Mumps

Background

Mumps is a disease resulting from infection by the mumps virus. The disease is characterised by swelling of one or both cheeks or sides of the jaw, also known as parotitis, along with:

  • fever
  • headache
  • swollen glands

Mumps infection can also lead to serious complications including:

  • aseptic meningitis
  • encephalitis
  • inflammation of the testes
  • pancreatitis
  • oophoritis
  • permanent deafness

The most effective strategy for preventing the transmission of mumps is vaccination with the measles mumps rubella (MMR) vaccine.

More information on mumps can be found on the NHS inform website.

Guidance

Guidance on mumps: risk in pregnancy, infection in healthcare settings and the MMR vaccine can be found on the Public Health England website.

For all infection prevention and control guidance visit the A-Z ​pathogens section of the National Infection and Prevention Control Manual.

Data and surveillance

Surveillance update for 2018

Mumps was a common childhood disease before the introduction of the MMR vaccine with more than 85% of adults having evidence of previous mumps infection. Following the introduction of the MMR vaccine in 1988, the incidence of mumps substantially decreased. However, since 2004 there has been ongoing widespread increased incidence of mumps throughout the UK with the number of laboratory confirmed cases peaking in 2005. As shown in Figure 1, smaller outbreaks have occurred in 2009, 2012 and 2014 to 2015. Most of the individuals affected were adolescents and young adults and had not had an opportunity to receive two doses of MMR – they had received one or none at all.

Figure 1 is a line chart showing the number of laboratory reports of mumps by year from 2000 to 2018. The figure shows the outbreak which occurred in 2004 and peaked in 2005 with 1887 and 2586 cases, respectively. While the number of cases has decreased since 2005, smaller outbreaks have occurred in 2009, 2012, 2015 and 2017. 280 cases were reported in 2018.

Figure 2 shows that in the last four years, the number of laboratory confirmed mumps cases each year has been variable, ranging from 216 cases in 2016 to 817 in 2015. In 2014 to 2015 a widespread outbreak occurred which mainly affected those in higher education with many cases having evidence of receiving two doses of MMR vaccine.

The observed increase in cases during this period may represent poor initial immune response to the mumps component of the MMR vaccine, waning immunity or a combination of both within fully and partially vaccinated individuals.

Figure 2 is a bar chart showing the number of laboratory reports of mumps by month from 2014 to 2018. The graph shows there was an increase in cases across the end of 2014 and the whole of 2015. An increase in cases was observed at the end of 2017 and continued into early 2018 but the number of cases is decreasing.

In 2018, there were 280 laboratory-confirmed mumps cases, a decrease compared to 2017 in which there were 385 cases reported. Mumps activity was high at the beginning of the year and was associated with an outbreak in NHS Lothian which began in the student population in the latter part of 2017 and then spread into the wider community. The monthly number of cases decreased since January and stabilised to levels similar to what is reported in previous years in which no outbreaks are occurring.

Age distribution of cases

Figure 3 shows that the majority of mumps cases in the past four years have been in those aged between 17 to 34 years, consistent with the age groups which are likely to be under immunised with a mumps containing vaccine.

Figure 3 presents the age breakdown of the laboratory reports for mumps by year from 2014 to 2018. The graph shows that every year the majority of mumps cases are in adolescents and young adults.

In 2018 in Figure 4,the incidence of mumps was highest in those in the 17 to 20 year old age group at 43.6 cases per 100,000, followed by the 21 to 24 year old age group (16.3 cases per 100,000) and the 25 to 34 age group (10.6 cases per 100,000).

Figure 4 presents the number of laboratory reports of mumps by age group in 2018 as a bar chart and the incidence rate per 100,000 as a line graph.  Figure 4 shows that incidence per 100,000 is highest in those aged 17-20 years at 43.6 per 100,000.

Laboratory confirmed cases by NHS boards

Figure 5 shows that the incidence of mumps varied greatly between NHS Boards in 2018 with the highest incidence in NHS Lothian (17.8 cases per 100,000) where there was an increase of mumps cases in the student population and the community. This was followed by NHS Tayside (6.0 cases per 100,000) and NHS Borders (4.35 cases per 100,000).

Figure 5 presents the number of laboratory reports of mumps by NHS board in 2018 as a bar chart and the incidence rate per 100,000 as a line graph. There is variation between NHS boards with the highest rate in NHS Lothian at 17.8 per 100,000.

Limitations

There are limitations caused by a reliance on laboratory reports as this will represent a considerable underestimate of community circulation of mumps as many cases may be undiagnosed or based on clinical confirmation only.  It should also be noted that differences in sampling and testing practices may account for variation across the NHS boards.

Vaccination

Vaccine uptake statistics are available on the Information Services Division (ISD) website.