An ancient form of circumcision called metzitzah b'peh, which is sometimes performed by Orthodox Jews on newborn boys, appears to be behind the spread of herpes simplex virus type 1 (HSV-1) to two newborns in New York

Both boys were born to mothers who carried full-term and had normal deliveries. During the ritual, however, the person doing the circumcision uses direct oral suction in an attempt to cleanse the wound, sucking and spitting aside the blood, and the saliva contact can transmit the infection. More than half of American adults have HSV-1, according to the University of Pennsylvania School of Medicine, the most common symptom being oral lesions. Newborns, however, can run high fevers, have seizures, and even die if infected. Since 2000, 16 cases of herpes likely following this type of circumcision have been reported, three in 2014 alone, and there have been two deaths and two instances of brain damage. In a 2012 report, the American Academy of Pediatrics concluded that circumcision is safe and provides health benefits, but that direct oral suction should be avoided due to risk of infection.