Eurosurveillance - Volume 30, Issue 50, 18 December 2025

In September 2023, monkeypox virus (MPXV) clade Ib emerged in Kamituga, a mining zone in South Kivu, Democratic Republic of the Congo (DRC), primarily through sexual transmission.

We aimed to investigate cases in a MPXV clade Ib outbreak in Uvira, eastern DRC.

From June to October 2024, we collected demographic, exposure and clinical data from suspected mpox cases at Uvira hospital and in households. The virus was identified by PCR. We investigated putative transmission patterns, disease severity and risk factors.

We identified 973 suspected cases: 415 (42.7%) were tested with PCR and 322 (77.6%) were confirmed. The median age of suspected cases was 9 years (interquartile range (IQR): 3–20 years), with 620 (63.7%) aged < 15 and 344 (35.4%) < 5 years. Severe disease (≥ 100 lesions) was more common in cases aged < 15 years (25.6%; 142/554) than others (16.1%; 49/304; p < 0.001). Twenty-two (12.2%) of 181 cases aged < 5 years had acute malnutrition. Seven cases died; the overall case-fatality ratio was 0.7%, and in infants (aged < 1 year) it was 3.9% (5/127). Of 329 suspected cases tested for HIV, six (1.8%) were positive. Nineteen (14.5%) of 131 females aged 15–49 years were pregnant. Most reported exposures to suspected mpox cases occurred in households (67.9%; 298/439). Sexual (6.0%; 19/318) or healthcare-related occupational exposures (1.4%; 6/417) were less common. Animal exposures were few (5.0%; 39/776) and predominantly domestic (97.4%; 38/39).

This child-centred outbreak, driven by non-sexual transmission, underscores the need for paediatric vaccines, nutritional support and household interventions. Adult-focused responses alone may be insufficient to control the outbreak.

Pertussis remains a serious threat to young infants. In Norway, infants receive an acellular pertussis vaccine (aP) according to a 2 + 1 schedule at 3, 5 and 12 months of age, delivered as a hexavalent vaccine.

We aimed to study susceptibility to pertussis in mothers and infants to guide decisions regarding vaccination in pregnancy.

In this prospective observational study, we included 366 mother/infant pairs during 2020–2023, collecting blood samples from mothers in late pregnancy, cord blood at delivery and from infants before their first and after their third vaccine dose. We retrieved health registry data on vaccination and pregnancy-related information. IgG antibody levels against pertussis-antigens, diphtheria and tetanus were measured using a multiplex immunoassay.

Of the pregnant women, 48% (174/366) had low levels of antibodies against pertussis toxin (PT) defined as below 5 IU/mL. Maternal antibodies declined in infants from birth until first vaccination, leaving 72% (154/215) of infants with anti-PT IgG levels below 5 IU/mL. All infants responded well to vaccination and we found no evidence of blunting from high levels (> 40 IU/mL) of maternal antibodies against PT. Infants of mothers who received an aP-containing booster vaccine within 2 years before pregnancy displayed low anti-PT IgG levels, with 58% (15/26) having levels below 5 IU/mL.

A high proportion of pregnant women and their infants under 3 months of age had low anti-PT antibody levels, indicating high susceptibility to pertussis. The results support the introduction of vaccination against pertussis during pregnancy in Norway.