Short Communication
Mumps resurgence in Denmark

https://doi.org/10.1016/j.jcv.2014.08.013Get rights and content

Highlights

  • The parotitisvirus detection rate has increased almost 10 times during the past 10 years.

  • The age distribution has shifted from children to young adults.

  • Most cases are unvaccinated or have only received one dose of MMR vaccine.

  • The increase in parotitisvirus cases is due mainly to the existence of cohorts with low MMR vaccine coverage.

Abstract

Background

The past decade has witnessed a resurgence of parotitisvirus (mumps) in several countries where seemingly good mumps control otherwise had been achieved through vaccination. Recently detection of mumps has increased in Denmark.

Objectives

To describe the age-specific changes and time trends of parotitisvirus detection in Denmark over a 10 year period.

Study design

: Retrospective cohort study based on national laboratory data for parotitisvirus typing surveillance and national epidemiology data for mumps reporting.

Results

The parotitisvirus detection rate has increased almost 10 times during the past 10 years from an incidence <0.1 per 100,000 in 2003 to 0.96 per 100,000 in 2013. The age distribution has shifted from children to young adults, and most cases are unvaccinated (54%) or vaccinated once (41%). The increase is due mainly to the existence of cohorts with low MMR vaccine coverage.

Conclusion

Analysis of mumps surveillance data from Denmark documents that the incidence of mumps is increasing, and that the resurgence of parotitisvirus is primarily occurring among young Danish adults. Almost half of the infected clinical mumps cases had received the first dose of MMR.

Section snippets

Background

The past decade has witnessed a resurgence of mumps in several countries where seemingly good mumps control had been achieved through vaccination [1]. By 2010, 118 countries had introduced mumps vaccine, usually in two-dose schedules with measles–mumps–rubella (MMR) vaccine [2]. The year of introduction of one- and two-dose schedules and age groups targeted by immunization and catch-up programs have varied substantially between countries, and each country presents its own epidemiological

Study design

Retrospective cohort study using national laboratory and epidemiology data.

All laboratory confirmed mumps cases available at the central national laboratory at Statens Serum Institut (SSI), Section for Virus Surveillance and Research (parotitisvirus detection by PCR in either throat swap, serum or urine samples) were linked to the national parotitis epidemiology database using the unique social security number. This enabled us to investigate the epidemiological profile and immunization status

Mumps epidemiology in Denmark 1994–2013

Mumps has been individually notifiable since 1994, and 390 cases were reported from 1994 to 2013; the yearly number and incidence are shown in Fig. 1. The lowest incidence was observed in 2002 at 0.4 per 100,000 (95% CI: 0.4–1.1) while in 2013, the incidence had increased to 0.96 per 100,000 (95% CI: 0.8–1.2). Males constitute 59% of cases for the whole period and 56% in 2013 (Table 1). Following an initial decline, mumps case numbers have increased; in 2013 we recorded the highest number in

Discussion

In spite of the insufficient vaccine uptake, the vaccine did initially appear to control the infection: by 2001–2003 only a few cases of mumps were reported per year, with almost half acquired abroad. Since then, however, the yearly number of cases has increased and most are acquired in Denmark.

The age distribution has changed markedly over time, and in recent years young adults have represented the main burden of disease in Denmark, as has been the case elsewhere [1], [6], [7], [8]. Of note is

Funding

None.

Competing interests

None.

Ethical approval

Not needed.

References (17)

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