title: Estimated Effect of Inactivated Poliovirus Vaccine Campaigns, Nigeria and Pakistan, January 2014-April 2016.
abstract: In 2014, inactivated poliovirus vaccine (IPV) campaigns were implemented in Nigeria and Pakistan after clinical trials showed that IPV boosts intestinal immunity in children previously given oral poliovirus vaccine (OPV). We estimated the effect of these campaigns by using surveillance data collected during January 2014-April 2016. In Nigeria, campaigns with IPV and trivalent OPV (tOPV) substantially reduced the incidence of poliomyelitis caused by circulating serotype-2 vaccine-derived poliovirus (incidence rate ratio [IRR] 0.17 for 90 days after vs. 90 days before campaigns, 95% CI 0.04-0.78) and the prevalence of virus in environmental samples (prevalence ratio [PR] 0.16, 95% CI 0.02-1.33). Campaigns with tOPV alone resulted in similar reductions (IRR 0.59, 95% CI 0.18-1.97; PR 0.45, 95% CI 0.21-0.95). In Pakistan, the effect of IPV+tOPV campaigns on wild-type poliovirus was not significant. Results suggest that administration of IPV alongside OPV can decrease poliovirus transmission if high vaccine coverage is achieved.
authors.forename: George
authors.initials: G
authors.lastname: Shirreff
authors.forename: Mufti Zubair
authors.initials: MZ
authors.lastname: Wadood
authors.forename: Rui Gama
authors.initials: RG
authors.lastname: Vaz
authors.forename: Roland W
authors.initials: RW
authors.lastname: Sutter
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Grassly
mesh_terms: D005260:Female; D062306:Geography, Medical; D049674:History, 21st Century; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D017063:Outcome Assessment, Health Care; D010154:Pakistan / Q000453:epidemiology; D011051:Poliomyelitis / Q000453:epidemiology* / Q000266:history / Q000517:prevention & control*; D017955:Poliovirus / Q000276:immunology*; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage / Q000276:immunology*; D015995:Prevalence; D014611:Vaccination
chemical_list: D011054:Poliovirus Vaccine, Inactivated
keywords: IPV; Nigeria; Pakistan; epidemiology; immunization; inactivated poliovirus vaccine; mass campaign; polio; poliovirus; trivalent oral polio vaccine; vaccination; vaccine campaign; vaccines; viruses