Severity of the clinical presentation of hepatitis A in five European countries from 1995 to 2014.

Objectives: We analysed hepatitis A (HepA) notifications and hospitalisations in Italy, the Netherlands, Norway, Spain, and Sweden for available periods between 1995 and 2014. We aimed to investigate whether decreasing HepA incidence is associated with increasing age at infection and worsening HepA presentation and to identify groups at risk of severe disease.

Methods: We performed a retrospective cohort study including 36 734 notified and 36 849 hospitalised patients.

Reduced risk of hospitalisation among reported COVID-19 cases infected with the SARS-CoV-2 Omicron BA.1 variant compared with the Delta variant, Norway, December 2021 to January 2022.

We included 39,524 COVID-19 Omicron and 51,481 Delta cases reported in Norway from December 2021 to January 2022. We estimated a 73% reduced risk of hospitalisation (adjusted hazard ratio: 0.27; 95% confidence interval: 0.

Outbreak caused by the SARS-CoV-2 Omicron variant in Norway, November to December 2021.

In late November 2021, an outbreak of Omicron SARS-CoV-2 following a Christmas party with 117 attendees was detected in Oslo, Norway. We observed an attack rate of 74% and most cases developed symptoms. As at 13 December, none have been hospitalised.

Increased risk of hospitalisation and intensive care admission associated with reported cases of SARS-CoV-2 variants B.1.1.7 and B.1.351 in Norway, December 2020 -May 2021.

Introduction: Since their emergence, SARS-CoV-2 variants of concern (VOC) B.1.1.

Occupational risk of COVID-19 in the first versus second epidemic wave in Norway, 2020.

BackgroundThe occupational risk of COVID-19 may be different in the first versus second epidemic wave.AimTo study whether employees in occupations that typically entail close contact with others were at higher risk of SARS-CoV-2 infection and COVID-19-related hospitalisation during the first and second epidemic wave before and after 18 July 2020, in Norway.MethodsWe included individuals in occupations working with patients, children, students, or customers using Standard Classification of Occupations (ISCO-08) codes.

Heavy weather events, water quality and gastroenteritis in Norway.

Climate change will lead to more extreme weather events in Europe. In Norway, little is known about how this will affect drinking water quality and population's health due to waterborne diseases. The aim of our work was to generate new knowledge on the effect of extreme weather conditions and climate change on drinking water and waterborne disease.

The effectiveness of syndromic surveillance for the early detection of waterborne outbreaks: a systematic review.

Background: Waterborne outbreaks are still a risk in high-income countries, and their early detection is crucial to limit their societal consequences. Although syndromic surveillance is widely used for the purpose of detecting outbreaks days earlier than traditional surveillance systems, evidence of the effectiveness of such systems is lacking. Thus, our objective was to conduct a systematic review of the effectiveness of syndromic surveillance to detect waterborne outbreaks.

Exotic dried fruits caused Agbeni outbreak with severe clinical presentation, Norway, December 2018 to March 2019.

We describe an outbreak of Agbeni sequence type (ST)2009 infections in Norway. Between 31 December 2018 and 16 March 2019, 56 cases (33 female and 23 male; median age: 50 years, range: 2-91) were reported, of which 21 were hospitalised. Cases were defined as people living in Norway, with laboratory-confirmed infection with .

COVID-19 cases reported to the Norwegian Institute of Public Health in the first six weeks of the epidemic.

Background: The first case of SARS-CoV-2 infection in Norway was confirmed on 26 February 2020. Following sharpened advice on general infection control measures at the beginning of the outbreak, extensive national control measures were implemented on 12 March, and testing was focused on those with severe illness. We describe the first six weeks of the outbreak in Norway, viewed in light of testing criteria and control measures.

Spatial tick bite exposure and associated risk factors in Scandinavia.

Tick-borne diseases are emerging and re-emerging threats causing public health concerns in Europe and North America. Prevention and control requires understanding of human exposure and behaviour. The aim was to measure exposure to tick bites across Scandinavia, its spatial distribution and the associated risk factors.

Large waterborne outbreak: use of multiple approaches to investigate contamination of the drinking water supply system, Norway, June 2019.

On 6 June 2019, the Norwegian Institute of Public Health was notified of more than 50 cases of gastroenteritis in Askøy. A reservoir in a water supply system was suspected as the source of the outbreak because of the acute onset and geographical distribution of cases. We investigated the outbreak to confirm the source, extent of the outbreak and effect of control measures.

