Having a sibling or other close relative with a history of staph infections greatly increases family members' risk of contracting an infection, according to a study in the Annals of Internal Medicine.
Researchers reviewed a Denmark national registry to determine if a history of Staphylococcus aureus infection in close relatives is associated with greater risk of infection. They found that the risk was indeed higher, especially if the family member in question was a sibling, as opposed to a parent.
According to the researchers, the increased risk is not because of direct transmission, because in 80 percent of the exposed individuals were infected with a different staph strain than that of their relatives.