Improving preparedness to respond to cross-border hepatitis A outbreaks in the European Union/European Economic Area: towards comparable sequencing of hepatitis A virus.

IntroductionSequence-based typing of hepatitis A virus (HAV) is important for outbreak detection, investigation and surveillance. In 2013, sequencing was central to resolving a large European Union (EU)-wide outbreak related to frozen berries. However, as the sequenced HAV genome regions were only partly comparable between countries, results were not always conclusive.AimThe objective was to gather information on HAV surveillance and sequencing in EU/European Economic Area (EEA) countries to find ways to harmonise their procedures, for improvement of cross-border outbreak responses.MethodsIn 2014, the European Centre for Disease Prevention and Control (ECDC) conducted a survey on HAV surveillance practices in EU/EEA countries. The survey enquired whether a referral system for confirming primary diagnostics of hepatitis A existed as well as a central collection/storage of hepatitis A cases' samples for typing. Questions on HAV sequencing procedures were also asked. Based on the results, an expert consultation proposed harmonised procedures for cross-border outbreak response, in particular regarding sequencing. In 2016, a follow-up survey assessed uptake of suggested methods.ResultsOf 31 EU/EEA countries, 23 (2014) and 27 (2016) participated. Numbers of countries with central collection and storage of HAV positive samples and of those performing sequencing increased from 12 to 15 and 12 to 14 respectively in 2016, with all countries typing an overlapping fragment of 218 nt. However, variation existed in the sequenced genomic regions and their lengths.ConclusionsWhile HAV sequences in EU/EEA countries are comparable for surveillance, collaboration in sharing and comparing these can be further strengthened.

Influenza vaccine effectiveness in adults 65 years and older, Denmark, 2015/16 - a rapid epidemiological and virological assessment.

In Denmark, both influenza A(H1N1)pdm09 and influenza B co-circulated in the 2015/16 season. We estimated the vaccine effectiveness (VE) of the trivalent influenza vaccine in patients 65 years and older using the test-negative case-control design. The adjusted VE against influenza A(H1N1)pdm09 was 35.0% (95% confidence interval (CI): 11.1-52.4) and against influenza B 4.1% (95% CI: -22.0 to 24.7). The majority of influenza A(H1N1)pdm09 circulating in 2015/16 belonged to the new genetic subgroup subclade 6B.1.

Incidence and cost of rotavirus hospitalizations in Denmark.

In anticipation of licensure and introduction of rotavirus vaccine into the western market, we used modeling of national hospital registry data to determine the incidence and direct medical costs of annual rotavirus-associated admissions over >11 years in Denmark. Diarrhea-associated hospitalizations coded as nonspecified viral or presumed infectious have demonstrated a marked winter peak similar to that of rotavirus-associated hospitalizations, which suggests that the registered rotavirus-coded admissions are grossly underestimated. We therefore obtained more realistic estimates by 2 different models, which indicated 2.4 and 2.5 (for children <5 years of age) and 4.9 and 5.3 (for children <2 years of age) rotavirus-associated admissions per 1,000 children per year, respectively. These admissions amount to associated direct medical costs of US $1.7-1.8 million per year. Using 2 simple models to analyze readily available hospital discharge data resulted in more consistent and reliable estimates.

Hospitalizations and deaths from diarrhea and rotavirus among children <5 years of age in the United States, 1993-2003.

Recently a new rotavirus vaccine was licensed in the United States and recommended for universal immunization of American children. The impact of the vaccine on a decrease in hospitalizations will take several years to assess and will be based on the availability of good baseline data on the disease. We used the largest US hospital discharge database available, the Healthcare Cost and Utilization Project (HCUP), to study national rates, trends, and risk factors for diarrhea- and rotavirus-associated hospitalizations and deaths among children <5 years of age, to establish a baseline against which vaccine implementation can be measured. Rotavirus remained the most important cause of pediatric diarrhea throughout the study period (1993-2003). When the data were extrapolated to the US population, rotavirus was estimated to be the cause of approximately 60,000 hospitalizations and 37 deaths annually. Black infants had a significantly higher risk of being hospitalized with and dying from rotavirus disease early in life, compared with white infants (risk ratio [RR] for hospitalization by 12 months of age was 2.4, with a 95% confidence interval [CI] of 1.2-4.7; RR for death was 2.0, with a 95% CI of 1.7-2.5). Such racial differences in age and risk of rotavirus-associated hospitalization and death highlight the importance of timely and early rotavirus immunization of minority children. The HCUP database serves as a sensitive and robust data source for monitoring the impact of a rotavirus-immunization program in the United States.