THE CLINICAL, SOCIAL AND ECONOMIC BURDEN OF CHICKENPOX IN A DEVELOPED COUNTRY
*Norman Noah, Helen Rawson
London School of Hygiene & Tropical Medicine and PHLS Communicable Disease Surveillance Centre

A common but mild disease may place a greater economic burden on a community than one which is serious but rare. Chickenpox is common in children but more serious in adults. It may be becoming more common in adults, especially in the immuno- compromised and in pregnant women. We studied the burden of chickenpox in 1997 in England and Wales at all levels of severity, as follows:

· those with clinical disease, no health service usage (phase1)
· those attending primary care (2)
· hospital admissions (3)
· deaths (4)

The baseline populations from two general practices were used as a denominator for phase 1 (22,181 persons). Nineteen General Practice populations were used for phase 2 (192,485 persons). 17 General Hospitals in one English Region (population 3.5m) were used for phase 3 and deaths covering a 3 year period (1995-1997) for England and Wales (population 50m) for phase 4.

Phase 1: Nearly 85% of 897 respondents who had chickenpox consulted a health service professional.

Phase 2: 677 patients with chickenpox in primary care were ascertained; 555 (83%) were interviewed. Mean duration of illness was 9.0 days (range 1-70). Mean days lost from normal activities were 2.6 days (nursery groups) 5.2 days (school) 5.5 days (employment). The mean cost of chickenpox per case for primary care was £178.30.

Phase 3: 190 patients were admitted to hospital with chickenpox. Mean in-patient hospital stay was 3.9 days. Of 104 patients reported by infection control teams, 72% were interviewed (22% were uncontactable). Mean duration of in-patient stay was 4.7 days (range 1-17), duration of illness 11.2 days (range 3-34). Cases in socio-economic groups 1 and IIIN were over-represented. The mean cost per hospitalised patient was £2,621. This varied considerably by age group. 4 of the 104 patients died. The cost of inpatient stay for deceased cases was £8,373 (range £1,136 - £27,363).

Phase 4: We estimated 30 deaths per year from chickenpox, equivalent to a case-fatality rate of 9.22/100,000. Adults accounted for 19% of GP consultations, and for 81% of deaths. Twice as many men died from chickenpox as women.

Chickenpox is a serious illness in developed countries, especially in adults.

Corresponding Author: Norman Noah, Professor of Epidemiology, Communicable Disease Surveillance Centre, 61 Colindale Avenue, London NW9 5EQ. London School of Hygiene & Tropical Medicine, Keppel Street, London WC1A 7HT, United Kingdom