Child Mortality Following Measles Infection in Zurich, 1893-1928: A Study from the Pre‑Vaccination Period

Dr.Katarina Matthes (Institute of Evolutionary Medicine, University of Zurich), Prof. Dr. Flavia Wehrle (Child Development Center, University Children’s Hospital Zurich)

Measles is one of the most contagious infectious diseases, historically associated with high childhood mortality until the early 20th century. Beyond the acute illness, measles causes prolonged immune suppression and immune amnesia, increasing children’s risk of severe infections from other pathogens for months to years after recovery. The introduction of measles vaccination dramatically reduced both the incidence of measles and the mortality associated with it. However, recent outbreaks worldwide indicate that the WHO’s goal of eliminating measles by 2030 will likely not be achieved. This setback is especially concerning because measles remains a potentially lethal infection with far‑reaching effects on child health. Individual historical morbidity and mortality data from the pre‑vaccination era therefore offer a valuable opportunity to investigate whether and how measles infection increase susceptibility to other infectious diseases and increase mortality after infection.

There is no individual‑level evidence from the pre‑vaccination era quantifying the mortality risk in the first years after measles infection among young children. Historical morbidity and mortality records have never been linked in Switzerland, nor, to our knowledge, studied elsewhere using comparable historical pre‑vaccination data. However, for a clear understanding of the health and mortality effects following measles infection, examining historical morbidity and mortality data from a period unaffected by vaccination or modern medical care is essential, as it helps to interpret the true severity of measles and contextualize related risks in today’s public‑health debates.

The project aims to identify if children infected with measles have a higher probability of dying within the first years after infection compared with uninfected children of the same age and if so, what are the causes of death.

More specifically our project goals are:

1)     To transcribe the reported measles infections from infectious‑disease control books in the City of Zurich between 1893 and 1925 and link them to the city’s birth and death registers.

2)     To determine whether children under 5 years old who have had measles are at a higher risk of overall mortality before reaching 8 years of age, compared with children who have not had measles.

3)     To identify and compare the causes of death among children following a measles infection and among children without a history of measles infection.

This study will demonstrate the feasibility of linking infectious‑disease control books with birth and death registers, creating the first dataset that connects morbidity records from a period of high infectious‑disease burden with individual‑level birth and mortality data. It will lay the foundation for understanding childhood infectious diseases and their impact on subsequent health and mortality in the pre‑vaccine era.