AUTHOR=Medeiros Márcia Melo , Ingham Anna Cäcilia , Nanque Line Møller , Correia Claudino , Stegger Marc , Andersen Paal Skyt , Fisker Ane Baerent , Benn Christine Stabell , Lanaspa Miguel , Silveira Henrique , Abrantes Patrícia 

TITLE=Oral polio revaccination is associated with changes in gut and upper respiratory microbiomes of infants

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1016220

DOI=10.3389/fmicb.2022.1016220

ISSN=1664-302X

ABSTRACT=<p>After the eradication of polio infection, the plan is to phase-out the live-attenuated oral polio vaccine (OPV). Considering the protective non-specific effects (NSE) of OPV on unrelated pathogens, the withdrawal may impact child health negatively. Within a cluster-randomized trial, we carried out 16S rRNA deep sequencing analysis of fecal and nasopharyngeal microbial content of Bissau–Guinean infants aged 4–8 months, before and after 2 months of OPV revaccination (revaccinated infants = 47) vs. no OPV revaccination (control infants = 47). The aim was to address changes in the gut and upper respiratory bacterial microbiotas due to revaccination. Alpha-diversity for both microbiotas increased similarly over time in OPV-revaccinated infants and controls, whereas greater changes over time in the bacterial composition of gut (<italic>p<sub><italic>adjusted</italic></sub></italic> &lt; 0.001) and upper respiratory microbiotas (<italic>p<sub><italic>adjusted</italic></sub></italic> = 0.018) were observed in the former. Taxonomic analysis of gut bacterial microbiota revealed a decrease over time in the median proportion of <italic>Bifidobacterium longum</italic> for all infants (25–14.3%, <italic>p</italic> = 0.0006 in OPV-revaccinated infants and 25.3–11.6%, <italic>p</italic> = 0.01 in controls), compatible with the reported weaning. Also, it showed a restricted increase in the median proportion of <italic>Prevotella</italic>_9 genus in controls (1.4–7.1%, <italic>p</italic> = 0.02), whereas in OPV revaccinated infants an increase over time in Prevotellaceae family (7.2–17.4%, <italic>p</italic> = 0.005) together with a reduction in median proportion of potentially pathogenic/opportunistic genera such as <italic>Escherichia</italic>/<italic>Shigella</italic> (5.8–3.4%, <italic>p</italic> = 0.01) were observed. Taxonomic analysis of upper respiratory bacterial microbiota revealed an increase over time in median proportions of potentially pathogenic/opportunistic genera in controls, such as <italic>Streptococcus</italic> (2.9–11.8%, <italic>p</italic> = 0.001 and <italic>Hemophilus</italic> (11.3–20.5%, <italic>p</italic> = 0.03), not observed in OPV revaccinated infants. In conclusion, OPV revaccination was associated with a healthier microbiome composition 2 months after revaccination, based on a more abundant and diversified bacterial community of Prevotellaceae and fewer pathogenic/opportunistic organisms. Further information on species-level differentiation and functional analysis of microbiome content are warranted to elucidate the impact of OPV-associated changes in bacterial microbiota on child health.</p>