VARICELLA-ZOSTER VIRUS-INFECTION IN AUSTRALIA

Objective: To determine the epidemiology of varicella-zoster virus (VZ V) infection in Australia using currently available data sources. Desi gn: Analysis of national death data (23 years), congenital and neonata l cases (one year) and attendances at sentinel general practices (two years); hospital admissions in NSW and SA (six years); serological stu dies in 1995 involving antenatal clinics in Sydney and Brisbane and ch ild-care centre staff and refugees in Sydney: and case-ascertainment i n 1995 in South Western Sydney among public hospital staff, childcare centre staff and the community. Results: In Australia, there have been an average of 3.5 deaths from chickenpox (mostly children) and 11 fro m herpes zoster (mostly older people) each year since 1980. The crude death rate for chickenpox has declined (p>0.05). In 1995, there were 1 4 cases of neonatal and two of congenital varicella. Average annual ad mission rates for NSW and SA showed 1,200 hospital bed-days used for c hickenpox, more than 20% with complications, and more that 7,300 bed d ays for zoster; annually more that 880 in-patient admissions were comp licated by VZV. Most people encounter the virus in their first 15 year s, but some remain susceptible into their 20s; 25% of cases and 37% of hospital admissions for chickenpox occur in people greater than or eq ual to 15 years of age. Conclusion: VZV infection involves people of a ll ages. It causes substantial morbidity and mortality, particularly a t the extremes of life. The death rate from chickenpox but not zoster has fallen since the introduction of acyclovir in the 1980s. Surveilla nce of VZV infection must be given priority once vaccines become avail able, to monitor changes in morbidity and mortality.