An ultra-Orthodox Jewish circumcision ritual is found to cause neonatal herpes infections in newborns in New York City, prompting health officials to encourage parents to consider the health risks of the practice.

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The report is sure to reignite a long-simmering debate over public health and religious liberties: the Centers for Disease Control and Prevention (CDC) reported on Thursday that 11 baby boys in New York City were infected with herpes between Nov. 2000 and Dec. 2011 following an ultra-Orthodox Jewish circumcision ritual called metzitzah b’peh — or oral suction — in which the mohel puts his mouth directly on the newborn’s circumcised penis and sucks away the blood.

Ten of the babies were hospitalized, at least two developed brain damage and two died, according to the New York City health department. In 2005, New York City Mayor Michael Bloomberg asked rabbis throughout the city to move away from performing metzitzah b’peh — and also issued an open letter [PDF] to the Jewish community warning of the health risks — but they refused claiming the practice was safe.

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According to the CDC report, the investigation into circumcision-related herpes infections in newborns began in 2004 when New York City’s Department of Health and Mental Hygiene (DOHMH) was notified of twin boys who had contracted herpes simplex virus type 1 (HSV-1, the type that causes cold sores and is usually transmitted orally) following circumcision with metzitzah b’peh; one twin died. Both twins were circumcised by the same mohel, whom the CDC report refers to as “mohel A.”

During the investigation, the DOHMH learned of another 2003 case of neonatal HSV-1 infection after circumcision, also involving mohel A. In all three cases, the babies’ mothers and the hospital staff who cared for the infants had no history of herpes infection. When mohel A was tested about three months after the 2004 circumcisions, he showed antibodies to HSV in his blood, but was not found to be actively shedding the virus.

In all three cases, the babies developed lesions or vesicles in their genital areas about 8 to 10 days after their ritual circumcision; the timing and location of the babies’ symptoms suggest that the infections were introduced during circumcision, the CDC reports. The health officials’ investigation further uncovered eight other similar cases through Dec. 2011 in New York City, bringing the total to 11.

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About 85% of all neonatal HSV infections (including HSV-2, which causes genital herpes) are transmitted during delivery from an infected mother, 5% of infections are congenital and 10% are acquired after birth, usually from adult caregivers. HSV-1 is extremely common in the adult population — infecting some 73% of New York City adults over 20 — but the CDC report finds that HSV-1 infection in baby boys is rare, with about three cases a year on average in New York City.

Based on the overall incidence of neonatal HSV infections, total birth statistics and estimates of boys being circumcised with direct oral-genital suction (about 3,564 a year in New York City), health officials estimate that the risk of HSV infection in baby boys after metzitzah b’peh is 3.4 times greater than in boys who aren’t exposed to oral suction. Overall, the risk of herpes infection following metzitzah b’peh was 24.4 per 100,000 baby boys between April 2006 and Dec. 2011, the CDC estimates.

The authors of the CDC report write:

Circumcision is a surgical procedure that can transmit infection if not performed under sterile conditions. Oral contact with an open wound in a neonate risks transmission of HSV and other pathogens. Professionals advising parents and parents choosing Jewish ritual circumcision should be aware of this risk, and direct orogenital suction should be avoided.

New York City Health Commissioner Dr. Thomas Farley also released a statement [PDF] urging that metzitzah b’peh not be performed. The health department also announced that several New York City hospitals, including those serving Hasidic Jewish communities, have agreed to distribute a brochure [PDF] describing the herpes risk to infants and advising parents considering out-of-hospital Jewish circumcision to ask the mohel before the bris whether he practices metzitzah b’peh. If so, parents can talk to their health-care providers and consider other options for circumcision.

“There is no safe way to perform oral suction on any open wound in a newborn,” Farley said. “Parents considering ritual Jewish circumcision need to know that circumcision should only be performed under sterile conditions, like any other procedures that create open cuts, whether by mohelim or medical professionals.”

(MORE: CDC: Why Are U.S. Circumcision Rates Declining?)

The following New York City hospitals will be distributing the brochure:

All HHC facilities

Maimonides

NYU-Langone

North Shore LIJ

Staten Island University

Lenox Hill

New York Methodist

New York Presbyterian

Forest Hills

During the course of the DOHMH investigation, health officials determined that four mohelim were confirmed to be involved in seven of the herpes cases. In two of those cases (involving the same mohel who circumcised two brothers three years apart), parents declined to reveal the identify of the practitioner, so it’s not clear whether he was the same mohel involved in any of the other cases. Therefore, the total number of mohelim involved in the 11 cases can’t be determined, but the investigators presume it is at least three and not more than eight.

(MORE: Study: Women with Circumcised Partners May Have Lower HPV Risk)

None of the mohelim are identified by name in the current CDC report. However, previous news accounts of neonatal herpes infections following ritual Jewish circumcision and oral suction in 2003 and 2004 identified Rabbi Yitzchock Fischer as the mohel. He was subsequently banned from performing the ritual in New York City.

“We’re not oblivious to what’s going on,” Rabbi David Zwiebel, executive vice president of Agudath Israel of America, told the New York Times in March, regarding the health risks surrounding metzitzah b’peh. He added: “The worst thing that could happen is if the authorities regulate this practice, then it could go underground. … I think the practice would continue, but there could be significant difficulty in gathering evidence.”

The CDC report is published in the agency’s Morbidity and Mortality Weekly Report.

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