Cattram D. Nguyen, Australia

Murdoch Children's Research Institute Infection and Immunity

Presenter Of 1 Presentation

USING MULTIPLE INDICATOR CLUSTER SURVEYS TO DETERMINE PNEUMONIA BURDEN IN LAO PEOPLE’S DEMOCRATIC REPUBLIC (ID 891)

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

Author Of 14 Presentations

MONITORING PCV13 IMPACT USING NASOPHARYNGEAL CARRIAGE SURVEILLANCE AMONG CHILDREN WITH PNEUMONIA IN MONGOLIA (ID 965)

Abstract

Background

In 2015, Mongolia was among the earliest countries in Asia to introduce PCV. To monitor the impact of PCV13 introduction, we commenced nasopharyngeal carriage surveillance among children with pneumonia 6 months prior to vaccine introduction.

Methods

We recruited children 2-59 months of age presenting with pneumonia to district hospitals and the national Maternal and Child Health hospital in two districts in Ulaanbaatar. Clinical and demographic data, vaccination status and nasopharyngeal swabs were collected. A random sample of swabs were selected for testing each month. Samples were examined by lytA qPCR, with positives serotyped by microarray.

Results

We recruited 4980 children and tested 983 children from November 2015 to April 2018. The median age was 1.27 and 25.81% of cases were vaccinated in the first and second year following PCV13 introduction, respectively. 474 and 48.22% had received antibiotics in the 48 hours before admission.

Conclusions

Following PCV13 introduction in Mongolia, the prevalence of pneumococcal carriage remained stable while the prevalence of PCV13-type carriage decreased among children with pneumonia. Reductions in PCV13 carriage likely correspond to reductions in disease due to PCV13 types, since carriage is a precursor for disease.

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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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IMMUNOGENICITY OF A SINGLE DOSE OF PCV10 OR PCV13 AT 2 MONTHS OF AGE IN VIETNAM (ID 1007)

Abstract

Background

A 1+1 pneumococcal conjugate vaccine (PCV) schedule would increase its affordability for low and middle-income countries. The Vietnam Pneumococcal Trial II includes infants randomised to receive a 1+1 schedule of PCV10 or PCV13 at 2 and 12 months of age. This study measured the immunogenicity of a single dose of either PCV given at 2 months of age.

Methods

Serotype-specific IgG was measured at 3 and 12 months of age in PCV-vaccinated and unvaccinated controls using a WHO ELISA method.

Results

At 3 months, both vaccinated groups had higher antibody levels than controls for 7/10 serotypes (all except 6B, 14, 23F). The PCV10 group had higher antibody levels than the PCV13 group for 5/10 serotypes. Similar results were seen at 12 months, with higher antibody levels for all serotypes in the PCV10 group and 8/10 serotypes (all except 6V, 23F) in the PCV13 group compared with controls and higher antibody levels in the PCV10 than the PCV13 group for 7/10 serotypes.

Conclusions

A single dose of PCV in infancy is immunogenic and likely to provide some direct protection until the time of the booster dose. There may be a difference in the degree of protection offered by different PCVs.

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FACTORS ASSOCIATED WITH PNEUMOCOCCAL NASOPHARYNGEAL CARRIAGE: A SYSTEMATIC REVIEW (ID 389)

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

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)

USING MULTIPLE INDICATOR CLUSTER SURVEYS TO DETERMINE PNEUMONIA BURDEN IN LAO PEOPLE’S DEMOCRATIC REPUBLIC (ID 891)

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

INCREASED PCV10 IMMUNOGENICITY FOLLOWING A TWO-DOSE PRIMARY SERIES SEPARATED BY 4 MONTHS COMPARED WITH 2 MONTHS IN VIETNAMESE INFANTS (ID 963)

FACTORS ASSOCIATED WITH PNEUMOCOCCAL CARRIAGE IN CHILDREN AND ADULTS IN FIJI, USING FOUR CROSS-SECTIONAL SURVEYS (ID 224)

Abstract

Background

We describe factors associated with pneumococcal nasopharyngeal carriage in Fiji, using data from annual (2012-2015) cross-sectional surveys, pre- and post-introduction of ten-valent pneumococcal conjugate vaccine (PCV10).

Methods

Infants (5-8 weeks), toddlers (12-23 months), children (2-6 years), and their caregivers participated. Pneumococci were detected using lytA qPCR, with molecular serotyping by microarray. We used logistic regression to determine predictors of pneumococcal carriage.

Results

There were 8,109 participants. Pneumococcal carriage was associated with: years post-PCV10 introduction (global P<0.001), indigenous iTaukei ethnicity (aOR 2.74 [95% CI 2.17-3.45] P<0.001); young age (global P<0.001); urban residence (aOR 1.45 [95% CI 1.30-2.57] P<0.001); living with >2 children <5 years (aOR 1.42 [95% CI 1.27-1.59] P<0.001); poverty (aOR 1.44 [95% CI 1.28-1.62] P<0.001); and upper respiratory tract infection symptoms (aOR 1.77 [95% CI 1.57-2.01] P<0.001). Factors associated with PCV10 and non-PCV10 carriage were similar to those associated with overall carriage. Additionally, PCV10 carriage was associated with PCV10 vaccination (0.58 [95% CI 0.41-0.82] P=0.002) and cigarette smoke exposure (aOR 1.21 [95% CI 1.02-1.43] P=0.031, while non-PCV10 carriage was not associated with years post-PCV10 introduction.

Conclusions

Introduction of PCV10 reduced the odds of overall and PCV10 pneumococcal carriage in Fiji. Indigenous iTaukei ethnicity was positively associated with carriage after adjustment for PCV10.

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