Caesarean section or natural birth? A study published in “Nature Communications” presents new evidence in favor of vaginal delivery. Children born by natural childbirth respond better to vaccination against bacteria such as tuberculosis or meningitis than those born by caesarean section.
The study finds that the way we are born is associated with the way the immune system will respond to two key childhood vaccines, tuberculosis and meningitis.
Conducted in Scotland and the Netherlands, the research shows that babies born naturally had higher levels of antibodies compared to those born by caesarean section after receiving vaccines that protect against the bacteria that cause lung infections and meningitis.
Researchers from the University of Edinburgh, Spaarne Hospital and University Medical Center Utrecht, and the Netherlands National Institute for Public Health and the Environment studied the relationship between gut microbes and antibody levels after vaccination in a cohort of 120 babies, who were vaccinated at 8 and 12 weeks against lung infections and meningitis.
The team analyzed the development of the gut microbiome, the community of microbes that lives in our bodies, in the first year of a child’s life and their immune response to vaccines by analyzing saliva samples at 12 and 18 months.
In the 101 babies tested for antibodies as a result of the vaccine that protects against lung infections, they found double the levels of antibodies in babies born naturally compared to those born by C-section.
Furthermore, they saw that breastfeeding was linked to 3.5-fold higher antibody levels compared to formula-fed infants who had had a natural birth.
Antibody levels as a result of the vaccine that protects against meningitis were tested in 66 babies. The experts found that antibody levels were 1.7 times higher for babies born naturally, regardless of breastfeeding, compared to those born by caesarean section.
The gut microbiome is seeded at birth, develops rapidly during the first months of life, and is primarily influenced by mode of delivery, lactation, and antibiotic use.
The team also found a clear relationship between the microbes in the gut of these babies and the levels of antibodies.
For example, among a large number of bacteria in the intestine, high levels of two in particular, Bifidobacterium y E. Coli, were associated with a high antibody response to the vaccine that protects against lung infections.
High levels of E. coli have also been linked to a high antibody response to the vaccine that protects against meningitis.
The microbiome of babies in the first years of life contributes to the immune system’s response to vaccines
The baby acquires the Bifidobacterium and E.coli bacteria through natural birth and human milk is needed to provide the sugars for these bacteria to thrive.
The team concludes that the microbiome of babies in the first years of life contributes to the immune system’s response to vaccines and sets the level of protection against certain infections in childhood.
Experts suggest that, in the future, vaccination schedules could be adjusted based on the mode of delivery or an analysis of the baby’s microbiome.
«We expected to find a link between the gut microbiome and infant vaccine responses, however we never expected to find the strongest effects in the first weeks of life», says Emma de Koff, first author and researcher at the University of Amsterdam Medical Center
Debby Bogaert, study leader and Chair of Pediatric Medicine at the University of Edinburgh, acknowledges: “It is particularly exciting that we identify beneficial microbes that may be the link between mode of administration and responses to vaccines. In the future, we may be able to supplement those bacteria to infants delivered by caesarean section soon after birth by, for example, ‘tfecal scrapings‘ from mother to baby or the use of specifically designed probiotics.
It is possible that these bacteria can be supplemented to those born by caesarean section through ‘fecal transplants’ or probiotics
For Patricia Perez Matutefrom the Department of Infectious Diseases of the CIBIR-San Pedro University Hospital, the implications, if corroborated in larger cohorts and with more complete immunological analyses, “would be that a treatment could be carried out with something as simple as probiotics (a Bifidobacterium-based or beneficial microorganisms), microbial metabolites (such as short-chain fatty acids produced by bacteria with anti-inflammatory action) or fecal transplants from the mother in those children born by caesarean section to enhance their immune response to future childhood vaccines (in this case of meningococcus and pneumococcus) and, with this, achieve a stronger immune system”.
However, he warns in statements to SMC, “from my point of view there are several limitations in this work that make it difficult to extrapolate its conclusions to clinical practice.”
To begin with, he notes, “eThe number of babies included is not very large». In addition, the analysis of the microbiota has only been carried out in 10 individuals born by vaginal delivery and another 10 by cesarean section. Although samples are collected at different time points (which is a strength of the study), “such a small size makes it difficult to draw conclusions that can be extrapolated to other populations.”
Likewise, he adds, there is some variability at the time of sample collection.