The law doesn't ban the ritual, but instead requires mohels to inform parents of the infection risks. Since 2004, the New York City Department of Health has received "multiple complaints from parents who were not aware that direct oral suction was going to be performed as part of their sons' circumcisions," according to a public notice.
In an affidavit supporting the suit, Rabbi Levi Heber of the International Bris Association said mohels are trained to ensure they perform the procedure in accordance with Jewish law and without exposing the child to any harm.
"A mohel will absolutely not perform a bris if he is experiencing any cold sores," Heber wrote, adding that mohelim may also rinse their mouths with antiseptic and minimize the duration of oral contact with the wound. "In my experience, these precautions are more than sufficient to assure the safety of metzitzah b'peh, which is performed tens of thousands of times each year without incident."
But Schaffner called such precautions "totally inadequate."
"People can carry the herpes virus without ever experiencing or recognizing lesions in their mouths," he said. "They could then transmit the virus to the infant, even though they have no symptoms themselves."