Abstract
Nearly everybody is infected with varicella zoster virus (VZV), which causes varicella (chickenpox) and herpes zoster (shingles) (HZ). Varicella is usually a benign, but very itchy skin disease, predominantly occurring in childhood. HZ is a painful skin disease mainly affecting adults >50 years old. Both diseases can lead to serious complications. The burden of varicella and HZ is substantial and could be prevented by vaccination. Despite the availability of safe and efficacious vaccines, Norway currently does not implement vaccination programs against varicella and HZ.
The aims of the thesis were to characterize the healthcare burden of varicella and HZ in Norway in the pre-vaccine era by estimating rates of primary- and hospital care cases and assessing the levels of immunity against VZV in general population and among pregnant women. This aims to inform the national policy decision on the use of varicella and HZ vaccines, and guide current screening policies for varicella in obstetric populations.
Only 73% of the Norwegian population had immunity against VZV compared to >90% reported in most European countries. In addition, a small proportion of pregnant Norwegian women who were not immune to VZV got infected during their pregnancies, thereby increasing the risk of unfavourable health outcomes for themselves and for their offspring.
The data from national health registries showed that 10,881 varicella patients and 11,181 HZ patients were treated annually in primary care. Moreover, 361 varicella patients and 1,218 HZ patients were hospitalized annually. At least 47% of hospitalized HZ cases had complications. Very few patients were vaccinated against varicella and none against HZ during the study period 2008-2014.
Varicella and HZ cause considerable healthcare burden in Norway. There is an urgent need to develop robust knowledge-based national vaccine recommendations for both diseases and revise screening guidelines for VZV susceptibility in pregnancy.