EPIDEMIOLOGY OF CHICKENPOX IN FRANCE (1991-1995)

Study objectives-To decide whether a mass immunisation against chicken pox should be or should not be organised, it is important to have up t o date data on the disease and to have baseline data to further assess a mass immunisation strategy, if any. Design-Recent chickenpox epidem iology (age and sex distribution, seasonal dynamic and complications) in France are reviewed. Setting-The system works with about 500 Sentin elle general practitioners (SGPs) and has provided surveillance of fre quent communicable diseases in continental France since 1984. Particip ants-The data were collected by the computerised Sentinelle system. Th e Sentinelle system uses a videotex sewer that allows information exch ange, data entry, and synthetic return of information. Chickenpox was defined as a sudden onset of typical skin eruption with pruritus, leav ing scabs and associated with moderate fever. For each reported case, the SGP gave information on the age of the patient, sex, prevailing ch ildcare for the children, contacts and complications (skin superinfect ions, lower and upper respiratory infections, conjunctivitis and corne al infections, nervous system injuries, stomatitis and others). Spectr al analysis was used to detect cyclical patterns. Main results-Between 1991 and 1995, 15 817 cases of chickenpox were reported and provided the basis for the analysis. The yearly national incidence was 1.0-1.35 cases per 100 inhabitants. A pronounced annual periodicity of the inc idence was observed and confirmed by spectral analysis. Ninety two per cent of chickenpox cases occurred in children under 14 years of age w ith about 5% being under one. Complications were reported in 2% of the cases. Common complications reported were skin superinfections, lower and upper respiratory tract infections. However, 21 cases out of 318 complications were nervous system injuries including six encephalitis or cerebellar ataxia. Ah these cases recovered completely. Conclusions -Chickenpox ic usually a benign childhood disease. This study affords up to date observations on the disease in France. A large panel of com plications has been reported. This paper provides the first attempt to describe the epidemiology of chickenpox in France.