Subacute sclerosing panencephalitis in Papua New Guinean children: the cost of continuing inadequate measles vaccine coverage.

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Abstract

INTRODUCTION:

subacute sclerosing panencephalitis (SSPE) is a late rare and usually fatal complication of measles infection. Although a very high incidence of SSPE in Papua New Guinea (PNG) was first recognized 20 years ago estimated measles vaccine coverage has remained at ≤ 70% since and a large measles epidemic occurred in 2002. We report a series of 22 SSPE cases presenting between November 2007 and July 2009 in Madang Province PNG including localized clusters with the highest ever reported annual incidence.

METHODOLOGY/PRINCIPAL FINDINGS:

As part of a prospective observational study of severe childhood illness at Modilon Hospital the provincial referral center children presenting with evidence of meningo-encephalitis were assessed in detail including lumbar puncture in most cases. A diagnosis of SSPE was based on clinical features and presence of measles-specific IgG in cerebrospinal fluid and/or plasma. The estimated annual SSPE incidence in Madang province was 54/million population aged <20 years but four sub-districts had an incidence >100/million/year. The distribution of year of birth of the 22 children with SSPE closely matched the reported annual measles incidence in PNG including a peak in 2002.

CONCLUSIONS/SIGNIFICANCE:

SSPE follows measles infections in very young PNG children. Because PNG children have known low sero conversion rates to the first measles vaccine given at 6 months of age efforts such as supplementary measles immunization programs should continue in order to reduce the pool of non-immune people surrounding the youngest and most vulnerable members of PNG communities.