The daily updated Dutch national database on COVID-19 epidemiology, vaccination and sewage surveillance

The Dutch national open database on COVID-19 has been incrementally expanded since its start on 30 April 2020 and now includes datasets on symptoms, tests performed, individual-level positive cases and deaths, cases and deaths among vulnerable populations, settings of transmission, hospital and ICU admissions, SARS-CoV-2 variants, viral loads in sewage, vaccinations and the effective reproduction number. This data is collected by municipal health services, laboratories, hospitals, sewage treatment plants, vaccination providers and citizens and is cleaned, analysed and published, mostly daily, by the National Institute for Public Health and the Environment (RIVM) in the Netherlands, using automated scripts. Because these datasets cover the key aspects of the pandemic and are available at detailed geographical level, they are essential to gain a thorough understanding of the past and current COVID-19 epidemiology in the Netherlands. Future purposes of these datasets include country-level comparative analysis on the effect of non-pharmaceutical interventions against COVID-19 in different contexts, such as different cultural values or levels of socio-economic disparity, and studies on COVID-19 and weather factors.

Exceptionally low rotavirus incidence in the Netherlands in 2013/14 in the absence of rotavirus vaccination

An unexpected drop in rotavirus (RV) detections was observed in the Netherlands in 2014, without RV vaccination. The estimated decrease in RV detections and gastroenteritis consultations in under five year-olds, in January-April 2014, compared to the same months in previous years, was 72% and 36%, respectively. The low birth rate, mild winter, high RV incidence in the previous year and the introduction of RV vaccination in neighbouring countries may have contributed to this decrease.

Persistent and transient hepatitis B virus (HBV) infections in children born to HBV-infected mothers despite active and passive vaccination

Combined passive and active immunization for newborns very effectively prevents perinatal hepatitis B virus (HBV) infections. In the Netherlands, babies born to hepatitis B surface antigen (HBsAg)-positive women receive passive immunization with hepatitis B and at least three active HBsAg vaccinations. Serological testing for the presence of HBV markers was offered for all infants born to HBsAg-positive mothers between January 2003 and July 2007, after completion of their vaccination schedule. About 75% of the infants (n = 1743) completed their HB-vaccination schedule and participated in the serologic evaluation. Twelve of them (0.7%) were found to be HBV infected. Furthermore, we identified three older children with high levels of anti-HBc, anti-HBs and anti-HBe, while they were HBsAg and HBV DNA negative. This serologic profile is evidence for a resolved HBV infection. In the group of older children (1.5-5 years of age, n = 728), about half of the HBV-infected children (3 of 7) had already cleared their infection at the time of sampling. For a proper evaluation of the efficacy of a new intervention programme to prevent vertical HBV transmission, it is also important to analyse the HBV markers in serum collected when the children are older than 1.5 years. In a programmatic setting, all children born to HBV-infected mothers should be tested not only for the level of anti-HBs but also for the absence of HBsAg, because 2 of the 12 HBV-infected children (17%) had a high level of anti-HBs.

Ongoing mumps outbreak in a student population with high vaccination coverage, Netherlands, 2010

Since December 2009, mumps incidence has increased in the Netherlands. As of 20 April 2010, 172 cases have been notified on the basis of laboratory confirmation or linkage to a laboratory-confirmed case. Of these, 112 were students, the majority of whom had been vaccinated (81%). Although outbreaks in vaccinated populations have been described before, risk factors for exposure and susceptibility, and dose-dependent vaccine effectiveness in a student population of this nature are relatively unknown.

Epidemiology and control of influenza A(H1N1)v in the Netherlands: the first 115 cases

Introductions of the new influenza A(H1N1) variant virus in the Netherlands led to enhanced surveillance and infection control. By 24 June 2009, 115 cases were reported, of whom 44% were indigenously acquired. Severity of disease is similar to reports elsewhere. Our point estimate of the effective reproductive number (Re) for the initial phase of the influenza A(H1N1)v epidemic in the Netherlands was below one. Given that the Re estimate is based on a small number of indigenous cases and a limited time period, it needs to be interpreted cautiously.

Measles outbreak in an anthroposophic community in The Hague, The Netherlands, June-July 2008

An ongoing outbreak of measles linked to anthroposophic communities in The Hague, The Netherlands has been identified since mid-June 2008. Thirty-four cases have been reported until 25 July. In addition, two cases have been reported in other cities (Leiderdorp and Utrecht). Both are epidemiologically linked to the cluster in The Hague.

Mumps in a community with low vaccination coverage in the Netherlands

The incidence of mumps in the Netherlands has increased since August 2007. Until mid May 2008, 89 individuals were found positive for mumps virus infection by laboratory testing at the Centre for Infectious Diseases Control (CIb) of the Dutch National Institute for Public Health and the Environment (RIVM), compared to less than 10 cases per year between 2005 and 2007. Mumps is not a notifiable disease in the Netherlands and surveillance is mainly based on monitoring laboratory test requests and their results offered by the CIb and other laboratories. As only a minority of cases is offered laboratory testing, however, the extent of the current mumps outbreak is unknown.

Mumps outbreak ongoing since October 2007 in the Republic of Moldova

The Republic of Moldova is experiencing a nationwide mumps outbreak, with a total of 19,550 notified cases as of 23 March 2008. The outbreak started in October 2007, with 105 cases notified in that month compared to an average number of 24 cases per month notified between January and September 2007. Between 1 October and 31 December 2007, 1,524 cases were notified.

[Vaccination against pneumococci and hepatitis B in the Dutch National Immunisation Programme]

All infants in the Netherlands, which are born after March 2006, receive additional vaccinations at the age of 2, 3, 4 and 11 months to protect them against pneumococcal infections. During the same visit to a consultation bureau, the children also receive a combination vaccine against diphtheria, pertussis, tetanus, poliomyelitis and Haemophilus influenzae (DTPa-IPV-Hib). Children of which at least one parent was born in a country where hepatitis B occurs relatively often are also vaccinated in the Netherlands against hepatitis B. This currently pertains to about 15% of all newborns. These children now receive a new combination vaccine in which a hepatitis B component has been added to the DTPa-IPV-Hib components. They will receive this combination vaccine 4 times. This combination vaccine is given during the same visit as the pneumococcal vaccination. Although pneumococcal vaccination may have a somewhat negative effect on the immune response to hepatitis B, it is expected that the new 4-fold vaccination schedule will induce good and long-lasting protection against hepatitis B in the vast majority of the children. About 700 children are born out of mothers infected with hepatitis B each year in the Netherlands. In the new vaccination schedule, they now receive 5 active vaccinations against hepatitis B and are examined serologically on an individual basis in order to detect breakthrough infections. This will also generate greater insight into the efficacy of the different vaccination schemes and intervention programmes to prevent vertical transmission of the virus.

Hepatitis B incidence among South Asian children in England and Wales: implications for immunisation policy

The incidence of acute hepatitis B virus (HBV) infection is higher among South Asian than among non-South Asian UK residents, and infections in South Asians occur more often during childhood. The UK's immunisation policy should be changed to protect ethnic minority children against HBV infection.