Additional Evidence on Serological Correlates of Protection against Measles: An Observational Cohort Study among Once Vaccinated Children Exposed to Measles
Tom Woudenberg,
Rob van Binnendijk,
Irene Veldhuijzen,
Frits Woonink,
Helma Ruijs,
Fiona van der Klis,
Jeroen Kerkhof,
Hester de Melker,
Rik de Swart,
Susan Hahné
Affiliations
Tom Woudenberg
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Rob van Binnendijk
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Irene Veldhuijzen
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Frits Woonink
Public Health Service, Region Utrecht, De Dreef 5, 3706 BR Zeist, The Netherlands
Helma Ruijs
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Fiona van der Klis
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Jeroen Kerkhof
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Hester de Melker
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
Rik de Swart
Department of Viroscience, Erasmus MC, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
Susan Hahné
Centre for Infectious Disease Control, Netherlands Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoek 9, 3720 MA Bilthoven, The Netherlands
To assess correlates of protection against measles and against subclinical measles virus (MV) infection, we recruited once-vaccinated children from geographic regions associated with increased MV circulation and/or at schools with low vaccination coverage in the Netherlands. Paired blood samples were collected shortly after onset of the measles outbreak and after the outbreak. A questionnaire was used to document the likelihood of exposure to MV and occurrence of measles-like symptoms. All blood samples were tested for MV-specific antibodies with five different assays. Correlates of protection were assessed by considering the lowest neutralizing antibody levels in children without MV infection, and by ROC analyses. Among 91 participants, two seronegative children (2%) developed measles, and an additional 19 (23%) experienced subclinical MV infection. The correlate of protection against measles was lower than 0.345 IU/mL. We observed a decreasing attack rate of subclinical MV infection with increasing levels of specific antibodies until 2.1 IU/mL, above which no subclinical MV infections were detected. The ROC analyses found a correlate of protection of 1.71 IU/mL (95% CI 1.01−2.11) for subclinical MV infection. Our correlates of protection were consistent with previous estimates. This information supports the analyses of serosurveys to detect immunity gaps that require targeted intervention strategies.
