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Microbiome: The first 1,000 days

May 15, 2019

About the Author

photo of Allan Walker, MD

Allan Walker, MD, Contributor

Allan Walker is a Professor of Pediatrics and the Conrad Taff Professor of Nutrition Emeritus at Harvard Medical School (HMS) and Professor of Nutrition at the Harvard School of Public Health. He is the Chairman of … See Full Bio
View all posts by Allan Walker, MD


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July 10, 2019

So you recommend use of probiotics in infants? My 5 month old has dairy/soy intolerance and showed minor reaction to egg yolk. Our pediatric GI specialist was against direct use of probiotics. I’ve been taking probiotics since pregnancy – he has been exclusively breastfed

June 23, 2019

What effect do vaccines have on the microbiome?

Allan Walker, MD
July 12, 2019

There are no studies that I know of that look at vaccine versus no vaccine during the first year of life. Since almost all babies are vaccinated by the same schedule, the studies that have been done looking at the sequential appearance of microbiota during the first and second year of life probably suggest that there is not a major effect effect of vaccines. However, that needs to be specifically looked at before we can answer that question.

May 26, 2019

Similar to the above question, what is the effect on a newborn who was given antibiotics immediately post birth to avoid any potential infection (since 24 hours had passed from breaking waters to birth)? Vaginal delivery.

June 27, 2019

What effect do vaccines have on the microbiome?

Allan Walker, MD
July 12, 2019

A potential newborn whose mother has been give antibiotics or a baby who has been given antibiotics because of the amniotic fluid being discharged when sac broke up to 24 hours before delivery will probably have some disruption in the colonizing of it’s intestine. As stated in this blog a major influence in colonization comes from vaginal colonic bacteria mother provides in a vaginal delivery. The use of antibiotics during pregnancy or after birth is going to disrupt the microbiota. The longer the antibiotic is used and the more broad-spectrum the antibiotic the more likely it is that there is going to be a major disruption. In each of these cases, I think it works to give that mother or child or both a probiotic for a period of about ten days after antibiotics have been used in order to try to balance the health promoting bacteria with potential pathogens. A subsequent blog will discuss the impact of antibiotics used during pregnancy and in the first year of life on the microbiome and in turn it’s influence on health and disease.

May 18, 2019

For women who have strep B and have to take antibiotics during labor – what affect does this have on the baby’s microbione?

Allan Walker, MD
May 29, 2019

This situation necessitates that antibiotics be given. To try to counteract the effect of antibiotics on the transmission of maternal bacteria from mothers vaginal and intestinal cavities to the young baby mothers can be given a probiotic during their breastfeeding or the baby can be treated with a probiotic. Antibiotics when indicated are necessary. It is just that they are excessively used during the course of pregnancy and the newborn infant’s lifestyle. To counteract the effects of antibiotics on intestinal microbiota probiotics can be used.

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