Immune status of health care workers to measles virus: evaluation of protective titers in four measles IgG EIAs

J Clin Virol. 2015 Aug:69:214-8. doi: 10.1016/j.jcv.2015.06.095. Epub 2015 Jun 24.

Abstract

Background: Following the recognition of a measles case in a hospital in The Netherlands, health care workers (HCW) from the premises were screened by a commercial enzyme immunoassay (EIA) for measles IgG to identify persons at risk for measles. At least 10% of the HCW were tested measles IgG-negative. As this was considered an unusually high proportion, we hypothesized suboptimal sensitivity of EIAs, especially in medical personnel that had vaccine-induced immunity rather than antibodies resulting from natural infection.

Objectives: To determine (vaccine-induced) measles immunity in HCW, using different EIAs compared to the plaque reduction neutralization (PRN) test, the best surrogate marker for vaccine efficacy and immune protection.

Study design: Sera from HCW were tested for measles IgG antibodies in three commercial EIAs, in a bead-based multiplex immunoassay (MIA) and in the PRN test, and evaluated against age and vaccination history of the HCW.

Results: Of the 154 HCW, born between 1960 and 1995, 153 (99.4%) had protective levels of measles antibodies (PRN> 120mIU/ml). The three EIAs failed to detect any measles IgG antibodies in approximately 10% of the HCW, while this percentage was approximately 3% for the MIA. Negative IgG results rose to 19% for individuals born between 1975 and 1985, pointing to an age group largely representing vaccinated persons from the first measles vaccination period in The Netherlands.

Conclusion: The results show limitations in the usefulness of current EIA assays for determining protective measles antibodies in persons with a vaccination history.

Keywords: Antibody; Health care worker; Measles; Neutralization; Protection; Vaccination.

MeSH terms

  • Adult
  • Age Factors
  • Antibodies, Viral / blood*
  • Female
  • Health Personnel* / statistics & numerical data
  • Humans
  • Immunoenzyme Techniques / methods*
  • Immunoglobulin G / blood*
  • Infant
  • Male
  • Measles / blood
  • Measles / immunology*
  • Measles / prevention & control
  • Measles Vaccine / therapeutic use
  • Measles virus / immunology
  • Measles virus / isolation & purification
  • Middle Aged
  • Netherlands
  • Neutralization Tests
  • Young Adult

Substances

  • Antibodies, Viral
  • Immunoglobulin G
  • Measles Vaccine