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Factors associated with pneumococcal carriage and density in children and adults in Fiji, using four cross-sectional surveys.

ABSTRACT: This study describes predictors of pneumococcal nasopharyngeal carriage and density in Fiji. We used data from four annual (2012-2015) cross-sectional surveys, pre- and post-introduction of ten-valent pneumococcal conjugate vaccine (PCV10) in October 2012. Infants (5-8 weeks), toddlers (12-23 months), children (2-6 years), and their caregivers participated. Pneumococci were detected and quantified using lytA qPCR, with molecular serotyping by microarray. Logistic and quantile regression were used to determine predictors of pneumococcal carriage and density, respectively. There were 8,109 participants. Pneumococcal carriage was negatively associated with years post-PCV10 introduction (global P<0.001), and positively associated with indigenous iTaukei ethnicity (aOR 2.74 [95% CI 2.17-3.45] P<0.001); young age (infant, toddler, and child compared with caregiver participant groups) (global P<0.001); urban residence (aOR 1.45 [95% CI 1.30-2.57] P<0.001); living with ≥2 children <5 years of age (aOR 1.42 [95% CI 1.27-1.59] P<0.001); low family income (aOR 1.44 [95% CI 1.28-1.62] P<0.001); and upper respiratory tract infection (URTI) symptoms (aOR 1.77 [95% CI 1.57-2.01] P<0.001). Predictors were similar for PCV10 and non-PCV10 carriage, except PCV10 carriage was negatively associated with PCV10 vaccination (0.58 [95% CI 0.41-0.82] P = 0.002) and positively associated with exposure to household cigarette smoke (aOR 1.21 [95% CI 1.02-1.43] P = 0.031), while there was no association between years post-PCV10 introduction and non-PCV10 carriage. Pneumococcal density was positively associated with URTI symptoms (adjusted median difference 0.28 [95% CI 0.16, 0.40] P<0.001) and toddler and child, compared with caregiver, participant groups (global P = 0.008). Predictors were similar for PCV10 and non-PCV10 density, except infant, toddler, and child participant groups were not associated with PCV10 density. PCV10 introduction was associated with reduced the odds of overall and PCV10 pneumococcal carriage in Fiji. However, after adjustment iTaukei ethnicity was positively associated with pneumococcal carriage compared with Fijians of Indian Descent, despite similar PCV10 coverage rates.

SUBMITTER: Neal EFG

PROVIDER: S-EPMC7112956 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundThe indirect effects of pneumococcal conjugate vaccines (PCVs) are mediated through reductions in carriage of vaccine serotypes. Data on PCVs in Asia and the Pacific are scarce. Fiji introduced the ten-valent PCV (PCV10) in 2012, with a schedule consisting of three priming doses at 6, 10, and 14 weeks of age and no booster dose (3 + 0 schedule) without catch-up. We investigated the effects of PCV10 introduction using cross-sectional nasopharyngeal carriage surveys.MethodsWe did four annual carriage surveys (one pre-PCV10 and three post-PCV10) in the greater Suva area in Fiji, during 2012-15, of 5-8-week-old infants, 12-23-month-old children, 2-6-year-old children, and their caregivers (total of 8109 participants). Eligible participants were of appropriate age, had axillary temperature lower than 37°C, and had lived in the community for at least 3 consecutive months. We used purposive quota sampling to ensure a proper representation of the Fiji population. Pneumococci were detected by real-time quantitative PCR, and molecular serotyping was done with microarray.Findings3 years after PCV10 introduction, vaccine-serotype carriage prevalence declined, with adjusted prevalences (2015 vs 2012) of 0·56 (95% CI 0·34-0·93) in 5-8-week-old infants, 0·34 (0·23-0·49) in 12-23-month-olds, 0·47 (0·34-0·66) in 2-6-year-olds, and 0·43 (0·13-1·42) in caregivers. Reductions in PCV10 serotype carriage were evident in both main ethnic groups in Fiji; however, carriage of non-PCV10 serotypes increased in Indigenous Fijian infants and children. Density of PCV10 serotypes and non-PCV10 serotypes was lower in PCV10-vaccinated children aged 12-23 months than in PCV10-unvaccinated children of the same age group (PCV10 serotypes -0·56 [95% CI -0·98 to -0·15], p=0·0077; non-PCV10 serotypes -0·29 [-0·57 to -0·02], p=0·0334).InterpretationDirect and indirect effects on pneumococcal carriage post-PCV10 are likely to result in reductions in pneumococcal disease, including in infants too young to be vaccinated. Serotype replacement in carriage in Fijian children, particularly Indigenous children, warrants further monitoring. Observed changes in pneumococcal density might be temporal rather than vaccine related.FundingDepartment of Foreign Affairs and Trade of the Australian Government through the Fiji Health Sector Support Program; Victorian Government's Operational Infrastructure Support Program; Bill & Melinda Gates Foundation.

