Pneumococcal carriage in rural Gambia prior to the introduction of pneumococcal conjugate vaccine: a population‐based survey

Abstract

Abstractobjective To evaluate pneumococcal colonisation before and after the introduction of pneumococcal conjugate vaccine (PCV) in eastern Gambia. results The prevalence of nasopharyngeal pneumococcal carriage in 2933 individuals was 72.0% in underfives (N = 515), 41.6% in children aged 5-17 (N = 1508) and 13.0% in adults ≥18 (N = 910) years. The age-specific prevalence of serotypes included in PCV7, PCV10 and PCV13 was 24.7%, 26.6% and 46.8% among children <5 years of age; 8.5%, 9.2% and 17.7% among children 5-17 years; and 2.5%, 3.3% and 5.5% among adults ≥18 years. The most common serotypes were 6A

Pneumococcal nasopharyngeal carriage in children <5 years of age visiting the pediatric emergency room in relation to PCV7 and PCV13 introduction in southern Israel

“…22,23 In contrast to the impressive impact of PCVs on different pneumococcal diseases, with the potential of rapidly achieving near eradication of vaccine serotype disease in the vaccinated age group, 3,14 vaccine impact on overall pneumococcal carriage was less prominent. [8][9][10] This lesser effect was observed in many studies, 6,7,19,24 however, over time, vaccine impact on VT-carriage reached a magnitude similar to that observed with IPD. 10,19 In contrast to IPD, replacement of NP carriage of VT serotype by non-VT serotypes occurred rapidly and extensively, leading to increased colonization and transmission of non-VT strains.…”

“…[8][9][10] This lesser effect was observed in many studies, 6,7,19,24 however, over time, vaccine impact on VT-carriage reached a magnitude similar to that observed with IPD. 10,19 In contrast to IPD, replacement of NP carriage of VT serotype by non-VT serotypes occurred rapidly and extensively, leading to increased colonization and transmission of non-VT strains. 10,19,25 The 13-valent pneumococcal conjugate vaccine (PCV13) introduction resulted in lower acquisition and prevalence of NP colonization than the 7-valent pneumococcal conjugate vaccine (PCV7) for the majority of additional PCV13 serotypes as well as serotypes 6C and 19F, and it was comparable to PCV7 with regard to all other common serotypes.…”

“…Despite a marked reduction in VT13 serotype carriage, the impact of PCVs on all-pneumococcal carriage is less pronounced than that observed for IPD and other pneumococcal diseases. [8][9][10] This lesser effect was observed mainly due to the increase of non-PCV13 serotypes carriage, replacing vaccine-serotypes carriage. This replacement in the NP niche was reported to occur rapidly and extensively, leading to increased colonization and transmission of non-VT strains.…”

“…7 Pneumococcal NP carriage rates vary in different settings worldwide. [8][9][10] This variation may derive, at least in part, from demographic, ethnical and cultural differences, with higher carriage rates observed in populations suffering from poverty, over-crowding, exposure to smoking and poor hygienic conditions, [10][11][12] as well as history of breast feeding, day-care center attendance and antibiotic treatment at the individual and societal levels. 7 The introduction of the pneumococcal conjugate vaccines (PCVs) to the national immunization plans (NIP) worldwide resulted in substantial rate reductions of various pneumococcal disease end-points, including invasive pneumococcal disease (IPD), 13,14 pneumonia, [15][16][17][18] and otitis media, 3 including unvaccinated age groups and individuals.…”

“…10,19 In contrast to IPD, replacement of NP carriage of VT serotype by non-VT serotypes occurred rapidly and extensively, leading to increased colonization and transmission of non-VT strains. 10,19,25 The 13-valent pneumococcal conjugate vaccine (PCV13) introduction resulted in lower acquisition and prevalence of NP colonization than the 7-valent pneumococcal conjugate vaccine (PCV7) for the majority of additional PCV13 serotypes as well as serotypes 6C and 19F, and it was comparable to PCV7 with regard to all other common serotypes. 1,25 Further beneficial impact of PCVs, beyond reduction of disease and carriage rates was reduction in antibiotic use and in pneumococcal antibiotic resistance.…”