Measles
Measles infection in Northern Ireland
Public Health Agency
11 December 2024
Updates to this report will be published monthly.
1 Summary
- From 1 January 2024 to 08 December, 194 clinically suspected measles cases have been notified to the Public Health Agency.
- Of those notified during 2024 to 08 December, 21 were laboratory confirmed.
2 Background
Measles is a systemic viral infection caused by the measles virus. It is normally characterised by a fever, rash and respiratory illness. For more information about measles please visit NI Direct | Measles.
A vaccine against measles, which also provides protection against mumps and rubella (MMR), is included in the Northern Ireland childhood vaccination schedule at one year of age and at three years and four months. A regional MMR ‘catch-up’ campaign was delivered in Northern Ireland between February and June 2024 for anyone aged from one to 25 years, who had not already had two doses of MMR. For more information please visit NI Direct | MMR catch-up campaign, NI Direct | MMR and NI PHA | MMR vaccine catch-up.
Public and clinician awareness of measles has changed over time, especially during February 2024, which may contribute to changes in trends.
Details of case definitions and methods are at the end of this document. Data were correct at 08 December 2024.
3 Measles notifications, 2023-2024
The number of notified clinically suspected measles cases from the start of 2023 until the report date are shown (Table 3.1).
| 2023 | 2024 | |
|---|---|---|
| (N=19) | (N=194) | |
| Case category | ||
| Confirmed | 0 (0%) | 21 (10.8%) |
| Probable | 0 (0%) | 25 (12.9%) |
| Possible | 19 (100%) | 148 (76.3%) |
Please note: in the table above data for 2024 is up to 08 December
3.1 Trends
Measles notifications in Northern Ireland increased during February 2024 before decreasing by the end of March (Figure 3.1). The increases noted in February are likely attributable to an increase in reporting due to heightened awareness. There have been 21 laboratory confirmed measles cases reported in 2024. The last cases in Northern Ireland were in 2017 when six cases were confirmed. The supplementary table below shows counts of measles notifications recorded by week.
Figure 3.1: Incidence of measles notifications, by week of notification, all ages, 2023 - 2024.
4 Discussion
There have been 21 laboratory confirmed cases during 2024, the first since 2017. There was an increase in notifications of clinically suspected measles during February 2024, likely due to increased awareness and reporting. There is an increased risk of measles outbreaks due to a reduction in MMR vaccine coverage in Northern Ireland during recent years NI PHA | MMR vaccine coverage. Increasing coverage of the MMR vaccine is crucial to ensure widespread protection and prevent outbreaks of measles.
5 Methods
Measles notifications are reported by clinicians to the Public Health Agency and were extracted from the case management database. Measles is notifiable in Northern Ireland under the Public Health Act (1967) Northern Ireland.
Cases are presented by the date that they were recorded on the PHA database. Notified cases will be removed from future reports if PHA is notified that clinical investigations later result in an alternative diagnosis. Numbers may therefore reduce.
Data were processed in R.
5.1 Measles Case Definitions
Confirmed case: A case with laboratory confirmation of acute infection.
Probable case: A case with clinically classical symptoms of measles AND no previous MMR vaccinations or history of previous infection AND at least one of the following risk factors:
- Travel history in last 21 days.
- Attendance at large international mass gathering events.
- The case is a member of a community/population associated with low MMR vaccine uptake or measles outbreaks. Note this may only apply when there is transmission in Northern Ireland.
Possible case: A case with clinically classical symptoms of measles AND zero, one or two doses of MMR vaccine BUT no additional risk factors including those listed above.
The above case definitions are based on the current situation in Northern Ireland (as of 21 March 2024) and are subject to change.
6 Supplementary Table
| Case category | Total | |||
|---|---|---|---|---|
| Confirmed | Probable | Possible | ||
| Week of Report | ||||
| 2024-01-01 | 0 | 0 | 1 | 1 |
| 2024-01-08 | 0 | 0 | 1 | 1 |
| 2024-01-15 | 0 | 0 | 1 | 1 |
| 2024-01-22 | 0 | 0 | 1 | 1 |
| 2024-01-29 | 0 | 1 | 1 | 2 |
| 2024-02-05 | 0 | 1 | 2 | 3 |
| 2024-02-12 | 1 | 1 | 5 | 7 |
| 2024-02-19 | 1 | 9 | 12 | 22 |
| 2024-02-26 | 0 | 5 | 12 | 17 |
| 2024-03-04 | 0 | 1 | 7 | 8 |
| 2024-03-11 | 0 | 1 | 7 | 8 |
| 2024-03-18 | 0 | 0 | 9 | 9 |
| 2024-03-25 | 0 | 0 | 6 | 6 |
| 2024-04-01 | 0 | 0 | 2 | 2 |
| 2024-04-08 | 1 | 1 | 4 | 6 |
| 2024-04-15 | 2 | 0 | 2 | 4 |
| 2024-04-22 | 1 | 0 | 5 | 6 |
| 2024-04-29 | 5 | 0 | 2 | 7 |
| 2024-05-06 | 0 | 0 | 3 | 3 |
| 2024-05-13 | 0 | 0 | 8 | 8 |
| 2024-05-20 | 0 | 0 | 3 | 3 |
| 2024-05-27 | 0 | 1 | 5 | 6 |
| 2024-06-03 | 0 | 1 | 0 | 1 |
| 2024-06-10 | 0 | 0 | 2 | 2 |
| 2024-06-17 | 0 | 0 | 1 | 1 |
| 2024-06-24 | 0 | 0 | 1 | 1 |
| 2024-07-01 | 1 | 0 | 3 | 4 |
| 2024-07-08 | 0 | 0 | 2 | 2 |
| 2024-07-15 | 2 | 0 | 1 | 3 |
| 2024-07-22 | 0 | 0 | 4 | 4 |
| 2024-07-29 | 2 | 0 | 1 | 3 |
| 2024-08-05 | 0 | 0 | 3 | 3 |
| 2024-08-12 | 0 | 0 | 4 | 4 |
| 2024-08-19 | 1 | 0 | 0 | 1 |
| 2024-08-26 | 1 | 0 | 1 | 2 |
| 2024-09-02 | 2 | 2 | 1 | 5 |
| 2024-09-09 | 1 | 1 | 5 | 7 |
| 2024-09-16 | 0 | 0 | 2 | 2 |
| 2024-09-23 | 0 | 0 | 2 | 2 |
| 2024-09-30 | 0 | 0 | 1 | 1 |
| 2024-10-07 | 0 | 0 | 1 | 1 |
| 2024-10-14 | 0 | 0 | 2 | 2 |
| 2024-10-21 | 0 | 0 | 1 | 1 |
| 2024-10-28 | 0 | 0 | 4 | 4 |
| 2024-11-04 | 0 | 0 | 3 | 3 |
| 2024-11-11 | 0 | 0 | 1 | 1 |
| 2024-11-18 | 0 | 0 | 0 | 0 |
| 2024-11-25 | 0 | 0 | 2 | 2 |
| 2024-12-02 | 0 | 0 | 1 | 1 |
| Total | 21 | 25 | 148 | 194 |