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Does Daycare Improve Immunity? A Closer Look at the Evidence

Daycare, or out-of-home child care, has long been a subject of debate, especially among new parents. While concerns typically revolve around issues such as child development, costs, and separation anxiety, an interesting line of inquiry pertains to the effect of daycare on a child’s immune system. Does sending your child to daycare bolster their immunity or does it expose them to a higher risk of infectious diseases?

The Hygiene Hypothesis

The basis for the belief that daycare might improve immunity is rooted in the ‘hygiene hypothesis’. This hypothesis suggests that exposure to various pathogens during early childhood can stimulate the immune system and reduce the risk of developing allergies and asthma (Strachan, 1989). The idea is that regular exposure to diverse germs and viruses can help “train” the immune system, making it more robust and less likely to overreact to harmless substances.

Reference: Strachan, D. P. (1989). Hay fever, hygiene, and household size. BMJ, 299(6710), 1259-1260.

Evidence in Favor of Improved Immunity

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Several studies have suggested a link between daycare attendance and improved immune function:

  1. Reduced Allergies and Asthma: A study published in the journal “Pediatrics” found that children who attended daycare or had older siblings (thus exposed to more pathogens) during the first six months of life had reduced risks of allergies and asthma later in life (Ball et al., 2000).
  2. Resilience to Colds: Another study showed that while children in daycare might get sick more often than those cared for at home during their first year of life, they tend to get fewer colds and respiratory infections when they start school, suggesting a more developed immune response (Lau et al., 2005).


  • Ball, T. M., Castro-Rodriguez, J. A., Griffith, K. A., Holberg, C. J., Martinez, F. D., & Wright, A. L. (2000). Siblings, day-care attendance, and the risk of asthma and wheezing during childhood. Pediatrics, 105(4), 732-738.
  • Lau, S., Illi, S., Sommerfeld, C., Niggemann, B., Bergmann, R., Von Mutius, E., & Wahn, U. (2005). Early exposure to house-dust mite and cat allergens and development of childhood asthma: a cohort study. The Lancet, 356(9239), 1392-1397.

Counterarguments: Immediate Illness Concerns

While there may be long-term benefits to immunity, there are also short-term concerns. Children in daycare settings are indeed exposed to a greater number of infectious agents than those not attending. This means they might suffer from more frequent illnesses, such as colds, ear infections, and gastrointestinal bugs, during their early years in daycare (Haskins & Kotch, 1986).

For parents, this could mean more frequent doctor visits, more days off from work to care for a sick child, and the risk of transmitting the illness to other family members.


  • Haskins, R., & Kotch, J. (1986). Day care and illness: Evidence, costs, and public policy. Pediatrics, 77(6), 951-982.


Daycare might indeed play a role in strengthening a child’s immunity in the long run. Early exposure to pathogens could potentially decrease the risk of allergies, asthma, and even some infections later in life. However, it comes at the short-term cost of more frequent illnesses during the early years.

For parents weighing the pros and cons, it’s essential to consider both the immediate and long-term effects, and to be prepared for the higher likelihood of illnesses during the initial years of daycare. But it’s also comforting to know that these early challenges might be paving the way for a stronger immune system in the future. As always, decisions regarding childcare should be made in consultation with healthcare professionals and based on individual family needs and circumstances.