Performance of rotavirus vaccines in developed and developing countries

Abstract

The World Health Organization estimates that rotavirus diarrhea results in approximately half a million deaths and approximately 2.4 million hospitalizations in developing countries each year. Two live oral rotavirus vaccines, RotaTeq® (RV 5; Merck) and Rotarix® (RV 1; GlaxoSmithKline) with good efficacy against severe rotavirus disease and a reassuring safety profile could substantially impact the burden of rotavirus disease. In April 2009, WHO provided a recommendation for global introduction of these vaccines in national immunization programs of developing countries worldwide. In this article, we review published data on previous candidate rotavirus vaccines and vaccines in current use, with emphasis on their performance in developed versus developing countries. In developed countries, both first and second generation rotavirus vaccines have demonstrated high efficacy against severe rotavirus disease (pooled efficacy = 73% and 85%, respectively). In developing countries, small early trials for the first generation vaccines failed to provide protection against rotavirus disease (pooled efficacy = 20%), however, trials of the second generation vaccines yielded substantial improvements in efficacy in developing countries (pooled efficacy of 51%), leading to a global recommendation for rotavirus vaccine introduction by WHO. Future efforts for these vaccines should focus on optimizing the efficacy and delivery of these vaccines in challenging target populations of Asia and Africa with the greatest burden of severe rotavirus disease.

Le microbiote intestinal, un acteur de la réponse immunitaire adaptative antivirale ?

“…Un argument en faveur de cette hypothèse est l'observation selon laquelle de nombreux vaccins sont moins efficaces dans les pays en voie de développement que dans les pays industrialisés, probablement en raison de multiples facteurs modifiant la composition du microbiote intestinal [9]. Par exemple, l'efficacité du vaccin anti-rotavirus 3 de première génération est de 73 % dans les pays industrialisés, contre seulement 20 % dans les pays en voie de développement [10]. Cependant, le mécanisme mis en évidence pour le virus de la grippe ne peut pas être généralisé, et l'efficacité d'autres vaccins, tels que celui contre la fièvre jaune, l'hépatite B, ou encore le vaccin antidiphtérique, tétanique et poliomyé-litique, ne semble pas être affectée [8].…”

Rotavirus Infection: A Perspective on Epidemiology, Genomic Diversity and Vaccine Strategies

“…In general, less heterogeneity in study design was observed across these trials because of lessons learned from trials of first generation vaccines with regard to number of doses administered, vaccine titer, age at immunization, outcome measure, and time of follow-up. Similar to the first generation vaccines, in developed countries, the second-generation vaccines demonstrated high efficacy against severe rotavirus disease [47]. In addition, substantial improvements were noted compared with the first generation vaccines with regard to vaccine efficacy in developing countries where a pooled efficacy of 51% was observed [47,49].…”

“…A substantial reduction (59%) in admissions from all-cause gastroenteritis was also noted in the trial. Protection was good against all G1-4 and G9 serotypes (range 88-100%) [47]. Clinical trials in developing countries of Asia and Africa have recently been completed.…”

“…Similar to the first generation vaccines, in developed countries, the second-generation vaccines demonstrated high efficacy against severe rotavirus disease [47]. In addition, substantial improvements were noted compared with the first generation vaccines with regard to vaccine efficacy in developing countries where a pooled efficacy of 51% was observed [47,49]. While efficacy of the second generation vaccines was still lower in developing countries than efficacy in industrialized settings, the higher burden of severe disease in developing countries translated into a greater absolute reduction in severe rotavirus disease in the poorest settings [52].…”

“…In the early trials, a lower titer was used compared with subsequent trials of RRV-TV. The trials using lower RRV-TV titers yielded good protection (efficacy = 78%) in the US, but efficacy was lower in Brazil (46%) and Peru (30%), a middle and low-middle income country, respectively [47]. In subsequent studies of RRV-TV, a higher concentration (4 9 105) was administered in multiple doses to improve vaccine performance.…”