First case since 1988 diagnosed earlier this week

Doctors warn of polio ‘outbreak’ threat as 2 new preliminary positive cases found

‘The tip of the iceberg’; Traces of disease also found in Jerusalem sewage, prompting fears that polio could be spreading in the city, particularly in ultra-Orthodox community

Nathan Jeffay is The Times of Israel's health and science correspondent

Illustrative image: An child receives an oral polio vaccine, 18 August 2013. (Yonatan Sindel/Flash90)
Illustrative image: An child receives an oral polio vaccine, 18 August 2013. (Yonatan Sindel/Flash90)

After Israel confirmed its first case of polio since 1988 this week, doctors said Friday that there are another two preliminary positive results from stool samples, raising fears of an outbreak.

An unvaccinated four-year-old girl was confirmed diagnosed on Sunday, and has now left Jerusalem’s Hadassah Medical Center for support in a specialist hospital, after the virus harmed her muscles.

The diagnosis marked the first clinical case of polio in Israel in 34 years.

The two preliminary results, which have not yet been confirmed, are believed to have come from a sample taken from a contact of the girl, while the second was found in a stool sample sent to labs for an unrelated matter, which was also tested for polio.

As far as it is known, the two new tests come from people who aren’t symptomatic.

“This is what I was afraid of — that the diagnosis of the hospitalized child would be followed by other positive tests,” polio expert Prof. Orna Tal, deputy director of the Shamir Medical Center, told The Times of Israel. “I’m concerned that there will be more cases and that there’s a threat of an outbreak.”

Hebrew University epidemiologist Prof. Hagai Levine said he is worried that what has been documented thus far is just “the tip of the iceberg.”

“We know from general experience that when you find one case of polio, you actually have dozens or hundreds,” he told The Times of Israel.

Workers preparing to distribute polio medication on August 4, 2013(Flash90)

Both Tal and Levine think there is a real prospect of the return of polio cases — in manageable numbers but enough to leave some children with long-term damage.

As well as detecting polio in the two new samples and diagnosing the patient — all of this in the Jerusalem area — the Health Ministry this week detected polio in Jerusalem sewage.

Levine said that this suggests polio is spreading in parts of Jerusalem, seemingly in ultra-Orthodox neighborhoods, commenting: “So far it’s located in Jerusalem and in ultra-Orthodox communities, but there is likely to also be transmission in other areas and in other communities.”

He said that analysis suggests that the virus found in samples came from contact with feces of children who received a vaccine that is made from the live virus. This can happen, for example, if an employee in a childcare facility changes the diaper of a newly vaccinated child and doesn’t wash hands before preparing food.

Tal said that the risk of infection via this route is normally very small, as most children are at least partially vaccinated from two months. “If you have 96% vaccination for people in Israel, as we do, this gives high protection,” she commented.

Levine was less optimistic, saying that while national vaccination rates are high, there are neighborhoods, especially in Jerusalem, where the take-up is much lower.

“If on a local level there is low coverage, that’s a problem, as when it comes to vaccination we’re as strong as our weakest link,” he said.

Israel started polio vaccinations in 1957, with killed vaccines and supplemented with a live — or attenuated — vaccines in 1961. In 2005, after a decade without polio showing up in sewage monitoring, the attenuated vaccines were stopped. But in 2013, polio was found again in sewage in southern Israel, and children have since been given the killed virus for some of their doses and the attenuated virus for others.

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