Using pneumococcal carriage studies to monitor vaccine impact in low- and middle-income countries

Chan, Jocelyn; Nguyen, Cattram; Dunne, Eileen M.; Mulholland, E. Kim; Mungun, Tuya; Pomat, William; Rafai, Eric; Satzke, Catherine; Weinberger, Daniel M.; Russell, Fiona M.

doi:10.1016/j.vaccine.2019.08.073

Cited by 34 publications

(40 citation statements)

References 85 publications

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“…9 An alternative approach for assessing PCV impact is using surveillance of nasopharyngeal (NP) pneumococcal carriage. 10 Pneumococcal carriage is common and generally asymptomatic. 5 It is the primary means of pneumococcal transmission and a prerequisite for invasive disease.…”

Section: Introductionmentioning

confidence: 99%

“…5 PCVs reduce carriage of VTs in the nasopharynx among vaccinated individuals, thereby reducing transmission and providing indirect effects to both vaccinated and non-vaccinated individuals. 10 It is often assumed that high PCV coverage is required to interrupt VT pneumococcal transmission and achieve substantial indirect effects (or indeed the elimination of VT pneumococcal disease), since near-elimination has predominantly been demonstrated in countries with greater than 90% vaccine coverage. 8 However, two observational studies from the USA suggest that statistically significant indirect effects against pneumococcal VT carriage can be achieved at 58%-75% coverage among children under 5 years of age, 11 12 but evidence from LMICs are lacking.…”

Section: Introductionmentioning

confidence: 99%

“…13 Furthermore, baseline data for comparisons pre-PCV and post-PCV may not always be available. 10 In recognition of these limitations, a study from Bangladesh used a novel approach to assess the indirect effects of cholera vaccine which compared the rates of cholera in communities with varying levels of vaccine coverage. 14 For this study, we adapted these methods to evaluate the direct and indirect effects of PCV.…”

Section: Introductionmentioning

confidence: 99%

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Indirect effects of 13-valent pneumococcal conjugate vaccine on pneumococcal carriage in children hospitalised with acute respiratory infection despite heterogeneous vaccine coverage: an observational study in Lao People’s Democratic Republic

et al. 2021

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IntroductionEmpiric data on indirect (herd) effects of pneumococcal conjugate vaccines (PCVs) in settings with low or heterogeneous PCV coverage are limited. The indirect effects of PCV, which benefits both vaccinated and non-vaccinated individuals, are mediated by reductions in vaccine-type (VT) carriage (a prerequisite for disease). The aim of this study among hospitalised children in Lao People’s Democratic Republic (Lao PDR) is to determine the effectiveness of a 13-valent PCV (PCV13) against VT pneumococcal nasopharyngeal carriage (direct effects) and the association between village-level PCV13 coverage and VT carriage (indirect effects).MethodsPneumococcal nasopharyngeal carriage surveillance commenced in December 2013, shortly after PCV13 introduction (October 2013). We recruited and swabbed children aged 2–59 months admitted to hospital with acute respiratory infection. Pneumococci were detected using lytA quantitative real-time PCR and serotyped using microarray. PCV13 status and village-level PCV13 coverage were determined using written immunisation records. Associations between both PCV13 status and village-level PCV13 coverage and VT carriage were calculated using generalised estimating equations, controlling for potential confounders.ResultsWe enrolled 1423 participants and determined PCV13 coverage for 368 villages (269 863 children aged under 5 years). By 2017, median village-level vaccine coverage reached 37.5%, however, the IQR indicated wide variation among villages (24.1–56.4). Both receipt of PCV13 and the level of PCV13 coverage were independently associated with a reduced odds of VT carriage: adjusted PCV13 effectiveness was 38.1% (95% CI 4.1% to 60.0%; p=0.032); and for each per cent increase in PCV13 coverage, the estimated odds of VT carriage decreased by 1.1% (95% CI 0.0% to 2.2%; p=0.056). After adjustment, VT carriage decreased from 20.0% to 12.8% as PCV13 coverage increased from zero to 60% among under 5.ConclusionsDespite marked heterogeneity in PCV13 coverage, we found evidence of indirect effects in Lao PDR. Individual vaccination with PCV13 was effective against VT carriage.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Indirect effects of 13-valent pneumococcal conjugate vaccine on pneumococcal carriage in children hospitalised with acute respiratory infection despite heterogeneous vaccine coverage: an observational study in Lao People’s Democratic Republic

et al. 2021

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“…In fact, the paucity of such studies and the need for pneumococcal carriage surveillance in Malaysia has been clearly highlighted [64]. Pneumococcal surveillance programmes are not only needed to assess the pneumococcal burden and the progress of immunisation initiative but also alerts the health bodies and scientific community on changes in serotype distribution and offers a view into herd immunity effects in the population [64][65][66][67]. The implementation of a pneumococcal surveillance programme is vital for the understanding of pneumococcal population dynamics in Malaysia, especially in children under five years of age as we are now into the post-PCV era following implementation of PCV10 into the routine NIP [16].…”

Section: Discussionmentioning

confidence: 99%

Serotype distribution of invasive, non-invasive and carried Streptococcus pneumoniae in Malaysia: a meta-analysis

