Mumps outbreak among fully vaccinated school-Age children and young adults, Portugal 2019/2020

Mariana Perez Duque*, Ana San-Bento, Lourdes Léon, Paula Custódio, Maria Anjos Esperança, Maria João Albuquerque, Marina Nascimento, Sooria Balasegaram, Rita Sá Machado

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)
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    On 16-17 January 2020, four suspected mumps cases were reported to the local Public Health Authorities with an epidemiological link to a local school and football club. Of 18 suspected cases identified, 14 were included in this study. Laboratory results confirmed mumps virus as the cause and further sequencing identified genotype G. Our findings highlight that even with a high MMR vaccine coverage, mumps outbreaks in children and young adults can occur. Since most of the cases had documented immunity for mumps, we hypothesise that waning immunity or discordant mumps virus strains are likely explanations for this outbreak.

    Original languageEnglish
    Article number205
    Number of pages3
    JournalEpidemiology and Infection
    Publication statusPublished - 27 Aug 2021

    Bibliographical note

    Funding Information: The authors did not receive support from any organisation for the submitted work.

    Open Access: This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided that no alterations are made and the original article is properly cited. The written permission of Cambridge University Press must be obtained prior to any commercial use and/or adaptation of the article.

    Publisher Copyright: © The Author(s), 2021. Published by Cambridge University Press

    Citation: Duque, Mariana Perez, et al. "Mumps outbreak among fully vaccinated school-age children and young adults, Portugal 2019/2020." Epidemiology & Infection 149 (2021).



    • Key words MMR vaccination
    • Mumps
    • Outbreaks
    • Vaccine preventable diseases
    • Virology


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