Project description:BackgroundIn the first 2 years after a nationwide mass vaccination campaign of 1-29-year-olds with a meningococcal serogroup A conjugate vaccine (MenAfriVac) in Burkina Faso, carriage and disease due to serogroup A Neisseria meningitidis were nearly eliminated. We aimed to assess the long-term effect of MenAfriVac vaccination on meningococcal carriage and herd immunity.MethodsWe did four cross-sectional studies of meningococcal carriage in people aged 9 months to 36 years in two districts of Burkina Faso between May 2, 2016, and Nov 6, 2017. Demographic information and oropharyngeal swabs were collected. Meningococcal isolates were characterised using whole-genome sequencing.FindingsOf 14 295 eligible people, 13 758 consented and had specimens collected and laboratory results available, 1035 of whom were meningococcal carriers. Accounting for the complex survey design, prevalence of meningococcal carriage was 7·60% (95% CI 5·67-9·52), including 6·98% (4·86-9·11) non-groupable, 0·48% (0·01-0·95) serogroup W, 0·10% (0·01-0·18) serogroup C, 0·03% (0·00-0·80) serogroup E, and 0% serogroup A. Prevalence ranged from 5·44% (95% CI 4·18-6·69) to 9·14% (6·01-12·27) by district, from 4·67% (2·71-6·64) to 11·17% (6·75-15·59) by round, and from 3·39% (0·00-8·30) to 10·43% (8·08-12·79) by age group. By clonal complex, 822 (88%) of 934 non-groupable isolates were CC192, all 83 (100%) serogroup W isolates were CC11, and nine (69%) of 13 serogroup C isolates were CC10217.InterpretationOur results show the continued effect of MenAfriVac on serogroup A meningococcal carriage, for at least 7 years, among vaccinated and unvaccinated cohorts. Carriage prevalence of epidemic-prone serogroup C CC10217 and serogroup W CC11 was low. Continued monitoring of N meningitidis carriage will be crucial to further assess the effect of MenAfriVac and inform the vaccination strategy for future multivalent meningococcal vaccines.FundingBill & Melinda Gates Foundation and Gavi, the Vaccine Alliance.

Project description:BACKGROUND:Streptococcus pneumoniae carriage is often asymptomatic but can cause invasive pneumococcal disease. Pneumococcal carriage is a prerequisite for disease, with children as main reservoir and transmitters. Childhood carriage can therefore be used to determine which serotypes circulate in the population and which may cause disease in the non-vaccinated population. In 2006, a pneumococcal conjugate vaccine (PCV7) was introduced into the Norwegian Childhood Immunisation Programme, which was replaced by the more valent PCV13 in 2011. We investigated changes in pneumococcal carriage prevalence 4 years after switching to PCV13 compared to three previous surveys, and analysed factors associated with carriage in children. METHODS:We conducted a cross-sectional study in Norway, autumn 2015, among children attending day-care centres. We collected questionnaire data and nasopharyngeal swabs to identify pneumococcal serotypes. We compared the carriage prevalence in 2015 with surveys conducted in the same setting performed before widespread vaccination (2006; n = 610), 2 years after PCV7 introduction (2008; n = 600), and 2 years after switching to PCV13 (2013; n = 874). Using multilevel logistic regression we determined the association between pneumococcal carriage and previously associated factors. RESULTS:In 2015, 896 children participated, with age ranging from 8 to 80 months. The overall carriage prevalence was 48/100 children [95%CI 44-53] in 2015, 38% [29-46] lower than in 2006 pre-PCV7, and 23% [12-32] lower than in 2013, 2 years after switching to PCV13. The PCV13 carriage prevalence was 2.8/100 children [1.9-4.2] in 2015. Increasing age (p < 0.001), recent antimicrobial use (odds ratio = 0.42 [0.21-0.57]) and being vaccinated (odds ratio = 0.37 [0.29-0.47]) were negatively associated with carriage. CONCLUSIONS:Our study showed a continued decrease in overall pneumococcal carriage, mainly fuelled by the decline in vaccine serotypes after vaccine introduction. Childhood vaccination with PCV13 should be continued to keep low PCV13 carriage, transmission and disease. Furthermore, the low prevalence of PCV13-type carriage in children endorse the choice of not recommending PCV13 in addition to the 23-valent pneumococcal polysaccharide vaccine to most medical risk groups in Norway, as little disease caused by these serotypes can be expected.

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Factors associated with pneumococcal carriage and density in children and adults in Fiji, using four cross-sectional surveys.

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