For children who attend pre-school between the ages 2 and 4, do they tend to have better immunities (and therefore get sick less often) than elementary-school children who did not attend pre-school, as was stated by this article on the Wall Street Journal:
A new study promises to ease some of those fears: While children placed in daycare early do tend to get sick more often, they also stay healthier than other kids later in elementary school, apparently because their daycare experience has built up their immunity against colds and other infections.
The study, released today in the Archives of Pediatrics & Adolescent Medicine, found a higher illness rate mainly in children who are placed before age 2-1/2 in child-care centers with relatively large groups of 8 to 12 children. Compared with children who were cared for in their homes, these kids had more respiratory and ear inflections during early preschool and the same risk of infection between ages 3-1/2 and 4-1/2, based on the eight-year study of 1,238 families with newborns in 1998. However, they had lower rates of infection between ages 5 and 8.
What studies show the relationship between pre-school attendance and school-age through long-term immunity?