Abstract Title
Maternal humoral immunity and protection against norovirus GII gastroenteritis in a birth cohort
Presenter
Sylvia Becker-Dreps, University of North Carolina at Chapel Hill
Co-Author(s)
Sylvia Becker-Dreps (a,b), Paul Brewer-Jensen (b), Yaoska Reyes (b), Kimberly Enders (c), Nadja A. Vielot (a), Fredman González (d), Lester Gutiérrez (e), Jan Vinjé (f), Ralph Baric (b), Lisa Lindesmith (b), and Filemón Bucardo (a,g)
a Department of Family Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; b Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; c Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; d Independent Researcher; e Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; f Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, g Department of Microbiology and Immunology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
Abstract Category
Vaccines and immunity
Abstract
Introduction: Few studies have investigated protection conferred by transplacental or human milk antibodies against norovirus acute gastroenteritis (AGE).
Methods: In a Nicaraguan population-based birth cohort, children were followed weekly for AGE with RT-qPCR of stool for norovirus GII detection. Mothers provided serum after birth and monthly human milk samples. Maternal serum and milk were tested for binding and norovirus-ligand blocking antibodies against GII.2, GII.4 Sydney, and GII.12. To understand protection conferred by transplacentally-acquired blocking antibodies, we performed a case-cohort study of 38 GII AGE cases within the first 9 months of life and 80 disease-free controls. To understand protection conferred by blocking antibodies in milk, we performed a case-control study of 38 breastfed children experiencing GII AGE between 5-14 months of age and 76 age-matched controls.
Results: In the case-cohort, children whose mothers had higher serum blockade antibodies had a lower risk of becoming a case, but the associations did not attain statistical significance. For example, a one-fold increase in serum blockade titer to GII.12 was associated with a 14% lower risk of being a case (95% CI 0.74-1.01). In the case-control, the proportion of maternal milk samples with norovirus GII.4-specific IgA antibodies was higher in control vs. case children (86% vs. 76%), however there were no differences in proportions of norovirus-ligand blocking antibody titers/total milk IgA in cases vs. controls.
Conclusion: While our findings suggest a protective role for maternally-acquired antibodies against norovirus, we suspect that genotype-specific protection limited our ability to see strong associations within our available sample size.
Methods: In a Nicaraguan population-based birth cohort, children were followed weekly for AGE with RT-qPCR of stool for norovirus GII detection. Mothers provided serum after birth and monthly human milk samples. Maternal serum and milk were tested for binding and norovirus-ligand blocking antibodies against GII.2, GII.4 Sydney, and GII.12. To understand protection conferred by transplacentally-acquired blocking antibodies, we performed a case-cohort study of 38 GII AGE cases within the first 9 months of life and 80 disease-free controls. To understand protection conferred by blocking antibodies in milk, we performed a case-control study of 38 breastfed children experiencing GII AGE between 5-14 months of age and 76 age-matched controls.
Results: In the case-cohort, children whose mothers had higher serum blockade antibodies had a lower risk of becoming a case, but the associations did not attain statistical significance. For example, a one-fold increase in serum blockade titer to GII.12 was associated with a 14% lower risk of being a case (95% CI 0.74-1.01). In the case-control, the proportion of maternal milk samples with norovirus GII.4-specific IgA antibodies was higher in control vs. case children (86% vs. 76%), however there were no differences in proportions of norovirus-ligand blocking antibody titers/total milk IgA in cases vs. controls.
Conclusion: While our findings suggest a protective role for maternally-acquired antibodies against norovirus, we suspect that genotype-specific protection limited our ability to see strong associations within our available sample size.