Subacute sclerosing panencephalitis in papua new guinean children: the cost of continuing inadequate measles vaccine coverage.

Ann M Powers,Laurens Manning,Ilomo Hwaiwhanje,Harin A Karunajeewa,Henry Edoni,David Smith,Ivo Mueller,Moses Laman,Timothy M E Davis,Peter M Siba

doi:10.1371/journal.pntd.0000932

Abstract

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

Highlights

Subacute sclerosing panencephalitis (SSPE) is a late, rare and usually fatal complication of measles infection
We report 22 cases of Papua New Guinea (PNG) children presenting to the provincial referral hospital in Madang Province who probably contracted acute measles when,12 months of age during a national epidemic in 2002 and who developed SSPE 5–7 years later
Young PNG children do not respond well to measles vaccine. Efforts such as supplementary measles immunisation programs should continue in order to reduce the pool of nonimmune older people surrounding the youngest and most vulnerable members of PNG communities

Summary

Introduction

Subacute sclerosing panencephalitis (SSPE) is a late, rare and usually fatal complication of measles infection. The first reports of an unusually high incidence in Papua New Guinea (PNG) were published in the early 1990’s [5], with rates between 1988 and 1999 that varied from 13 [5] to 98 [6] per million population ,20 years of age. These data need to be interpreted against fluctuations in the incidence of acute measles infection over the preceding decade, and should take into account background vaccination coverage and the possibility that localized clusters may contribute disproportionately to overall incidence rates estimated at provincial or country level. Published PNG data to date have come from highland areas which may not be representative of the country as a whole

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