Journal Article

Indirect (herd) protection, following pneumococcal conjugated vaccines introduction: A systematic review of the literature

Ben-Shimol, Shalom, Tsaban, Gal

2017

نظرة عامة

•This is a systemic literature review on PCV indirect (herd) impact in adults.•Adults IPD and pneumonia rates decreased in most countries post-PCV introduction.•Herd protection depended on PCV uptake rates and time from PCV implementation.•Adults >65years old seem to benefit the most from PCV introduction. Pneumococcal diseases are major causes of morbidity among adults, especially those over 50years of age. While pneumococcal conjugated vaccines (PCV’s) impact on pneumococcal disease rates among children is well established, the extent of its impact on adult pneumococcal related illness remains unclear. The aim of this systematic literature review was to describe the impact of PCV introduction to childhood national immunization programs worldwide on PCV-naive adult population. A systematic literature search was performed using the PubMed database. The search was limited to articles written in English and published between January 2000 and February 2016. Studies evaluating pneumococcal disease rates in individuals over 5years of age were included. Independent extraction of articles was performed by the two authors. Search terms included: Pneumococcal conjugated vaccine, herd, indirect, adults, and pneumonia. Forty-nine articles meeting the selection criteria were identified, 39 regarding invasive pneumococcal disease (IPD, one on meningitis only), 8 regarding pneumonia, and 2 on both IPD and pneumonia. The majority of reports were from the US, UK and Canada. Considerable variability in the data sources, quality and completeness was observed. While most studies reported either statistically significant reduction or insignificant changes in IPD and pneumonia disease rates in adults following PCV nationwide implementation, few studies reported statistically significant increase in pneumococcal disease rates, these were mainly from countries with low PCV coverage rates and/or inadequate surveillance. Invasive pneumococcal diseases and pneumonia rates among the adult population decreased in most countries following PCV introduction into the NIP. This indirect effect on older population seems to be dependent on PCV coverage rates and time from PCV nationwide implementation. Adults >65years old seem to benefit the most from PCV introduction.

• الناشر: Elsevier Ltd,Elsevier Limited
• موضوع: Adolescent / Adult / Adults / Age / Age Factors / Aged / Aged, 80 and over / Allergy and Immunology / Canada / Canada - epidemiology / Child / Child, Preschool / childhood / Children / Cost analysis / Disease / Epidemiology / Female / Herd protection / herds / Humans / Immunity, Herd / Immunization / Immunization Programs / Indirect immunity / Invasive pneumococcal disease (IPD) / Laboratories / Literature reviews / Male / Meningitis / Middle Aged / Morbidity / Older people / Pneumococcal conjugated vaccine (PCV) / Pneumococcal Infections - epidemiology / Pneumococcal Infections - immunology / Pneumococcal Infections - prevention & control / Pneumococcal Vaccines - administration & dosage / Pneumococcal Vaccines - immunology / Pneumonia / Pneumonia, Pneumococcal - epidemiology / Pneumonia, Pneumococcal - microbiology / Pneumonia, Pneumococcal - prevention & control / Population / selection criteria / Statistical analysis / Streptococcus infections / Streptococcus pneumoniae - immunology / Studies / Surveillance / Systematic review / United Kingdom / United States / Vaccination / Vaccines / Vaccines, Conjugate - administration & dosage / Vaccines, Conjugate - immunology / Young Adult