Research and analysis

Laboratory confirmed cases of measles, mumps and rubella in England: January to March 2024

Published 26 September 2024

Applies to England

Background

Measles, mumps and rubella are notifiable diseases; healthcare professionals are legally required to inform their local health protection team (HPT) of any suspected case. National enhanced surveillance including oral fluid (OF) testing of all suspected cases is provided through the Virus Reference Department (VRD) at Colindale to support and monitor progress towards World Health Organization (WHO) measles and rubella elimination targets (1).

Two WHO indicators are of prime importance for measuring the performance of national measles and rubella surveillance systems. These are:

  1. The rate of laboratory investigations (at least 80% of suspected cases).
  2. The annual rate of discarded cases (at least 2 per 100,000 population).

In order to achieve these targets, the focus of the UK Health Security Agency (UKHSA) is on ensuring that all suspected cases are appropriately tested. Immunoglobulin M (IgM) serology testing and oral fluid testing are the only tests considered adequate by WHO for confirming or discarding a suspected measles or rubella case. Recent infection is confirmed by measuring the presence of IgM antibodies or detecting viral RNA (by PCR) in these samples.

Samples that have been confirmed positive for measles or rubella in a proficient laboratory (this includes local laboratories as well as the National Reference Laboratory), are included in this report. Samples that are referred to, or tested at, the National Reference Laborartory are further sequenced and entered on the WHO global Measles Nucleotide Surveillance (MeaNS) or the Rubella Nucleotide Surveillance (RubeNS) system, respectively, which are hosted at the National Reference Laboratory. Genotyping and further characterisation of measles and rubella is used to support investigation of transmission pathways and sources of infection.

Data presented here is for the first quarter of 2024 (January to March). Analyses are executed using the onset date of a rash or, more broadly, symptoms.

Historical annual and quarterly measles, mumps and rubella epidemiological data is available from 2013 onwards:

The results from all samples tested at Colindale are reported on our laboratory information system MOLIS. The results are then reported back to the respective general practitioner (GP) and local HPT.

Overview

Table 1. Total suspected cases of measles, mumps and rubella reported to HPTs with breakdown of: a) proportion tested by Oral Fluid (OF); b) other samples received from notified cases; c) cases confirmed at the Virus Reference Department (VRD), Colindale; d) cases confirmed at regional, local NHS hospital and private laboratories; e) discard rate (measles and rubella only): weeks 1 to 14 of 2024

Notified as Number of suspected cases* Number (%) tested by OF** Other samples received by VRD Number of samples IgM positive or viral detection in VRD Number local confirmed Discard rate based on negative tests per 100,000 population (all samples)***
Measles 7,273 3,312 (45.5%) 431 608 279 11.07
Mumps 2,082 1,061 (51.0%) 99 38 22
Rubella 88 35 (39.8%) 9 0 0 0.15

*This represents all cases reported to HPTs in England; that is: possible, probable, confirmed and discarded cases on HPZone.

**The target set by WHO is 80% for measles and rubella only.

***The annual discard rate target set by WHO is 2 cases per 100,000 population. We present quarterly rates here with an equivalent target of 0.5 per 100,000 population. The discard rate is based on VRD testing only because local negative tests are not routinely reported to UKHSA. Therefore, this is likely to be an underestimation of the true discard rate.

Measles

In the period between January and March 2024, 887 laboratory confirmed cases of measles were reported in England, a four-fold increase compared to the previous quarter (n=212) (2) (Figure 1).

During the first quarter of 2024, the number of confirmed cases exceeded the total number reported during the whole of 2023 (n=362). A summary of the 2023 data is published here (3).

The increase in cases this quarter was initially driven by an outbreak in Birmingham and the West Midlands. Subsequently, there was a rise in cases in London and small clusters in other regions across England, see details of the outbreak here (4).

The majority, 62.2% (552/887), of cases were in children aged 10 years and younger. 3.4% (30/887) of cases were previously vaccinated with one dose of the MMR vaccine and 4.4% (39/887) with at least two doses. Of the 887 cases reported this quarter, only 54 (6.1%) were classified as imported or import-related, the remaining cases represent community-level transmission in England. Regional and age-level breakdowns have been published here.

Two laboratory confirmed cases were reported in Northern Ireland and 2 laboratory confirmed cases were reported in Wales in the first quarter of 2024. In Scotland, there were six laboratory confirmed measles cases reported in the first quarter of 2024. Of these cases, five were thought to have been imported and related to international travel and one case was acquired in the UK.

Figure 1. Laboratory confirmed cases of measles by month of onset of rash or symptoms reported, London and England: January 2012 to March 2024

A rapid increase in measles cases in quarter 4 of 2023 led to the declaration of a national standard incident response in England. Since then, the UKHSA have published regular updates on the UKHSA data dashboard and the measles epidemiology webpage.

One acute measles-related death occurred this quarter in a young person who was also known to have other medical conditions (5). More information on measles-related deaths can be found here.

Across the WHO European Region there has been an increase in measles infections, with cases reported in 46 (87%) countries between March 2023 and Febuary 2024. The vast majority of cases were reported by Kazakhstan (n=31,718), Azerbaijan (n=26,765) and the Russian Federation (n=16,438) (6). WHO Europe has warned that a resurgence of measles is now an imminent threat, particularly due to the fall in vaccination rates during the COVID-19 pandemic (7).

All suspected cases of measles and rubella should be reported promptly to HPTs, a risk assessment conducted, and an OF kit sent for confirmatory testing even if local diagnostic testing is underway (1). This quarter, an OF sample was returned for only 46% of all suspected measles cases reported in England, well below the WHO target of 80% (Table 1).

Mumps

In England, there were 60 laboratory confirmed mumps infections in the period January to March 2024, nearly double the case count in the last quarter (n=37) (2).

Seventeen of the 60 cases (28.3%) this quarter were in children below the age of 15 years. Of these, 17.6% (3/17) were vaccinated with one dose of MMR, and 47.1% (8/17) had received at least two doses. Of the 43 cases in those aged 15 years and older, 4.7% (2/42) were vaccinated with one dose of MMR and 20.9% (9/43) had received at least two doses of MMR. The remaining cases had no vaccine recorded.

Figure 2. Laboratory confirmed cases of mumps by quarter, England: January 2012 to March 2024

Rubella

This quarter, there were no laboratory confirmed cases of rubella.

References

1. PHE (2019). UK Measles and Rubella elimination strategy 2019.

2. UKHSA (2024). Measles, mumps and rubella: lab-confirmed cases in England 2023.

3. UKHSA (2024). Confirmed cases of measles in England by month, age and region: 2023.

4. UKHSA (September 2024). Confirmed cases of measles in England by month, age, region and upper tier local authority: 2024.

5. UKHSA (2024). Measles notifications and deaths in England and Wales: 1940 to 2023.

6. WHO Europe (2024). Measles and rubella monthly update: April 2024.

7. US Centers for Disease Control and Prevention (2022). Progress toward regional measles elimination worldwide, 2000 to 2021. Mortality and Morbidity Weekly Report: volume 71, number 47, pages 1489 to 1495