Deaths from chickenpox in adults are decreasing

EDITOR—On the basis of death certificates from the Office for National Statistics from 1995 to 1997, Rawson et al conclude that deaths as a result of chickenpox are increasing in adults in England and Wales.1 More up to date figures from the Office for National Statistics, however, show that chickenpox mortality is decreasing in adults (from 32 deaths in 1996 to 18 in 2000—see figure (a)). Furthermore, the number of deaths from chickenpox and case fatality rates were significantly higher in 1995-7 (period of the analysis) than at any other period. The claim by Rawson et al that deaths in adults are rising is therefore misleading.

The change in age related varicella mortality is the result of a shift in the age distribution of infection. Over the past two decades there has been an increase in cases in the youngest age group (possibly due to greater attendance of day-care).2^–4 Over the same time period there has been a gradual increase in reported incidence in adults, which peaked in the late 1980s and has been falling since (figure (b)). This is broadly reflected in the gradual decrease in deaths in adults during the past decade. The exception to this trend are 1996 and 1997—exactly the time period when Rawson et al performed their study. What has caused these large shifts in the incidence of varicella in adults is still largely unexplained.

Epidemiology of chickenpox in United Kingdom needs further investigation

EDITOR—Rawson et al highlight the …