A new study out of Drexel University’s Dornsife School of Public Health found that while you might think having more day care facilities to your block might make you and your neighbors sick more often, that doesn’t appear to be the case.
Dr. Neal D. Goldstein, assistant research professor in Epidemiology and Biostatistics, led a team that measured the density of day care facilities in Philadelphia compared to areas where cases of whooping cough (pertussis) occurred in the city.
“Hypothetically, more day care use could translate to more children, parents and caretakers getting sick because of everyone being in contact with each other. But we wanted to ask the question, ‘Do these people carry germs back into the local community, making other kids sick?’” Dr. Goldstein explained. “The answer to that appears to be, ‘No.’ The presence of day care facilities in an area does not necessarily mean there is community risk of pertussis among kids.”
The researchers looked at reported cases of pertussis in Philadelphia among children up to age six from 2001 through 2013 — which amounted to 410 — and mapped them against registered day care sites — roughly 2,000 in the city. To measure density, the team broke out the city’s neighborhoods and assessed how many day care sites there were per square mile. They then overlaid these data with the number of pertussis cases also occurring in each neighborhood.
Varying levels of pertussis were found in the city’s different neighborhoods. While the city-wide average was six cases per neighborhood during the study time period, the South Broad-Girard Estates neighborhood showed 24 cases, with two nearby neighborhoods also having more than 10 cases. Center City, Fairmount-Spring Garden and Sharswood-Stanton at the center of Philadelphia and Overbrook Park-Wynnefield Heights in the west each had just three cases.
Analysis did not show any correlation between higher density of day care facilities and elevated prevalence of pertussis. Dr. Goldstein said the lack of correlation between day care density and pertussis could come down to Pennsylvania’s strict vaccination requirements for children in day care.
Data analyzed for the study — which Dr. Goldstein and co-authors Dr. Loni Philip Tabb, and Dr. Seth Welles, of Drexel, and E. Claire Newbern, formerly with the Philadelphia Department of Public Health, published in Public Health — show that vaccination is the most important preventive measure to fend off whooping cough. In a large control group of Philadelphia children who were included in the study because they did not contract pertussis, 81 percent were current on their immunization against the illness. Among the group studied because they had contracted pertussis, just 64 percent were immunized.
“This vaccination requirement should provide a base level of protection among children — and adults — provided that people have received the vaccine,” he said. “Granted, these vaccination requirements can be exempted out of for medical and nonmedical reasons, but, hopefully, there are sufficient numbers of vaccinated children — and workers — to cancel out any effects of those who aren’t vaccinated.”
Additional reasons for the lack of correlation between day care density and pertussis could include that the study didn’t take into account unregistered day care facilities, and the fact that people might not use day care in their immediate neighborhood. For instance, parents might use a day care closer to their job. Future research might look into both of those potential confounders.
“With this type of pressing public health work, we don’t always have the luxury of waiting for a prospective study, which is why it’s important to take a look at what data we have available today and analyze and report on what we see,” Dr. Goldstein concluded.
Those interested in reading the full study, “Density of day cares in relation to reported pertussis incidence in Philadelphia,” can access it here.