Eurosurveillance - Volume 20, Issue 5, 05 February 2015

In 2014/15 the United Kingdom experienced circulation of influenza A(H3N2) with impact in the elderly. Mid-season vaccine effectiveness (VE) shows an adjusted VE of 3.4% (95% CI: ?44.8 to 35.5) against primary care consultation with laboratory-confirmed influenza and ?2.3% (95% CI: ?56.2 to 33.0) for A(H3N2). The low VE reflects mismatch between circulating viruses and the 2014/15 northern hemisphere A(H3N2) vaccine strain. Early use of antivirals for prophylaxis and treatment of vulnerable populations remains important.

Virus strains in the seasonal influenza vaccine for the 2014/15 northern hemisphere season remained unchanged from those in 2013/14. During spring 2014, drifted influenza A(H3N2) viruses, subgroup 3C.3a, were detected in Finland; another subgroup, 3C.2a, emerged in the 2014/15 season and has predominated. We monitored antibody responses against vaccine and epidemic strains (2013/14 and 2014/15) among Finnish healthcare workers after influenza vaccination with the 2013/14 vaccine. The data suggest reduced cross-protection towards both subgroups of drifted A(H3N2) viruses.

The 2014/15 influenza season in Canada has been characterised to date by early and intense activity dominated by influenza A(H3N2). A total of 99.0% (593/599) hospitalisations for laboratory-confirmed influenza with a known influenza virus type enrolled in sentinel hospitals of the Serious Outcomes Surveillance Network of the Canadian Immunization Research Network were due to influenza A. Of the 216 with a known subtype, influenza A(H3N2) accounted for 99.1% (n=214). Interim unmatched vaccine effectiveness (VE) estimates adjusted for age and presence of one or more medical comorbidities were determined by test-negative case-control design to be ?16.8% (90% confidence interval (CI): ?48.9 to 8.3) overall and ?22.0% (90% CI: ?66.5 to 10.7) for laboratory-confirmed influenza A(H3N2). Among adults?aged under?65 years, the overall VE was 10.8% (90% CI: ?50.2 to 47.0) while in adults?aged 65 years or older, the overall VE was ?25.4% (90% CI: ?65.0 to 4.6). .

A simple genotyping method was developed and validated for all known Chlamydia psittaci reference genotypes. C. psittaci is currently divided into nine genotypes (A-F, E/B, M56 and WC), all more or less associated with the preferred avian host. This method targeting variable domain 4 of the ompA gene has a lowest detection limit of 1 to 10 copies per PCR and was applied to 69 human samples collected in nine hospitals in the Netherlands from September 2008 until the end of October 2013. Genotype A was the most prevalent genotype. In addition, genotypes B, C, a new genotype, and C. abortus were found. A C. caviae infection was detected as a result of extension of this surveillance study to the national level. The sensitivity of this method compared with our real-time diagnostic PCR was 0.98 (66/67 typable samples). Specificity was 1.0 based on 33 commonly encountered bacterial and yeast species and 20 human respiratory samples. This typing method could help monitor C. psittaci infections in humans and provides insight into the relationships between notified human 'psittacosis' cases and the probable avian and other animal sources. When needed, a result can be obtained within 24 hours. .