Acquired immunity to enteric viruses in an Indian birth cohort Público

Kates, Israel (Spring 2021)

Permanent URL: https://etd.library.emory.edu/concern/etds/n870zs090?locale=pt-BR
Published

Abstract

Diarrheal disease causes widespread morbidity and mortality among children under 5 globally; enteric viruses contribute to this burden. Acquired immunity due to initial infection has been shown to protect against re-infection by some enteric viruses, but the extent and duration of such immunity remains to be fully explored. We obtained a dataset of 373 children and 1,831 diarrheal episodes from an Indian birth cohort and examined natural immunity for astrovirus, sapovirus, norovirus GI and norovirus GII. We fit a Cox Proportional Hazards Model and obtained hazard ratios for virus-specific diarrheal episodes, comparing time to episode among children who had already experienced one virus-specific episode and those who had not yet experienced one. We also analyzed protection against overall diarrheal episodes (not virus-specific) as well as cross-protection between viruses, and lastly fit a frailty model to adjust our results for differential baseline risk. We found that a prior episode did not confer substantial protection against subsequent episodes associated with the same virus. Compared to those without a previous episode of astrovirus, children who had already experienced one had a slightly lower hazard of subsequent episodes of astrovirus (HR=0.83, 95% CI: 0.55, 1.25). Children who had already experienced an episode of norovirus GI had a 65% higher hazard of subsequent episodes involving norovirus GI (HR=1.65, 95% CI: 0.64, 4.25), although this effect was mitigated in the frailty analysis (HR=1.28, 95% CI: 0.53, 3.07). Sapovirus (HR=1.03, 95% CI: 0.77, 1.38) and norovirus GII (HR=1.08, 95% CI: 0.79, 1.48) did not show substantial protection. Children who experienced one diarrheal episode (regardless of pathogen presence) had a 30% higher hazard of subsequent episodes (HR=1.30, 95% CI: 1.10, 1.52); however, this was reduced in the frailty analysis (HR=0.86, 95% CI: 0.73, 1.02). Limited evidence of immunity may result from our episode-centered study design and small sample size. Results indicate host-specific factors that impact an individual’s risk may affect acquisition of natural immunity. Further research, including longitudinal seroprevalence and multi-site cohort studies, is needed to disentangle the extent and duration of acquired immunity to enteric viruses.

Table of Contents

Chapter 1: Literature Review

Chapter 2: Manuscript

About this Master's Thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Subfield / Discipline
Degree
Submission
Language
  • English
Research Field
Palavra-chave
Committee Chair / Thesis Advisor
Committee Members
Última modificação

Primary PDF

Supplemental Files