child from Olmsted County, Minnesota, and received both doses of MMR. The subjects were subjected to two blood draws, one at 7 years after the second MMR dose, and one 10 years later, or 17 years after the second dose.
Mumps immunoglobulin G antibodies (Abs) dropped significantly between the two blood draws.
"The median titer at the first blood draw was 74.8, with an interquartile range of 35.1–170.2. The median titer at the second blood draw (which was between 7.6 and 14.2 years after the first blood draw) was 69.8, with an interquartile range of 25.1–146.2," the authors wrote.
The subjects did not show a significant loss of neutralizing Ab levels to mumps, however. About 42% of the subjects also experienced a more than 20% decrease in measles neutralizing Ab titer.
The authors said their study suggests significant waning in mumps protection in the first 7 to 17 years after vaccination.
Feb 20 Vaccine study