Incidence of Pneumococcal Pneumonia Among Adults in Rural Thailand, 2006-2011: Implications for Pneumococcal Vaccine Considerations.

Barameht Piralam,Matthew R Moore,Charung Muangchana,Somrak Chantra,Peera Areerat,Sathapana Naorat,Sara M Tomczyk,Julia C Rhodes,Prabda Praphasiri,Cameron P Hurst,Sonja J Olsen,Christopher J Gregory,Henry C Baggett,Somsak Thamthitiwat,Pongpun Sawatwong

doi:10.4269/ajtmh.15-0429

Barameht Piralam, Matthew R Moore + Show 13 more

Open Access

https://doi.org/10.4269/ajtmh.15-0429

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Abstract

The incidence of pneumococcal pneumonia among adults is a key driver for the cost-effectiveness of pneumococcal conjugate vaccine used among children. We sought to obtain more accurate incidence estimates among adults by including results of pneumococcal urine antigen testing (UAT) from population-based pneumonia surveillance in two Thai provinces. Active surveillance from 2006 to 2011 identified acute lower respiratory infection (ALRI)–related hospital admissions. Adult cases of pneumococcal pneumonia were defined as hospitalized ALRI patients aged ≥ 18 years with isolation of Streptococcus pneumoniae from blood or with positive UAT. Among 39,525 adult ALRI patients, we identified 481 pneumococcal pneumonia cases (105 by blood culture, 376 by UAT only). Estimated incidence of pneumococcal pneumonia hospitalizations was 30.5 cases per 100,000 persons per year (2.2 and 28.3 cases per 100,000 persons per year by blood culture and UAT, respectively). Incidence varied between 22.7 in 2007 and 43.5 in 2010, and increased with age to over 150 per 100,000 persons per year among persons aged ≥ 70 years. Viral coinfections including influenza A/B, respiratory syncytial virus (RSV), and adenovirus occurred in 11% (44/409) of pneumococcal pneumonia cases tested. Use of UAT to identify cases of pneumococcal pneumonia among adults in rural Thailand substantially increases estimates of pneumococcal pneumonia burden, thereby informing cost-effectiveness analyses and vaccine policy decisions.

Highlights

Pneumonia is a leading cause of morbidity and mortality worldwide,[1] with an estimated 120 million episodes and 1.3 million fatalities among children.[2,3] Streptococcus pneumoniae is the most common vaccine-preventable bacterial etiology of pneumonia, causing approximately 18% of cases in children globally.[2]
Among 10,746 acute lower respiratory infection (ALRI) patients enrolled in the etiology study, 411 (3.8%) had laboratory-confirmed pneumococcal pneumonia, including 35 confirmed by blood culture and 376 by urine antigen testing (UAT) only; 20 (4.9%) of 411 were confirmed by both tests
When limited to the 6,093 ALRI patients with blood culture and UAT performed, 35 had pneumococcal pneumonia confirmed by blood culture while 225 had positive UAT only, resulting in 6.4 cases of non-bacteremic pneumococcal pneumonia for every bacteremic case

Summary

Introduction

Pneumonia is a leading cause of morbidity and mortality worldwide,[1] with an estimated 120 million episodes and 1.3 million fatalities among children.[2,3] Streptococcus pneumoniae (pneumococcus) is the most common vaccine-preventable bacterial etiology of pneumonia, causing approximately 18% of cases in children globally.[2]. Pneumococcal pneumonia is a leading cause of morbidity and mortality among adults.[8,10,11] PCV use among children prevents acquisition of vaccine-type pneumococci, reducing transmission to other children and adults.[12,13] Most countries with widespread PCV use in children have seen substantially reduced rates of IPD and pneumonia among adults, a group not targeted for vaccination.[8,12,14,15] herd effects among adults are the major drivers of cost-effectiveness estimates when considering PCV recommendations for children

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