Measles, the need for a paradigm shift

Abstract

Measles vaccination schedules and targets of herd immunity have been designed according to the paradigm that the vaccine is as protective as natural infection, and the virus has remained of a single serotype over many decades. As a result, ongoing measles resurgence is mostly attributed to gaps in immunization. Using official data, we investigated the correlation between the rate of vaccine coverage reported and aggregated at the national level, and the incidence of cases. We discussed the limits of this indicator considered in isolation. We provide a literature overview of measles vaccine efficacy and failures. We questioned whether measles strains could escape the vaccine. Immunization tools and strategies for measles control deserve to be optimized in the current context.

Molecular Epidemiology of B3 and D8 Measles Viruses through Hemagglutinin Phylogenetic History

“…Although the vaccines currently in use are generated from strains isolated over 50 years ago, they are still highly effective at providing protection [8]. However, the persistent occurrence of measles outbreaks in highly vaccinated populations [9][10][11][12] suggests that the assumption of measles remaining serologically monotypic may have to be re-evaluated, as also underlined by Javelle and colleagues [13]. The vaccination coverage to be achieved to obtain herd immunity and prevent epidemics from indigenous or imported cases depends on the vaccine efficacy.…”

Measles, mumps, rubella prevention: how can we do better?

“…Measles outbreaks occur mostly in unvaccinated or undervaccinated individuals [40,50]. One of the explanations for the resurgence of measles outbreaks in several countries with available vaccination services is the increasing proportion of individuals who are delaying or refusing vaccination for themselves or their children.…”

“…The remaining pockets of unvaccinated or under-vaccinated individuals, who may be responsible for outbreaks and transmission, should be identified and targeted [40].…”

“…For measles, the global annual incidence decreased by 83% and the number of measles deaths by 80% between 2000 and 2017 [25]. However, since 2017, measles incidence has increased [25,40,41], and large outbreaks have been reported in several areas, including European countries, in a wide range of contexts and due to diverse causes [25,[29][30][31][32][33]42]. Concerning the incidence of mumps, decreases from 100 to 1,000 cases per 10,000 population in the absence of immunization to <1 case per 100,000 population within 10 years after the introduction of immunization programs were observed in several countries [4,26,27].…”

“…However, mumps outbreaks still occur, especially in older adolescents and young adults [26,27]. In contrast with measles outbreaks which mostly occur in unvaccinated individuals [40], mumps outbreaks were also reported in countries with high vaccination coverage rates [3,[34][35][36][37][38][39]43,44]. For rubella, the number of reported cases has declined by 97% after the introduction of the vaccination campaigns [28].…”