A high concentration of a Moroccan variant of the measles virus, genotype B3, has been discovered in sewage in Brussels, sparking health concerns throughout Europe. The alarming finding was reported by researchers from KU Leuven, indicating an unprecedented level of the virus in the local environment.
This discovery raises significant concerns, particularly as Belgium grapples with a measles outbreak that has been escalating across Europe. The outbreak has seen a recent surge in cases, mirroring a troubling situation in Morocco, where a major outbreak of the same genotype has resulted in over 25,000 cases since late 2023, with at least 120 deaths attributed to the disease.
Elke Wollants, lab manager at the Rega Institute of KU Leuven, highlighted the severity of the situation in a recent interview with the local news outlet Het Laatste Nieuws. “The concentration is unprecedented,” she stated, noting a peak in virus measurement on March 11, 2025. Despite these alarming findings, health institute Vivalis has reported only 18 measles cases in Brussels for the current year, a figure Wollants believes underrepresents the actual threat. “This is likely an underestimate,” she cautioned, emphasizing that the significant viral load associated with genotype B3 may skew results.
The spread of the genotype B3 variant is not limited to Brussels. With the virus being reported in neighboring countries, health officials are increasingly concerned about the potential for widespread infection. Over the past two weeks alone, the Netherlands reported 45 new cases, contributing to growing anxiety in countries like Spain and France, where similar outbreaks have begun to emerge.
According to a report from the European Centre for Disease Prevention and Control (ECDC), which analyzed data from February 1, 2024, to January 31, 2025, Belgium recorded a total of 551 measles cases during that period, making it one of the countries with the highest incidences in Europe. Romania, Italy, and Germany reported even larger numbers of cases. Nearly 34 cases have already been documented in Flanders through the end of February, nearly equaling the total number reported throughout all of 2023.
Wollants expressed urgency regarding the need for vaccination, urging residents to verify their immunization status through the official health website, www.mijngezondheid.be. She noted that many vaccinations were not digitally recorded in the past, making it crucial for residents to consult their previous vaccination cards or health records to ensure they are protected against measles.
As the situation remains critical, particularly for those born before 1970—who may have experienced measles and thereby gained immunity—current data shows concerning gaps in immunity among individuals aged 30 to 40. Many in this group may not have received vaccinations during childhood. “It is imperative that those who have not been fully vaccinated receive a free catch-up vaccination from their doctor,” stressing that anyone uncertain of their status should also consider double vaccinations to ensure protection.
Health officials have noted a notable increase in vaccination requests, with approximately 20,000 orders for vaccines recorded since January 2025. “The heightened media coverage and awareness campaigns appear to be having an effect,” remarked Joris Moonens, spokesperson for the Flanders Department of Health, underscoring that although the figures are troubling, Belgium's relatively high vaccination rates have mitigated the effects compared to other affected countries like Romania and Morocco.
Nevertheless, the symptoms of measles can lead to serious complications, including pneumonia, encephalitis, and even death. Symptoms typically include the characteristic red spots starting behind the ears and spreading across the body, along with high fever, diarrhea, vomiting, coughing, and a runny nose. “Children can die from measles,” Wollants reminded the public. This stark reminder stresses the importance of maintaining vigilant monitoring and response to the outbreak.
The health crisis is compounded by the regionalization of disease reporting in Belgium, established following the sixth state reform in 2011. Each region maintains its own statistics, complicating efforts to gain a comprehensive national perspective on the outbreak. As scientists and health officials contemplate the implications of the latest reports, the need for integrated approaches to public health and responsive vaccination strategies becomes increasingly vital in overcoming this public health challenge.
With the rising threat posed by the measles virus, particularly the B3 genotype linked to the Morocco outbreak, authorities are calling for renewed vigilance and proactive health measures. As families and individuals prepare for the coming weeks, understanding their vaccination status and prioritizing public health will be critical to safeguard communities against a disease that is both contagious and potentially lethal.
