No 50 - 2025

Three cases of measles detected in the Central Denmark Region

In week 49, the Department of Clinical Microbiology (KMA) at Aarhus University Hospital detected a case of measles in a child residing in the Central Denmark Region. The child had not yet reached the age for MMR vaccination. The case is considered travel-related from a country in Eastern Europe. The Danish Patient Safety Authority has been informed and has initiated the necessary contact tracing efforts.

This week, two additional cases have been detected in a child and an adult, both related to the first case. One patient had received post-exposure prophylaxis (PEP) in the form of normal human immunoglobulin but has developed mild measles symptoms. The other patient reported being vaccinated against measles and therefore did not receive PEP. Both patients have positive laboratory diagnostics performed at KMA, Aarhus University Hospital.

In 2024, there was a marked increase in measles cases both in Europe and globally – a development that has continued in 2025. In Denmark, 25 cases of measles were confirmed in 2024, the highest number since 2014, when 27 cases were detected. Surveillance of measles can be followed on the page Measles, Individually Notifiable Diseases – Surveillance in numbers, graphs, and maps (in Danish language). In 2025, there have so far been 11 cases of measles spread across four different regions. Only in three of the 11 cases has onward transmission occurred in Denmark.

Measles virus isolated from the first patient has been genotyped and belongs to genotype B3. It is a widely circulating type in 2025, with approx. 3,000 (out of over 7,000) reports from large parts of the world to WHO’s typing database, MEANS, and it has been detected in seven of the nine confirmed measles cases in Denmark this year. The specific B3 sequence ID has been reported to the typing database approx. 1,000 times this year, and it has previously been detected in a single case in Denmark in 2025. Measles virus from the two most recent patients has not yet been genotyped, but is expected to be identical to the genotype identified in the first patient.

International travel significantly increases the risk of infection, and although uptake of both MMR vaccines in the childhood vaccination program is high, it remains important to maintain focus on vaccination – for both children and adults who have not previously had measles or been vaccinated.

Prevention

The most important prevention against measles is MMR vaccination. In Denmark, the MMR vaccine is offered to all children as part of the childhood vaccination program at 15 months and 4 years of age.

There is no general recommendation to bring the vaccination time point forward, but if desired, the first dose may be given from 12 months of age and still count toward the childhood vaccination program.

Unvaccinated individuals aged 18 years and older who have not had measles may receive one free MMR vaccination – without prior antibody testing. If a person has already received one MMR vaccine during childhood, no further vaccination is necessary, EPI-NEWS 7–8/2024 .

Management of suspected measles

For the sake of contact tracing and the possibility of providing preventive treatment, sampling should be performed as early as possible in the course of illness. It is important that persons suspected of having measles do not stay in waiting rooms with other patients, as measles is extremely contagious, Guidelines on prevention and management of measles (in Danish language).

The following samples are taken when measles is suspected:

• Throat swab and urine for detection of measles virus (morbillivirus) RNA by PCR
• A blood sample for measles virus (morbillivirus) IgM/IgG antibody determination.

Because characterization of measles virus is important for contact tracing and mapping, all suspected and confirmed measles virus–positive samples should be sent as quickly as is practically possible. It is recommended to contact the on-call virologist at SSI by phone (weekdays during daytime: +45 40336379; after 15:30 and on weekends/holidays: on-call epidemiologist +45 41317404) to prepare the laboratory for sample arrival and thereby avoid unnecessary diagnostic delay.

For further guidance on sampling, refer to the diagnostic handbook (in Danish language), or alternatively regional/local clinical microbiological guidelines and EPI-NEWS 9/2024 .

Management of persons exposed to measles

The Danish Patient Safety Authority identifies and informs close contacts about precautions and the possibility of PEP. In cases of confirmed exposure – that is, contact with a laboratory-confirmed or epidemiologically linked case – the following is offered to non-immune contacts:

• MMR vaccination (up to three days after first contact with the infected person)

or

• Normal human immunoglobulin (up to six days after first contact with the infected person).

The clinical assessment of whether PEP should be offered is made by the treating physicians – potentially in collaboration with SSI. See details regarding prophylaxis after exposure here (in Danish language).

Notification

Suspected measles must be reported by phone by the treating physician to the Danish Patient Safety Authority, Supervision and Guidance East/West, EPI-NEWS 44b/2023  , based on the following criteria:

• Symptoms compatible with measles AND relevant exposure (a person in the surroundings with laboratory-confirmed measles infection or travel to an area where measles occurs)
  OR

• Symptoms compatible with measles and detection of morbillivirus IgM
  OR
• Detection of morbillivirus RNA (PCR).

Confirmed cases of measles must additionally be notified in writing to the Danish Patient Safety Authority, Supervision and Guidance East/West, as well as to SSI. This is done via the electronic reporting system (SEI2). See link for additional information and guidance (in Danish language).

(J. Grau. P.H. Andersen, Department of Infectious Disease Epidemiology and Prevention, L.D. Rasmussen, K.S.S. Gudmundsson, Department of Virology and Microbiological Preparedness, M.K. Thomsen, Aarhus University Hospital, A. Hempel-Jørgensen, Danish Patient Safety Authority, Supervision and Guidance West)