1835 Live Attenuated Vaccines Induce Gut Cathelicidin Antimicrobial Peptide Response in Neonates - A Natural Experiment

Abstract

Background and Aims: Oral polio (OPV) and BCG vaccines are recommended to be given at birth for protection against tuberculosis and polio, while observational studies in developing countries demonstrate reduction of mortality from infections other than target disease. The mechanism of such non-specific beneficial effects is unknown. We investigated gut antimicrobial peptides response during neonatal period who had received these vaccines simultaneously within 48-hour of birth. Methods: In a cross-sectional study design, stool samples were collected from infants at 1 month of age who had (n=36) or had not (n=42) received both vaccines within 48 h of birth. Antimicrobial peptides- human cathelicidin (LL37) were measured in the extracted stool samples by ELISA. Demographic and anthropometric data were collected from the clinic and structured questionnaires. Results: Infants of the vaccinated group had 39.8% higher excretion of LL37 in stool at 1 month of age (P=0.02). Such induction is observed only to the infants who born normally (P=0.01). Sex difference had no effect. Multivariate analysis showed higher LL37 response (P=0.08) among vaccinated infants after adjusting for sex, place of birth, mother age, postnatal age and mode of delivery. Including birth weight along with other variables indicates birth weight is significant predictor of LL37 (P=0.05) irrespective of vaccination status. Conclusions: Induction of mucosal antimicrobial peptide LL-37 following on-birth live attenuated vaccination may provide protection against other infections and possible explain the observed non-specific survival benefit in developing countries where low birth weight remains significant public health problem.