Research and analysis

Laboratory confirmed cases of measles, mumps and rubella in England: April to June 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 second quarter of 2024 (April to June). 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:

• Measles: confirmed cases
• Mumps: confirmed cases
• Rubella: confirmed cases

The results from all samples tested at Colindale are reported to 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 14 to 27 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	4,724	2,018 (42.7)	559	884	202	6.30
Mumps	1,545	695 (45.0)	90	36	7	2.60
Rubella	162	52 (32.1)	13	0	0	0.28

*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 April and June 2024, 1,086 laboratory confirmed cases of measles were reported in England, an increase of 18% compared to the previous quarter (n=887) (2) (Figure 1).

In January 2024 UKHSA declared a national measles incident response initially due to a large outbreak in Birmingham, this was followed by a rise in cases in London and small clusters in other regions, see details of the linked outbreak here (3).

The majority, 61.8% (671/1,086), of cases were in children aged 10 years or younger. 3.7% (40/1,086) of cases were previously vaccinated with one dose of the MMR vaccine and 2.8% (30/1,086) with at least two doses. The remaining cases were either too young to be vaccinated, had the vaccine(s) pre- or post-exposure or had no vaccine recorded.

Of the 1,086 cases reported this quarter, only 49 (4.5%) cases were classified as imported or import-related. However, data on imported cases is incomplete and should be interpretted with caution.

The vast majority of cases, therefore, were the result of community-level transmission in England. Regional and age-level breakdowns can be found here.

This quarter, 9 laboratory confirmed cases were reported in Northern Ireland and 15 in Wales. In Scotland, 8 laboratory confirmed cases were reported and of these, 5 were thought to have been imported and related to international travel outside the UK.

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

Since January, UKHSA has published regular epidemiological updates on the national measles incident on the UKHSA data dashboard and the measles epidemiology webpage.

Across the WHO Europe Region there has been an increase in measles infections, with cases reported in 49 countries (92% of Europe Region countries) between July 2023 and June 2024. The vast majority of cases were reported by Kazakhstan (n=40,525), Azerbaijan (n=30,346) and the Russian Federation (n=20,949) (4). Measles activity is also present across WHO African, Eastern Mediterranean and South-East Asian regions (5). 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 (6).

All suspected cases of measles and rubella should be reported promptly to HPTs, a risk assessment conducted and an Oral Fluid Kit (OFK) sent for confirmatory testing even if local diagnostic testing is underway (6). This quarter, an oral fluid sample was returned for only 43% of all suspected measles cases reported in England, well below the 80% WHO target (Table 1).

Mumps

In England, there were 43 laboratory-confirmed mumps infections in the period April to June 2024 – a reduction of nearly one third since the last quarter (n=60) (5).

Twelve of the 43 cases (28%) this quarter were in children below the age of 15 years. Of these, 50% (6/12) were vaccinated with one dose of MMR, and 25% (3/12) had received at least two doses. Of the 31 cases in those aged 15 years and older, 13% (4/31) were vaccinated with 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 June 2024

Rubella

There were no laboratory confirmed cases of rubella reported in this quarter.

References

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

2. UKHSA (2024). ‘Laboratory confirmed cases of measles, rubella and mumps in England: January to March 2024’. Health Protection Report volume 18 number 8

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

4. WHO Europe (2024). ‘Measles and rubella monthly update: July 2024’

5. WHO (2024). ‘Global measles vaccination – Global measles outbreaks’

6. 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 1,489 to 1,495