Laura L. Hammitt, United States of America

Author Of 4 Presentations

 Conference Calendar

DIFFERENCES IN PNEUMOCOCCAL CARRIAGE PREVALENCE BY TESTING METHOD AND SPECIMEN TYPE AMONG NATIVE AMERICAN INDIVIDUALS DURING ROUTINE USE OF 13-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV13) (ID 995)

Session Name
Clinical Sciences - Pneumococcal Infections in Aboriginal Populations
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CHARACTERIZATION OF STREPTOCOCCUS PNEUMONIAE SEROTYPE 3 CARRIAGE AND DISEASE ISOLATES AMONG NATIVE AMERICANS IN THE SOUTHWEST UNITED STATES (ID 1020)

Session Name
Basic Sciences - Genomics and Transmission
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Abstract

Background

Despite inclusion in PCV13, Streptococcus pneumoniae serotype 3 (ST3) continues to cause significant morbidity and mortality. In Native American communities in the southwest US in 2015-2017, the ST3 carriage prevalence among children was 2.7% and the incidence of ST3 invasive pneumococcal disease (IPD) among adults was 9.0/100,000. An emerging lineage of ST3 belonging to Clonal Complex (CC) 180, termed clade II, has recently increased.

Methods

We analyzed the genomic epidemiology of 202 ST3 isolates collected from 133 adults and 69 children with carriage (n=71) or IPD (n=131) from 1999–2018. Using phylogenetics based on whole-genome sequencing data, we determined clade membership of each isolate and assessed how the population structure changed over time.

Results

The percent of isolates belonging to clade II increased from 22.3% (n=94) in 1999-2010 to 65.7% (n=108) in 2010-2018 (Figure A). Carriage isolates were comprised equally by three clades (CC180 clade Ia n=24 and II n=23 and non-CC180 n=24); however, IPD isolates were more likely to be clade II (1a n=37, II n=69, non-CC180 n=25; OR=2.32, 95% CI 1.27-4.25) (Figure B).

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Conclusions

Overall, we find that ST3 clade II has increased significantly since the introduction of PCV13 and is found more commonly in invasive disease compared to other clades.

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CHILDREN ADMITTED TO HOSPITAL WITH LOWER-CHEST-WALL INDRAWING PNEUMONIA IN SEVEN LOW AND MIDDLE-INCOME COUNTRIES: WHO DIED AND WHO SURVIVED? (ID 758)

Session Name
Clinical Sciences - Treatment of Pneumococcal Disease in Infants, Children/Youth, and Adults
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Abstract

Background

In 2013, to increase effective distribution of antibiotics, WHO revised treatment guidelines for childhood pneumonia with lower chest wall indrawing (LCWI) to recommend home-based-treatment with oral antibiotics rather than hospital-based management. We analysed the implications of this policy in the PERCH study, where all children were hospitalised.

Methods

In PERCH, 2113 children aged 2-59 months were admitted with LCWI pneumonia between 2011-2014 in Kenya, Zambia, South Africa, Mali, The Gambia, Bangladesh and Thailand. We analysed their mortality risk, and risk factors for mortality using logistic regression.

Results

Among cases with LCWI pneumonia, 76 (3.6%) died in hospital or within 7 days of discharge. Factors associated with fatal outcome included age (aOR 2.03 (95%CI 1.05-3.93) for infants vs older children), absence of cough, oxygen saturation (80-91% oxygen aOR 2.04 (1.07-3.90), <80% aOR 6.51 (2.82-15.0)), low anthropometric scores and HIV exposure.

Conclusions

Despite hospital admission, 3.6% of children with LCWI pneumonia died; mortality may be higher among similar children if treated in the community. Among children with LCWI pneumonia presenting to hospital, selective admission for those who also have hypoxia, features of malnutrition and young age may ensure that those with the greatest risk of death receive optimal supportive therapy.

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LONG-TERM TRENDS IN NASOPHARYNGEAL CARRIAGE OF VACCINE-TYPE PNEUMOCOCCI: FINDINGS FROM A MATURE 10-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV10) PROGRAM IN KENYA (ID 966)

Session Name
Vaccines - Impact of Vaccine programs and Serotype Replacement
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Abstract

Background

PCV10 was introduced into Kenya’s immunization program in 2011, with catchup in children aged 1-4 years. We evaluated the long-term effect of PCV10 on nasopharyngeal carriage of Streptococcus pneumoniae serotypes included in PCV10.

Methods

Population-based annual cross-sectional nasopharyngeal carriage surveys were conducted in randomly selected individuals between 2009 and 2019 (N= ~1000 in 2019; N= ~500 in all others) in Kilifi, Kenya. Pneumococcal identification was performed per WHO standards. Annual vaccine-type carriage prevalence was modelled using log-binomial regression with a curved function for year and adjustment for age-specific sampling probability.

Results

Compared to 2010, carriage of PCV10-type pneumococci declined significantly through 2019 in children aged <5 years to 6.1% (adjusted prevalence ratio 0.18, 95%CI 0.11-0.30) but not in children aged 5-14 years (prevalence= 7.1%; 0.71, 0.38-1.34) nor adults ≥15 years (prevalence= 1.0%; 0.49, 0.17-1.35). PCV10-type carriage was significantly lower in 2017 compared to 2010 for all age groups and did not differ from carriage prevalence in 2019 (figure).

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Conclusions

PCV10-type carriage prevalence appears to be approaching equilibrium, yet residual carriage persists. Virtual elimination of PCV10-type carriage (≤1% in children <5 years; ≤3% in children 5-9 years) – a prerequisite for introduction of reduced dose schedules – is unlikely without implementation of additional strategies.

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