title: Persistence of measles antibodies, following changes in the recommended age for the second dose of MMR-vaccine in Portugal.
abstract: In populations vaccinated with two doses of combined measles-mumps-rubella vaccine (MMR), the serum levels of antibodies against measles depend on the vaccination schedule, time elapsed from the last dose and the area-specific epidemiological situation. Variables measuring "schedule" are age at first and second doses of MMR and intervals derived from that. Changes in vaccination schedules have been made in Portugal. The specific objectives of this study were to measure the association between those potential determinants and the concentration of measles-specific IgG antibodies, after the second dose of MMR. Convenience samples of three Portuguese birth cohorts were selected for this study (41, 66 and 60 born, respectively, in 2001-2003, 1990-1993 and 1994-1995). Geometric mean concentrations (GMC) for measles IgG were, respectively, 934, 251 and 144mIU/ml; p<0.001). Anti-measles-IgG serum concentration decreased with time since last vaccination (waning immunity) and was not influenced by any other component of vaccination schedule, namely age at vaccination with the second dose of MMR. Waning levels of measles antibodies have been observed elsewhere but not as fast as it was observed in Portuguese birth cohorts in this study. Changes in the vaccination schedules might have to be considered in the future.
authors: Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto Rua de Jorge Viterbo Ferreira, no. 228, Porto 4050-313, Portugal; Unit for Multidisciplinary Biomedical Research (UMIB) Rua de Jorge Viterbo Ferreira, no 228, Porto 4050-313, Portugal. Electronic address: aggoncalves@icbas.up.pt.
authors: Guilherme
authors: G
authors: Gonçalves
authors: School of Health Sciences, Polytechnic Institute of Leiria Campus 2 - Morro do Lena - Alto do Vieiro, Apartado 4137, Leiria 2411-901, Portugal; National School of Public Health, Universidade Nova de Lisboa Avenida Padre Cruz, Lisboa 1600-560, Portugal. Electronic address: joao.frade@ipleiria.pt.
authors: João
authors: J
authors: Frade
authors: National School of Public Health, Universidade Nova de Lisboa Avenida Padre Cruz, Lisboa 1600-560, Portugal; Centro de Investigação em Saúde Pública (CISP) Avenida Padre Cruz, Lisboa 1600-560, Portugal. Electronic address: CNunes@ensp.unl.pt.
authors: Carla
authors: C
authors: Nunes
authors: Agrarian Superior School, Polytechnic Institute of Viseu Quinta da Alagoa - Estrada de Nelas, Ranhados, Viseu 3500-606, Portugal. Electronic address: jmesquita@outlook.com.
authors: João Rodrigo
authors: JR
authors: Mesquita
authors: Laboratory of Microbiology, Department of Biological Sciences, Faculty of Pharmacy of University of Porto Rua de Jorge Viterbo Ferreira, no. 228, Porto 4050-313, Portugal. Electronic address: saojose@ff.up.pt.
authors: Maria São José
authors: MS
authors: Nascimento
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008457:Measles / Q000517:prevention & control*; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D011174:Portugal; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D022542:Measles-Mumps-Rubella Vaccine
keywords: Antibodies; Immunisation; Measles; Measles–mumps–rubella (MMR) vaccine; Vaccination schedule