Eurosurveillance - Volume 18, Issue 15, 11 April 2013

Novel influenza viruses of the H7N9 subtype have infected 33 and killed nine people in China as of 10 April 2013. Their haemagglutinin (HA) and neuraminidase genes probably originated from Eurasian avian influenza viruses; the remaining genes are closely related to avian H9N2 influenza viruses. Several characteristic amino acid changes in HA and the PB2 RNA polymerase subunit probably facilitate binding to human-type receptors and efficient replication in mammals, respectively, highlighting the pandemic potential of the novel viruses.

In January 2013 in the Netherlands, a man in his 50s from Suriname underwent hemihepatectomy because of a cystic liver mass, assumed to be a cystadenoma. Pathology revealed an echinococcal infection. PCR analysis of cyst material identified Echinococcus vogeli, causing polycystic hydatid disease. This echinococcus species is rarely diagnosed outside South America. The patient received adequate treatment, but this case emphasises the importance of awareness of this infection when treating patients with cystic tumours from endemic areas.

Mortality monitoring systems are important for gauging the effect of influenza and other wide ranging health threats. We present the daily all-cause mortality monitoring system routinely used in Scotland, which differs from others by using two different statistical models for calculating expected mortality. The first model is an extended Serfling model, which captures annual seasonality in mortality using sine and cosine terms, and is frequently seen in other systems. Serfling models fit to summer seasonality well, but not to the winter peak. Thus, during the winter, there are frequent `excesses', higher than expected mortality, making it harder to directly judge if winter mortality is higher than in previous years. The second model, a Generalised Additive Model, resolves this by allowing a more flexible seasonal pattern that includes the winter peak. Thus, excesses under the second model directly indicate if winter mortality is higher than in previous years, useful, for example, in judging if a new strain of seasonal influenza is more likely to produce death than previous ones. As common in all-cause mortality monitoring systems, the Scottish system uses a reporting delay correction: we discuss the difficulties of interpretation when such a correction is used and possible avenues for future work that may address these difficulties. .

Sixty per cent of the Swedish population received the monovalent AS03-adjuvanted pandemic influenza vaccine in the autumn of 2009. We assessed the age-specific effectiveness of this pandemic vaccine against hospitalisation with laboratory-confirmed influenza A(H1N1)pdm09 during the season 2010/11, in the age group from six months to 64 years in Sweden. The screening method was applied to available surveillance data. Our results suggest a prevailing effectiveness of 72% (95% confidence interval (CI): 63-80%) with the highest effectiveness among children, six months to nine years-old (92%, 95%CI: 80-97%). However, there were limitations in data quality and study design due to the lack of systematic recording of administered vaccinations, which underline the importance of preparing for an evaluation when planning for large public health actions. Despite these limitations, we believe the results reflect true, high prevailing vaccine effectiveness. Indeed, there were fewer deaths caused by influenza and the impact of influenza on intensive care units was less severe during the 2010/11 season in Sweden than in countries with lower pandemic vaccination coverage. The association between the pandemic vaccine and narcolepsy has increased the importance of assessing the risks and benefits of the vaccination; studies on the effectiveness and the duration of protection are needed for this. .