Skip to content
The Kids Research Institute Australia logo
Donate

Discover . Prevent . Cure .

High Nasopharyngeal Carriage of Non-Vaccine Serotypes in Western Australian Aboriginal People Following 10 Years of Pneumococcal Conjugate Vaccination

Invasive pneumococcal disease (IPD) continues to occur at high rates among Australian Aboriginal people.

Authors:
Collins DA, Hoskins A, Bowman J, Jones J, Stemberger NA, Richmond PC, Leach AJ, Lehmann D

Authors notes:
PLoS ONE. 2013;8(12):e82280

Keywords:
Pneumococcal, vaccine, seven-valent pneumococcal conjugate vaccine, 7vPCV, Aboriginal

Abstract:
Invasive pneumococcal disease (IPD) continues to occur at high rates among Australian Aboriginal people.

The seven-valent pneumococcal conjugate vaccine (7vPCV) was given in a 2-4-6-month schedule from 2001, with a 23-valent pneumococcal polysaccharide vaccine (23vPPV) booster at 18 months, and replaced with 13vPCV in July 2011.

Since carriage surveillance can supplement IPD surveillance, we have monitored pneumococcal carriage in western Australia (WA) since 2008 to assess the impact of the 10-year 7vPCV program.

Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were carried by 71.9%, 63.2% and 63.3% respectively of children <5 years of age, and 34.6%, 22.4% and 27.2% of people ≥5 years.

Of 43 pneumococcal serotypes identified, the most common were 19A, 16F and 6C in children <5 years, and 15B, 34 and 22F in older people.

7vPCV serotypes accounted for 14.5% of all serotypeable isolates, 13vPCV for 32.4% and 23vPPV for 49.9%, with little variation across all age groups.

Serotypes 1 and 12F were rarely identified, despite causing recent IPD outbreaks in WA.

Complete penicillin resistance (MIC ≥2µg/ml) was found in 1.6% of serotype 19A (5.2%), 19F (4.9%) and 16F (3.2%) isolates and reduced penicillin susceptibility (MIC ≥0.125µg/ml) in 24.9% of isolates, particularly 19F (92.7%), 19A (41.3%), 16F (29.0%).

Multi-resistance to cotrimoxazole, tetracycline and erythromycin was found in 83.0% of 23F isolates.

Among non-serotypeable isolates 76.0% had reduced susceptibility and 4.0% showed complete resistance to penicillin.

Ten years after introduction of 7vPCV for Aboriginal Australian children, 7vPCV serotypes account for a small proportion of carried pneumococci.

A large proportion of circulating serotypes are not covered by any currently licensed vaccine.