The establishment and first experiences of a crisis advisory service for water supplies in Norway.

Water supply systems, in particular small-scale water supply systems, are vulnerable to adverse events that may jeopardise safe drinking water. The consequences of contamination events or the failure of daily operations may be severe, affecting many people. In Norway, a 24-hour crisis advisory service was established in 2017 to provide advice on national water supplies.

Evaluation of the national surveillance of Legionnaires' disease in Norway, 2008-2017.

Background: In Norway, Legionnaires' disease is reportable upon clinical suspicion to public health authorities and mandatorily notifiable through the Norwegian surveillance system for communicable diseases (MSIS) for both clinicians and laboratories. In the summer of 2017, several European countries reported high notification rates for Legionnaires' disease, which was not observed in Norway. We evaluated MSIS to assess if it meets its objectives of detecting cases and trends in incidence of Legionnaires' disease.

Implementation of multiplex PCR diagnostics for gastrointestinal pathogens linked to increase of notified Shiga toxin-producing Escherichia coli cases in Norway, 2007-2017.

The aim of this study was to investigate implementation of multiplex PCR assays (broad screening PCR) on the distribution and characteristics of notified Shiga toxin-producing Escherichia coli (STEC) cases in Norway, 2007-2017. We described STEC cases notified to the Norwegian Surveillance System for Communicable Diseases (MSIS), 2007-2017 and categorised cases as high-virulent, low-virulent or unclassifiable STEC infections based on guidelines for follow-up of STEC cases. We conducted descriptive analysis and time series analysis allowing for trends and seasonality, and calculated adjusted incidence rate ratios (aIRR) using negative binomial regression for laboratories with and without broad screening PCR.

Travel-associated hepatitis A in Europe, 2009 to 2015.

BackgroundTravel to countries with high or intermediate hepatitis A virus (HAV) endemicity is a risk factor for infection in residents of countries with low HAV endemicity. The objective of this study was to estimate the risk for hepatitis A among European travellers using surveillance and travel denominator data. We retrieved hepatitis A surveillance data from 13 European Union (EU)/ European Economic Area (EEA) countries with comprehensive surveillance systems and travel denominator data from the Statistical Office of the European Union.

Water usage in the Gaza Strip: recommendations from a literature review and consultations with experts.

Water quality in the Gaza Strip has been severely compromised due to increasing salinity, contamination with pollutants, and lack of adequate treatment options. To provide the population of the Gaza Strip with advice on how to mitigate health risks from water we developed recommendations on using water from different sources for different purposes (such as for consumption, hygiene, amenities, and irrigation) based on a literature review and consultation with experts. Specific advice was developed for several vulnerable groups, including infants, children, pregnant or lactating women, and elderly people.

Association between heavy precipitation events and waterborne outbreaks in four Nordic countries, 1992-2012.

We conducted a matched case-control study to examine the association between heavy precipitation events and waterborne outbreaks (WBOs) by linking epidemiological registries and meteorological data between 1992 and 2012 in four Nordic countries. Heavy precipitation events were defined by above average (exceedance) daily rainfall during the preceding weeks using local references. We performed conditional logistic regression using the four previous years as the controls.

National outbreak of Yersinia enterocolitica infections in military and civilian populations associated with consumption of mixed salad, Norway, 2014.

In May 2014, a cluster of Yersinia enterocolitica (YE) O9 infections was reported from a military base in northern Norway. Concurrently, an increase in YE infections in civilians was observed in the Norwegian Surveillance System for Communicable Diseases. We investigated to ascertain the extent of the outbreak and identify the source in order to implement control measures.

Are the current notification criteria for Lyme borreliosis in Norway suitable? Results of an evaluation of Lyme borreliosis surveillance in Norway, 1995-2013.

Background: The approach to surveillance of Lyme borreliosis varies between countries, depending on the purpose of the surveillance system and the notification criteria used, which prevents direct comparison of national data. In Norway, Lyme borreliosis is notifiable to the Surveillance System for Communicable Diseases (MSIS). The current notification criteria include a combination of clinical and laboratory results for borrelia infection (excluding Erythema migrans) but there are indications that these criteria are not followed consistently by clinicians and by laboratories.