Generating epidemiological evidence for controlling emerging infectious disease outbreaks

Ewijk, C.E. van (2026)

Doctoral Thesis

This thesis focuses on two infectious diseases that caused epidemics in the Netherlands in recent years: COVID-19 and mpox. COVID-19 was a new disease that affected people worldwide. Mpox suddenly became more easily transmissible between humans and as a result appeared in new regions outside Africa, including Europe and the Netherlands. 

Various measures are used to control epidemics, such as social distancing, isolation, quarantine, and vaccination. When a new disease emerges, it is unclear which measures are most effective, so research into the disease’s characteristics and effective interventions is essential. This thesis investigated these topics. 

Research in a nightclub showed that easing COVID-19 measures can be risky when few people are vaccinated, or when new variants circulate that reduce protection by previous infection or vaccination.
Elderly people in nursing homes were less well protected against infection as early as six months after their COVID-19 vaccination. 

Especially men who have sex with men were at higher risk of mpox.
To prevent transmission, contacts had to quarantine for 21 days. Unfortunately, vaccination that was offered after exposure was often too late to prevent illness. 

The recommendations from this thesis can help optimise the response to future epidemics. 

• Emerging infectious diseases
• Epidemics
• Prevention and control measures
• Outbreak response Mpox
• COVID-19
• Source and contact investigation
• Infectious diseases
• Preparedness

• All authors: Ewijk, C.E. van
• Supervisor: Hof, S. van den
• Co-supervisor: Hahné, S.J.M.; Knol, M.J.
• Committee: Bom, J.G. van der; Timen, A.; Schim van der Loeff, M.F.; Hoebe, C.J.P.A.; Bruijning-Verhagen, P.C.j.L.
• Qualification: Doctor (dr.)
• Awarding Institution: Faculty of Medicine, Leiden University Medical Center (LUMC), Leiden University
• Date: 2026-05-08
• ISBN (print): 9789465372334