Christopher C. Blyth, Australia

Telethon Kids Institute Wesfarmers Centre of Vaccines and Infectious Diseases

Author Of 8 Presentations

PNEUMOCOCCAL CONJUGATE VACCINE IS EFFECTIVENESS AGAINST HYPOXIC PNEUMONIA IN LAOS, MONGOLIA AND PAPUA NEW GUINEA: A NOVEL CASE-CONTROL VARIANT STUDY (ID 852)

Abstract

Background

We describe a novel approach to determine PCV13 effectiveness (VE) against hypoxic pneumonia in children admitted with pneumonia in Lao PDR (Laos), Mongolia and Papua New Guinea (PNG).

Methods

A 3-5 year prospective hospital-based observational study of children <59 months admitted with pneumonia was undertaken. Pneumonia was defined using the 2013 WHO definition. Hypoxia was defined as an oxygen saturation <90% in room air or requiring oxygen supplementation during hospitalisation. PCV13 status was determined by written record. VE was calculated using logistic regression comparing the odds of hypoxia between vaccinated and undervaccinated pneumonia cases. To handle potential confounders a propensity score (PS) analysis using inverse probability of treatment weighting (IPW) was used. In Laos, multiple imputation (MI) analysis was undertaken for missing data.

Results

The VE against hypoxic pneumonia were: in Laos, unadjusted 23% (95% CI: -9, 46%; p=0·14), PS adjusted IPW 37% (6, 57%; p=0·02), MI adjusted 35% (7, 55%; p=0·02); in Mongolia, unadjusted 33% (26, 40%; p<0.001), PS adjusted IPW 33% (16, 47%; p<0.001); and in PNG, unadjusted 6% (-15, 24%; p=0.532), PS adjusted IPW 36% (17, 51%; p=0.001).

Conclusions

Our novel approach shows that PCV13 is effective against hypoxic pneumonia. PCV13 will contribute to reducing child mortality.

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HIGH RATES OF MULTIPLE NASOPHARYNGEAL PNEUMOCOCCAL CARRIAGE IN CHILDREN WITH PNEUMONIA IN PAPUA NEW GUINEA FOLLOWING PNEUMOCOCCAL CONJUGATE VACCINE INTRODUCTION (ID 731)

Abstract

Background

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.

Methods

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.

Results

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.

Conclusions

There is some evidence of PCV13 being effective against PCV13-types but the high diversity of serotypes in PNG warrants extended valency vaccines.

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SUBSTANTIAL INDIRECT PROTECTION AGAINST IPD AND PNEUMONIA HOSPITALISATIONS AT LOW LEVELS OF VACCINE COVERAGE IN AUSTRALIA, YET HIGH COVERAGE REQUIRED FOR NEAR-ELIMINATION (ID 854)

BREAKTHROUGH IPD FOLLOWING 13VPCV SCHEDULE CHANGE FROM 3+0 TO 2+1 AMONG AUSTRALIAN CHILDREN (ID 921)

Session Name
Population Sciences - Epidemiology, Economics, and Mathematical Modelling

Abstract

Background

In mid-2018, the Australian infant 13vPCV schedule changed from three primary doses (3+0) to two primary doses and a 12 month booster (2+1) to address increasing breakthrough cases of invasive pneumococcal disease (IPD), predominantly in children >12 months. We assess the impact of this schedule change on breakthrough IPD.

Methods

All cases of breakthrough IPD following 13vPCV (2012-2018) reported to the national notifiable diseases surveillance system were analysed by age, serotype and clinical syndrome. In addition, cases in the first 3 quarters post-schedule change were compared to corresponding period pre-change.

Results

Annual 13vPCV breakthrough case counts in children aged <5yrs (figure) increased progressively from 2012(n=3) to 2017(n=73) but declined in 2018 (n=65). Of 306 total cases, 297 were caused by serotypes 3(41%),19A(38%) and 19F(19%). Those aged 12-24 months accounted for 41% (n=125) of cases. Over two thirds of cases (n=211) were pneumonia and 12 were meningitis. Breakthrough cases in children aged >12 months post-schedule change were still more than that in the comparison pre-change period (41 versus 31).

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Conclusions

The change to administer the third scheduled PCV dose as a booster (2+1)is expected to reduce breakthrough IPD by improving both direct and indirect protection from 13vPCV but discernible impact is not yet observed.

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