Does Having Pets Really Strengthen Your Immune System?

Many have fond memories of the family dog coming trotting up when they were a toddler and giving them a big lick on the face. Although parents (and children alike) may have run off shouting “Ugh, dog germs!” like Lucy in the Peanuts comic strip, those “dog germs” may have led to the development of a stronger immune system.

A recent Finnish study performed by researchers at Kuopio University Hospital found that babies who grow up in a home that has a pet are less likely to get coughs and colds in their first year of life than their counterparts who live in pet-free homes. Lead author of the study, Dr. Eija Bergroth, a pediatrician at the university, said, “We think the exposure to pets somehow matures the immune system so when the child meets the microbes, he might be better prepared for them.” Researchers believe that the dander that pets shed and the microbes that they bring in from outdoors prime babies’ newly-forming immune systems, teaching them to fend off allergies, bacteria and viruses.

Previous studies had found a link between the presence of pets in a baby’s home and a lower risk of allergies. And in a study performed on mice, exposure to household dust from a home in which a dog lived prevented a common respiratory virus that has been linked to the development of childhood asthma.

Researchers from the Finnish study, published in the journal Pediatrics, followed the health of 397 Finnish children during their first year of life. Parents recorded the state of their child’s health on a weekly basis, including any runny noses, coughing and ear infections. They also noted if the child took any antibiotics. The results of the study found that children with pets in the home had a 44% lower risk of contracting an ear infection and were 29% less likely to be prescribed antibiotics, when compared with babies from pet-free homes.

The type of pet in the home did make a difference in how likely babies were to become ill during their first year. Dogs in the home were associated with a 31% lower risk of illness in the first year, whereas the presence of cats in the home was associated with only a 6% improvement in risk. The greatest benefit was from outdoor pets (those that were not restricted only to the indoors), as they brought in a wider array of microbes on their fur.

According to researchers, early exposure to pets seems to be the key in developing greater resistance to microbes, as it is the time that a child’s immune system is learning to differentiate friendly from unfriendly microbes, and by getting a wide array of these in small amounts, babies’ immune systems become well-trained early on.