Original StudiesMeasles vaccine effectiveness in standard and early immunization strategies, Niger, 1995KANINDA, ANNE-VALÉRIE MD, MPH; LEGROS, DOMINIQUE MD, MPH; JATAOU, IDI MOUSSA MD, MPH; MALFAIT, PHILIPPE MD, MPH; MAISONNEUVE, MARC RN; PAQUET, CHRISTOPHE MD, MPH; MOREN, ALAIN MD, PHDAuthor Information From Epicentre (AVK, DL, PM, CP, AM) and Médecins Sans Frontières (MM), Paris, France; and Direction Nationale du PEV, Ministère de la Santé Publique, Niger (IMJ). Accepted for publication Aug. 14, 1998. Address for reprints: Dr. Anne-Valérie Kaninda, Epicentre, 8 rue Saint-Sabin, 75011 Paris, France. Fax 33-1-40-21-2803; E-mail firstname.lastname@example.org. The Pediatric Infectious Disease Journal: November 1998 - Volume 17 - Issue 11 - p 1034-1039 Buy Abstract Background. An Expanded Programme on Immunization was started in late 1987 in Niger, including vaccination against measles with one dose of standard titer Schwarz vaccine given to infants after 9 months of age. During epidemics an early two-dose strategy was implemented (one dose between 6 and 8 months and one dose after 9 months). From January 1, 1995, until May 7, 1995, 13 892 measles cases were reported in Niamey, Niger. Methods. A retrospective cohort study was conducted in a crowded area of Niamey at the end of the outbreak to assess the effectiveness of measles vaccine in standard (after 9 months) and early (before 9 months) immunization strategies under field conditions. Results. Highest measles incidence rates were observed among children <1 year of age. Vaccine effectiveness estimates increased with age at vaccination from 78% with a single dose administered at 6 months of age to 95% at 9 months. Vaccine effectiveness with the early two dose strategy was 93%. Conclusions. Immunization with a single dose of standard titer Schwarz vaccine before 9 months of age provided higher clinical protection than expected from seropositivity studies. The early two dose strategy is justified in contexts where measles incidence is high before 9 months of age. Our results raise the issue of lowering the recommended age for measles vaccination in developing countries. © Williams & Wilkins 1998. All Rights Reserved.