Daycare May Facilitate Spread of Dangerous Bacteria, Researchers Found

Children who play together share more than toys; they also share germs. The potentially dangerous bacteria Streptococcus pneumoniae may spread more rapidly among children who attend day-care, according to a recent study conducted by Harvard Medical School (HMS) researchers.

A paper published in this month’s American Journal of Epidemiology listed community-level risk factors for the spread of S. pneumoniae, which included household size, socioeconomic status, and attendance at day-care facilities.

The researchers, including first author Susan S. Huang, an instructor at HMS in Infectious Diseases and an attending physician at Brigham and Women’s Hospital, designed a regression model showing that the likelihood of carrying pneumococcus may be predicted with better success at the community level than at the individual level.

Researchers wrote that these findings suggest that efforts to decrease infections may now target communities, not individuals.


S. pneumoniae causes a number of childhood infections, ranging from mild, such as ear infections and bronchitis, to more severe, such as pneumonia and meningitis, which are less frequent, according to Huang.

The bacteria often exist in the nose and throat without any adverse effects and researchers are still uncertain what causes the bacteria to grow out of control, said Huang.


Despite the higher incidence of carriage among those children who attended day-care facilities, Huang said she believes childcare facilities still confer a very great benefit to children.

“The solution is not to stop letting children play with one another,” said Huang. “The solution is to find better hygiene.”

One approach is to encourage use of a childhood vaccine released in 2000 that helps decrease illness due to pneumonococi, according to the study.

Other steps to take include encouraging good hand-washing habits and washing toys that multiple children play with, said Huang.

The study used data from 742 children in 16 Massachusetts communities. The children were tested for presence of the bacteria at both sick and well visits to pediatricians.

Going to day-care did not increase infection among children of socio-economically depressed neighborhoods but day-care attendance did increase infection among children in socio-economically advantaged areas.

The increase in carriage for economically advantaged children attending childcare facilities was two- to three-fold.

However, children in poorer areas were two to three times more likely to be infected to begin with.

The study suggested that one reason for this could be that “conditions of close contact among numerous young children in child care may enhance pneumococcal transmission similar to conditions of disadvantage, perhaps related to poverty, crowding, or limited opportunities for good hygiene.”

The study did not differentiate between the types or sizes of day-care facilities, said Huang. “A mathematical model is a very simplistic view of life,” cautioned Huang.