Veille documentaire MTPH

Auteur     Susan J. M. Hahné
Auteur     Laura M. Nic Lochlainn
Auteur     Nathalie D. van Burgel
Auteur     Jeroen Kerkhof
Auteur     Jussi Sane
Auteur     Kioe Bing Yap
Auteur     Rob S. van Binnendijk
Volume     214
Numéro     12
Pages     1980-1986
Publication     The Journal of Infectious Diseases
ISSN     1537-6613
Date     Dec 15, 2016
Résumé     BACKGROUND: We investigated a measles outbreak among healthcare workers (HCWs) by assessing laboratory characteristics, measles vaccine effectiveness, and serological correlates for protection. METHODS: Cases were laboratory-confirmed measles in HCWs from hospital X during weeks 12-20 of 2014. We assessed cases’ severity and infectiousness by using a questionnaire. We tested cases’ sera for measles immunoglobulin M, immunoglobulin G, avidity, and plaque reduction neutralization (PRN). Throat swabs and oral fluid samples were tested by quantitative polymerase chain reaction. We calculated attack rates (ARs) by vaccination status and estimated measles vaccine effectiveness as 1 – [ARvaccinated/ARunvaccinated]. RESULTS: Eight HCWs were notified as measles cases; 6 were vaccinated with measles vaccine twice, 1 was vaccinated once, and 1 was unvaccinated. All 6 twice-vaccinated cases had high avidity and PRN titers. None reported severe measles or onward transmission. Two of 4 investigated twice-vaccinated cases had pre-illness PRN titers of >120 mIU/mL. Among 106 potentially exposed HCWs, the estimated effectiveness of 2 doses of measles vaccine was 52% (95% confidence interval [CI], -207%-93%). CONCLUSIONS: Measles occurred in 6 twice-vaccinated HCWs, despite 2 having adequate pre-exposure neutralizing antibodies. None of the twice-vaccinated cases had severe measles, and none had onward transmission, consistent with laboratory findings suggesting a secondary immune response. Improving 2-dose MMR coverage among HCWs would have likely reduced the size of this outbreak.