I can’t remember where I heard it. Maybe I made it up myself. But, one definition of a family is a group of folks with whom you share your genes and germs. In that same vein, one could define daycare as a group of germ-sharing children. Of course that’s news to almost no one. Parents who decide, or are forced, to send their children to daycare expect that those children will get more colds, “stomach flu,” and ear infections than the children who spend their days in isolation at home. Everyone from the pediatrician to the little old lady next door has warned parents of the inevitable reality of daycare. Of course there are upsides that parents can cling to, including increased socialization and the hope that getting sick young will build a more robust immunity in the long run.
However, there has been little research exploring the nuances of the germ sharing that we all know is happening in these and other social settings.
A team of evolutionary biologists at Harvard is working to better define the “social microbiome” and its “role in individuals’ susceptibility to, and resilience against, both communicable and noncommunicable diseases.” These researchers point out that while we harbor our own unique collection of microbes, we share those with the microbiomes of the people with whom we interact socially. They report that studies by other investigators have shown that residents of a household share a significant proportion of their gastrointestinal flora. There are other studies that have shown that villages can be identified by their own social biome. There are few social settings more intimately involved in microbe sharing than daycares. I have a friends who calls them “petri dishes.”
Dr. William G. Wilkoff
The biologists point out that antibiotic-resistant microbes can become part of an individual’s microbiome and can be shared with other individuals in their social group, who can then go on and share them in a different social environment. Imagine there is one popular physician in a community whose sense of antibiotic stewardship is, shall we say, somewhat lacking. By inappropriately prescribing antibiotics to a child or two in a daycare, he may be altering the social biome in that daycare, which could then jeopardize the health of all the children and eventually their own home-based social biomes, that may include an immune deficient individual.
The researchers also remind us that different cultures and countries may have different antibiotic usage patterns. Does this mean I am taking a risk by traveling in these “culture-dependent transmission landscapes”? Am I more likely to encounter an antibiotic-resistant microbe when I am visiting a country whose healthcare providers are less prudent prescribers?
However, as these evolutionary biologists point out, not all shared microbes are bad. There is some evidence in animals that individuals can share microbes that have been found to “increase resilience against colitis or improve their responsiveness to cancer therapy.” If a microbe can contribute to a disease that was once considered to be “noncommunicable,” we may need to redefine “communicable” in the light this more nuanced view of the social biome.
It became standard practice during the COVID pandemic to test dormitory and community sewage water to determine the level of infection. Can sewage water be used as a proxy for a social biome? If a parent is lucky enough to have a choice of daycares, would knowing each facility’s biome, as reflected in an analysis of its sewage effluent, help him or her decide? Should a daycare ask for a stool sample from each child before accepting him or her? Seems like this would raise some privacy issues, not to mention the logistical messiness of the process. As we learn more about social biomes, can we imagine a time when a daycare or country or region might proudly advertise itself as having the healthiest spectrum of microbes in its sewage system?
Communal living certainly has its benefits, not just for children but also adults as we realize how loneliness is eating its way into our society. However,
Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at pdnews@mdedge.com.