Childhood pneumonia and meningitis in the Eastern Highlands Province, Papua New Guinea in the era of conjugate vaccines: study methods and challenges

Background: Pneumonia and meningitis are common causes of severe childhood illness in Papua New Guinea (PNG). The etiology of both clinical conditions in PNG has not been recently assessed. Changes in lifestyle, provision and access to healthcare, antimicrobial utilization and resistance, and the national childhood vaccination schedule necessitate reassessment. Methods: A prospective case-control study was undertaken, enrolling children <5 years of age to determine the contemporary etiology of clinically defined moderate or severe pneumonia or suspected meningitis. Cases were identified following presentation for inpatient or outpatient care in Goroka town, the major population centre in the Eastern Highlands Province. Following enrolment, routine diagnostic specimens including blood, nasopharyngeal swabs, urine and (if required) cerebrospinal fluid, were obtained. Cases residing within one hour’s drive of Goroka were followed up, and recruitment of healthy contemporaneous controls was undertaken in the cases’ communities. Results: 998 cases and 978 controls were enrolled over 3 years. This included 784 cases (78.6%) with moderate pneumonia, 187 (18.7%) with severe pneumonia and 75 (7.5%) with suspected meningitis, of whom 48 (4.8%) had concurrent pneumonia. The median age of cases was 7.8 months (Interquartile range [IQR] 3.9–14.3), significantly lower than community controls, which was 20.8 months (IQR 8.2–36.4). Half the cases were admitted to hospital (500/998; 50.1%). Recruitment of cases and controls and successful collection of diagnostic specimens improved throughout the study, with blood volume increasing and rates of blood culture contamination decreasing. The overall case fatality rate was 18/998 (1.8%). Of cases eligible for follow-up, outcome data was available from 76.7%. Low but increasing coverage of Haemophilus influenzae type B conjugate vaccines on the national schedule was observed during the study period: three dose DTPw-HepB-Hib coverage in children >3 months increased from 14.9 to 43.0% and 29.0 to 47.7% in cases and controls (both p < 0.001). Despite inclusion in the national immunization program in 2014, 2015 PCV13 three-dose coverage in cases and controls >3 months was only 4.0 and 6.5%. Conclusions: Recruitment of large numbers of pediatric pneumonia and meningitis cases and community controls in a third-world setting presents unique challenges. Successful enrolment of 998 cases and 978 controls with comprehensive clinical data, biological specimens and follow up was achieved. Increased vaccine coverage remains an ongoing health priority

Subacute Sclerosing Panencephalitis in Papua New Guinean Children: The Cost of Continuing Inadequate Measles Vaccine Coverage

Subacute sclerosing panencephalitis (SSPE) is a disabling and usually fatal brain disorder that typically occurs 3–10 years after acute measles infection. Papua New Guinea (PNG) has particularly high rates of SSPE. We report 22 cases of 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. Based on these cases, the estimated annual SSPE incidence in Madang province in 2007–2009 was 54/million population aged <20 years. Four sub-districts had an annual incidence >100/million population aged <20 years, the highest rates ever reported. Young PNG children do not respond well to measles vaccine. Because of this, efforts such as supplementary measles immunisation programs should continue in order to reduce the pool of non-immune older people surrounding the youngest and most vulnerable members of PNG communities