Pneumococcal carriage rates in Papua New Guinean (PNG) children are among the highest globally. One aim of the multi-site PneuCAPTIVE study is to determine the impact of PCV13 (introduced in 2014) on nasopharyngeal carriage in PNG.
Nasopharyngeal (NP) swabs and blood were collected from children aged <5 years with moderate or severe pneumonia, and/or suspected meningitis at Eastern Highlands Provincial Hospital or outpatient clinics in Goroka (2016-2018). Pneumococci were identified and quantified by lytA qPCR, and serotyped by microarray. IPD was identified by standard blood culture.
PCV13 coverage was 62%. 1043 were enrolled: 90% had pneumococcal carriage, with median density of 6.59 log10 genome equivalents (GE)/ml (IQR 6.00-7.11). Serotype data were available on 914 cases: 37% were PCV13-types; and 55% had multiple pneumococcal-type carriage. 74 different serotypes and genetic lineages of acapsular pneumococci were identified, the most common being acapsular lineage NT2>19A>15B/C>16F>14. PCV13-type carriage was 28% in vaccinated children vs 46% in unvaccinated children. IPD was confirmed in 7 cases (vaccinated – serotype 1; unvaccinated – serotypes 2, 6B, 15F, 19A, 23A, 29): 4/7 carried the homologous serotype.
There is some evidence of PCV13 being effective against PCV13-types but the high diversity of serotypes in PNG warrants extended valency vaccines.