LABORATORY CHARACTERIZATION OF MEASLES VIRUS INFECTION IN PREVIOUSLY VACCINATED AND UNVACCINATED INDIVIDUALS.

Tuesday, 2nd of April 2013

[source]Journal of Infectious Diseases[|source]

This full text article describes clinical and serological bio-markers that one can use to differentiate measles in unvaccinated compared to secondary vaccine failures (SVF).  Clinically, there were fewer complications in those with presumed SVF than in those with acute primary infection. In the laboratory, Plaque Reduction Neutralization (PRN) titers were observed to be exceptionally high; they were 6–60 times the mean PRN titer seen after routine measles vaccination (1 or 2 dose) and were markedly higher than the titers observed after acute measles infection in unvaccinated individuals. Details are available at: http://jid.oxfordjournals.org/content/204/suppl_1/S549.long

Abstract

Waning immunity or secondary vaccine failure (SVF) has been anticipated by some as a challenge to global measles elimination efforts. Although such cases are infrequent, measles virus (MeV) infection can occur in vaccinated individuals following intense and/or prolonged exposure to an infected individual and may present as a modified illness that is unrecognizable as measles outside of the context of a measles outbreak. The immunoglobulin M response in previously vaccinated individuals may be nominal or fleeting, and viral replication may be limited. As global elimination proceeds, additional methods for confirming modified measles cases may be needed to understand whether SVF cases contribute to continued measles virus (MeV) transmission. In this report, we describe clinical symptoms and laboratory results for unvaccinated individuals with acute measles and individuals with SVF identified during MeV outbreaks. SVF cases were characterized by the serological parameters of high-avidity antibodies and distinctively high levels of neutralizing antibody. These parameters may represent useful biomarkers for classification of SVF cases that previously could not be confirmed as such using routine laboratory diagnostic techniques.