Impact of the Measles epidemic in Brazil: evaluation of the protective-immune response in naturally infected Measles patients and vaccinated individuals against circulating variants

• Grant number: 21/08864-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2023
• End date: July 31, 2027
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Edison Luiz Durigon
• Grantee: Ana Karolina Antunes Eisen
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Measles is a highly contagious exanthematic disease (R0 18) caused by the Measles morbillivirus (MeV) virus, requiring a vaccination coverage of 95%, despite being preventable by vaccination since 1963, it still remains an important cause of mortality, causing outbreaks especially when vaccination coverage in populations decreases. The vaccine is also composed of the attenuated virus of the original Edmonston strain belonging to genotype A, which currently only exists as a vaccine strain. In Brazil, as elsewhere in the world, the circulating strain is currently of the D8 genotype. Several reports of measles outbreaks in highly vaccinated populations as well as proven reports of secondary vaccine failure raise the question of whether the vaccine satisfactorily protects circulating wild genotypes. In Brazil, there was a large outbreak in 2018/2019 where it was noted that in some cases vaccinated people and/or children born to vaccinated mothers were infected. Thus, the objective of this project is to evaluate the cellular response and neutralizing antibody titers of naturally infected patients from the 2019 outbreak and vaccinated against wild (D8) and vaccine strains. For this, molecular diagnosis will be performed with differentiation between wild and vaccine strains, evaluation of cellular response by production of IFN-³ and flow cytometry, plaque reduction neutralization test (PRNT) and cytopathic effect viral neutralization test (CPE-VNT). (AU)