Two infants in the last three months in New York City's ultra-Orthodox Jewish community have been infected with herpes following a ritual circumcision, according to the health department. The boys were not identified.
In the most controversial part of this version of the Jewish ritual, known as metzitzah b'peh, the practitioner, or mohel, places his mouth around the baby's penis to suck the blood to "cleanse" the wound.
One of the two infected babies developed a fever and lesion on its scrotum seven days after the circumcision, and tests for HSV-1 were positive, according to the health department.
Last year, the New York City Board of Health voted to require parents to sign a written consent that warns them of the risks of this practice. None of the parents of the two boys who were recently infected signed the form, according Jay Varma, deputy commissioner for disease control at the New York City Department of Health and Mental Hygiene.
Varma said it was "too early to tell" if the babies will suffer long-term health consequences from the infection.
Since 2000, there have been 13 cases of herpes associated with the ritual, including two deaths and two other babies with brain damage.
Neonatal herpes infections can cause death or disability among infants, according to the Centers for Disease Control and Prevention.
"First, these are serious infections in newborns and second, there is no safe way an individual can perform oral suction on an open wound," said Dr. William Schaffner, chair of preventive medicine at Vanderbilt University. "Third, these terrible infections are completely preventable. They should not occur in the 21st century with our scientific knowledge."
Some rabbis told ABCNews.com last year that they opposed on religious grounds the law requiring parents to sign a waiver, insisting it has been performed "tens of thousands of times a year" worldwide. They say safeguarding the life of a child is one of the religion's highest principles.
"This is the government forcing a rabbi practicing a religious ritual to tell his congregants it could hurt their child," Rabbi David Niederman, executive director of the Hasidic United Jewish Organization of Williamsburg, told ABCNews.com. "If, God forbid, there was a danger, we would be the first to stop the practice."