Eurosurveillance - Volume 20, Issue 4, 29 January 2015

The influenza season 2014/15 started in Europe in week 50 2014 with influenza A(H3N2) viruses predominating. The majority of the A(H3N2) viruses characterised antigenically and/or genetically differ from the northern hemisphere vaccine component which may result in reduced vaccine effectiveness for the season. We therefore anticipate that this season may be more severe than the 2013/14 season. Treating influenza with antivirals in addition to prevention with vaccination will be important.

The 2014/15 influenza season to date in Canada has been characterised by predominant influenza A(H3N2) activity. Canada's Sentinel Physician Surveillance Network (SPSN) assessed interim vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza A(H3N2) infection in January 2015 using a test-negative case-control design. Of 861 participants, 410 (48%) were test-positive cases (35% vaccinated) and 451 (52%) were test-negative controls (33% vaccinated). Among test-positive cases, the majority (391; 95%) were diagnosed with influenza A, and of those with available subtype information, almost all influenza A viruses (379/381; 99%) were A(H3N2). Among 226 (60%) A(H3N2) viruses that were sequenced, 205 (91%) clustered with phylogenetic clade 3C.2a, considered genetically and antigenically distinct from the 2014/15 A/Texas/50/2012(H3N2)-like clade 3C.1 vaccine reference strain, and typically bearing 10 to 11 amino acid differences from the vaccine at key antigenic sites of the haemagglutinin protein. Consistent with substantial vaccine mismatch, little or no vaccine protection was observed overall, with adjusted VE against medically attended influenza A(H3N2) infection of ?8% (95% CI: ?50 to 23%). Given these findings, other adjunct protective measures should be considered to minimise morbidity and mortality, particularly among high-risk individuals. Virus and/or host factors influencing this reduced vaccine protection warrant further in-depth investigation. .

A multistate outbreak of hepatitis A virus (HAV) among European travellers returning from Egypt occurred between November 2012 and April 2013. A total of 14 European Union (EU)-European Free Trade Association (EFTA) countries reported 107 cases. Twenty-one cases from six countries were affected by strains of sub-genotype IB harbouring identical RNA sequences, suggesting a common source outbreak. An international outbreak investigation team interviewed a number of cases with a trawling questionnaire to generate hypotheses on potential exposures. Some of these exposures were further tested in a case-control study based on a more specific questionnaire. Both trawling and case-control questionnaires aimed to collect cases' vaccination details as well as epidemiological information. Most cases participating in either questionnaire (35/43) had been staying in all-inclusive hotels located along the Red Sea. The case-control study found cases associated with exposure to strawberries or mango (multivariable analysis p value: 0.04). None of the 43 cases interviewed in any of the two questionnaires had been vaccinated. The most common reasons for non-vaccination was unawareness that HAV vaccination was recommended (23/43, 53%) and perceiving low infection risk in all-inclusive luxury resorts (19/43, 44%). Vaccination had not been recommended to five of the six cases who sought travel medical advice before travelling. Public health authorities should strongly reinforce measures to remind travellers, travel agencies and healthcare providers of the importance of vaccination before visiting HAV-endemic areas, including Egypt. .

Leptospirosis in humans is a mandatory notifiable disease in Denmark. To identify changing trends in human leptospirosis in Denmark, we analysed data from the passive laboratory surveillance and clinical notifications from a 32-year period (1980-2012). In that period, 584 cases of leptospirosis were laboratory-diagnosed, an average annual incidence rate of 0.34 cases/100,000 population (range: 0.07-1.1/100,000 population). Seventy per cent of patients were male. Overall, Patoc was the predominant serogroup diagnosed (32%) but over time, the Leptospira serogroup distribution has changed. In recent years Icterohaemorrhagiae and Sejroe have been diagnosed most frequently, in contrast to Patoc and Sejroe in earlier years. Notification data for 170 cases showed that work-related exposures were reported in 48% of infections, with fish farming (44%) and farming (22%) as the most frequently mentioned professions. Other common exposures were related to travel (13%), recreation (8%) and sewage (7%). Geomapping of cases showed a geographical clustering for some exposures. Future preventive measures could include raising awareness among clinicians about the risks and prevention of exposure in specific groups (fish farmers, farmers and travellers) to reduce leptospirosis in Denmark. .