Varicella zoster virus (VZV) predominantly affects children in temperate countries, with near-universal seroconversion occurring by late childhood. However, in tropical regions, VZV infection is common in adolescents and adults. This review identifies age-related VZV seroprevalence patterns in a number of Asian countries which indicate that seroconversion in tropical countries occurs at a later age than in temperate countries. Seasonal and regional variations in acute disease within some Asian countries suggest that temperate climates might favour transmission of the varicella virus, with incidence peaking during cooler months and in cooler, more temperate regions. VZV infection is often more severe in adults than in children, suggesting that tropical countries may be at risk of greater morbidity and mortality as a result of later-age seroconversion. Susceptibility of pregnant women and their infants, and of people infected with HIV/AIDS is also cause for concern. Vaccination may be beneficial in reducing the impact of VZV in Asian populations.
Little is known about varicella-zoster virus (VZV) susceptibility in US-bound refugee populations, although published data suggest that VZV seroprevalence in these refugee populations may be lower than US populations. We describe VZV seroprevalence in five US-bound refugee groups: (1) Bhutanese in Nepal, (2) Burmese on the Thailand-Burma (Myanmar) border, (3) Burmese in Malaysia, (4) Iraqi in Jordan, and (5) Somali in Kenya. Sera were tested for presence of VZV IgG antibodies among adults aged 18-45 years. Overall VZV seroprevalence was 97% across all refugee groups. VZV seroprevalence was also high across all age groups, with seroprevalence ranging from 92-100% for 18-26 year-olds depending on refugee group and 93-100% for 27-45 year-olds. VZV seroprevalence was unexpectedly high in these five US-bound refugee groups, though may not reflect seroprevalence in other refugee groups. Additional studies are needed to better understand VZV seroprevalence in refugee populations over time and by region.
Varicella-zoster virus (VZV) infections are a particular problem in healthcare settings. A survey of chickenpox was carried out amongst healthcare workers (HCWs) following potential ward exposures. A prior history of chickenpox was given by 61/98 (62.2%). Of 64 HCWs tested for VZV IgG, 10 (15.6%) were seronegative, indicating susceptibility. The sensitivity, specificity, positive predictive value, and negative predictive value of a history of prior chickenpox were 57.4%, 90%, 96.4%, and 31.0%, respectively. VZV screening of HCWs without a history of chickenpox, and vaccination of susceptible HCWs should be undertaken in this hospital.
Primary varicella-zoster virus infection in children with haematological malignancy is a life threatening disease. In one year, there were 10 cases of varicella and 2 cases of zoster among these children as well as 5 mothers who were accompanying their children who developed varicella in the oncology ward. Two children died of fulminating disease despite aggressive antiviral and supportive treatment. Acyclovir can be used in treatment and prophylaxis in exposed susceptible children. Varicella -zoster immune globulin is not available in this country. Vaccination with live virus has been shown to be protective in immunocompromised children and needs consideration.