Measuring the effects of pneumococcal conjugate vaccine (PCV7) on Streptococcus pneumoniae carriage and antibiotic resistance: The Palestinian-Israeli Collaborative Research (PICR)

• Published in: Vaccine 2015-02, Vol.33 (8), p.1021-1026
• Main Authors: Daana, Muhannad, Rahav, Galia, Hamdan, Ayob, Thalji, Amin, Jaar, Fuad, Abdeen, Ziad, Jaber, Hanaa, Goral, Aviva, Huppert, Amit, Raz, Meir, Regev-Yochay, Gili
• Format: Article
• Language: English
• Subjects: Adolescent; Allergy and Immunology; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Antibiotic resistance; Antibiotics; Carrier State; Child; Child, Preschool; Confidence intervals; Drug resistance; Drug Resistance, Bacterial; Female; Health maintenance organizations; Health policy; HMOs; Humans; Immunization; Infant; Infant, Newborn; Laboratories; Male; Nasopharynx - immunology; Nasopharynx - microbiology; PCV7 effects; Pediatrics; Penicillin; Pneumococcal carriage; Pneumococcal Infections - drug therapy; Pneumococcal Infections - epidemiology; Pneumococcal Infections - immunology; Pneumococcal Infections - prevention & control; Pneumococcal Vaccines - immunology; Population; Population-based study; Prevalence; Serogroup; Streptococcus infections; Streptococcus pneumoniae; Streptococcus pneumoniae - classification; Streptococcus pneumoniae - drug effects; Streptococcus pneumoniae - immunology; Studies; Vaccines; Vaccines, Conjugate - immunology
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2015.01.003

Abstract Background The Palestinian-Israeli Collaborative Research (PICR) cross-conflict setting provided a unique opportunity to study overall and indirect effects of pneumococcal conjugate vaccine (PCV7), in two closely related Palestinian populations governed by two distinct health authorities with distinct vaccination policies. Here, PCV7 effects on pneumococcal carriage, serotype distribution and antibiotic resistance are reported. Methods Annual cross-sectional surveys of pneumococcal carriage were performed during 2009–2011 among Palestinian children (≤5 years) (a) under Palestinian-Authority (PA) health policy (Ramallah, Nablus and Bethlehem), where PCV7 was unlicensed (b) under Israeli health policy (East-Jerusalem (EJ)) where PCV7 was rapidly implemented from July 2009. Clinical data were collected, pneumococci identified and characterized for antibiotic susceptibilities and serotype. Analyses included multivariate logistic models with an interaction term for PCV7-effect. Results Altogether, 2755 children from PA ( n = 1772) and EJ ( n = 983) were enrolled, of which ∼30% were pneumococcal carriers. While overall carriage was not affected by vaccination policy, carriage of vaccine-type (VT7) strains decreased from 52% to 22% ( p < 0.001) in EJ, where PCV was implemented, but not in PA. This was accompanied by an increase in non-VT13 strains from 34% to 65% ( p < 0.001) in EJ, but not in PA. Furthermore, within two years post-PCV7 introduction, proportion of multi-drug resistant strains, which was initially 23% in both populations, decreased significantly in EJ, to 10%, while simultaneously it increased in PA to 33% ( p < 0.001). Similar trends were observed for resistance to most antibiotic groups. The proportion of resistant isolates among non-VT13 strains did not change during the study period. Conclusions The unique study design distinguishes secular and seasonal effects from true vaccine effects. While PCV7 did not affect overall pneumococcal carriage rate, VT7 strains, many of which were antibiotic resistant decreased and were replaced by non-VT13 strains, which were mostly not antibiotic resistant, resulting in a net decrease in antibiotic resistance.