Lister

Cheah

et al. 2021

Pneumonia

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Background Pneumococcal pneumonia is the leading cause of under-five mortality globally. The surveillance of pneumococcal serotypes is therefore vital for informing pneumococcal vaccination policy and programmes. Pneumococcal conjugate vaccines (PCVs) have been available as an option in the private healthcare setting and beginning December 2020, PCV10 was incorporated as part of routine national immunisation programme (NIP) in Malaysia. We searched existing literature on pneumococcal serotype distribution across Malaysia to provide an overall view of this distribution before the implementation of PCV10. Methods Online databases (PubMed, Ovid MEDLINE and Scopus), reference lists of articles identified, and grey literature (Malaysian Ministry of Health website, WHO website) were systematically searched for relevant literature on pneumococcal serotype distribution across Malaysia up to 10th November 2020. No lower date limit was set to maximise the number of target reports returned. Results of serotypes were split by age categories, including ≤5 years, > 5 years and unreported for those that did not specify. Results The search returned 18 relevant results, with a total of 2040 isolates. The most common serotypes across all disease types were 19F (n = 313, 15.3% [95%CI: 13.8–17.0]), 23F (n = 166, 8.1% [95%CI: 7.0–9.4]), 14 (n = 166, 8.1% [95%CI: 7.0–9.4]), 6B (n = 163, 8.0% [95%CI: 6.9–9.2]) and 19A (n = 138, 6.8% [95%CI: 5.8–7.9]). Conclusion Four of the most common serotypes across all isolate sources in Malaysia are covered by PCV10, while PCV13 provides greater serotype coverage in comparison to PCV10. There is still a need for surveillance studies, particularly those investigating serotypes in children under 5 years of age, to monitor vaccine effectiveness and pneumococcal population dynamic following implementation of PCV10 into routine immunisation.

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“…Carriage studies are used to measure direct and indirect effects of pneumococcal vaccination in a population, particularly in low- or middle-income settings that lack robust disease surveillance systems ( 10 ). In children, pneumococci are primarily found in the nasopharynx, and so carriage is normally determined by testing nasopharyngeal (NP) swab specimens ( 11 , 12 ).…”

Section: Introductionmentioning

confidence: 99%

The Challenges of Using Oropharyngeal Samples To Measure Pneumococcal Carriage in Adults

Boelsen

Dunne

Gould

et al. 2020

mSphere

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Streptococcus pneumoniae (the pneumococcus) carriage is commonly used to measure effects of pneumococcal vaccines. Based on findings from culture-based studies, the World Health Organization recommends both nasopharyngeal (NP) and oropharyngeal (OP) sampling for detecting adult carriage. Given evidence of potential confounding by other streptococci, we evaluated molecular methods for pneumococcal identification and serotyping from 250 OP samples collected from adults in Fiji, using paired NP samples for comparison. Samples were screened using lytA quantitative PCR (qPCR), as well as pneumococcal identification and serotyping conducted by DNA microarray. A subset of OP samples were characterized by latex sweep agglutination and multiplex PCR. Alternate qPCR assays (piaB and bguR) for pneumococcal identification were evaluated. The lytA qPCR was less specific and had poor positive predictive value (PPV) in OP samples (88% and 26%, respectively) compared with NP samples (95% and 64%, respectively). Using additional targets piaB and/or bguR improved qPCR specificity in OP, although the PPV (42 to 53%) was still poor. Using microarray, we found that 102/107 (95%) of OP samples contained nonpneumococcal streptococci with partial or divergent complements of pneumococcal capsule genes. We explored 91 colonies isolated from 11 OP samples using various techniques, including multiplex PCR, latex agglutination, and microarray. We found that nonpneumococcal streptococci contribute to false positives in pneumococcal serotyping and may also contribute to spurious identification by qPCR. Our results highlight that molecular approaches should include multiple loci to minimize false-positive results when testing OP samples. Regardless of method, pneumococcal identification and serotyping results from OP samples should be interpreted with caution. IMPORTANCE Streptococcus pneumoniae (the pneumococcus) is a significant global pathogen. Accurate identification and serotyping are vital. In contrast with World Health Organization recommendations based on culture methods, we demonstrate that pneumococcal identification and serotyping with molecular methods are affected by sample type. Results from oropharyngeal samples from adults were often inaccurate. This is particularly important for assessment of vaccine impact using carriage studies, particularly in low- and middle-income countries where there are significant barriers for disease surveillance.

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Using pneumococcal carriage studies to monitor vaccine impact in low- and middle-income countries

Cited by 34 publications

References 85 publications

Indirect effects of 13-valent pneumococcal conjugate vaccine on pneumococcal carriage in children hospitalised with acute respiratory infection despite heterogeneous vaccine coverage: an observational study in Lao People’s Democratic Republic

Indirect effects of 13-valent pneumococcal conjugate vaccine on pneumococcal carriage in children hospitalised with acute respiratory infection despite heterogeneous vaccine coverage: an observational study in Lao People’s Democratic Republic

Serotype distribution of invasive, non-invasive and carried Streptococcus pneumoniae in Malaysia: a meta-analysis

The Challenges of Using Oropharyngeal Samples To Measure Pneumococcal Carriage in Adults

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