Long-term Immunogenicity of Measles Vaccine: An Italian Retrospective Cohort Study

J Infect Dis. 2020 Feb 18;221(5):721-728. doi: 10.1093/infdis/jiz508.


Background: Levels of antibodies induced by the measles virus-containing vaccine have been shown to decline over time, but there is no formal recommendation about testing immunized subjects (in particular, healthcare workers [HCWs]) to investigate the persistence of measles immunoglobulin G (IgG).

Methods: This study aims to evaluate the long-term immunogenicity of measles vaccine in a sample of medical students and residents of the University of Bari who attended the Hygiene Department for a biological risk assessment (April 2014-June 2018).

Results: Two thousand immunized (2 doses of measles-mumps-rubella [MMR] vaccine) students and residents were tested; 305 of these (15%) did not show protective anti-measles IgG. This proportion was higher among subjects who received vaccination at ≤15 months (20%) than in those who received vaccination at 16-23 months (17%) and at ≥24 months (10%) (P < .0001). After an MMR vaccine booster dose, we noted a seroconversion of 74% of seronegative HCWs. The overall seroconversion rate after a second dose (booster) was 93%. No serious adverse events were noted after the booster doses.

Conclusions: An important proportion of subjects immunized for measles do not show a protective IgG titer in the 10 years after vaccination. Our management strategy seems consistent with the purpose of evidencing immunological memory.

Keywords: healthcare workers; booster dose; duration of immunization.

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Viral / blood
  • Antibodies, Viral / immunology
  • Female
  • Humans
  • Immunization Schedule
  • Immunogenicity, Vaccine*
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Italy
  • Male
  • Measles / prevention & control*
  • Measles / virology
  • Measles-Mumps-Rubella Vaccine / immunology*
  • Morbillivirus / immunology*
  • Mumps / prevention & control*
  • Mumps / virology
  • Mumps virus / immunology*
  • Retrospective Studies
  • Rubella / prevention & control*
  • Rubella / virology
  • Rubella virus / immunology*
  • Vaccination*
  • Young Adult


  • Antibodies, Viral
  • Immunoglobulin G
  • Measles-Mumps-Rubella Vaccine