Israel is in the midst of a massive, emergency immunization drive of all children under the age of 9 against polio.
Health workers detected the virus in southern Israel in February. Since then, they've found it in 85 different sewage samples across the country, the Global Polio Eradication Initiative said Wednesday. Yet so far, no children have gotten sick or been paralyzed by the virus.
Israel has one of the highest rates of polio immunization coverage in the world, says Chris Maher of the World Health Organization. And that's one reason why the country has avoided polio cases, so far. But health officials are still very concerned about the situation.
The vaccination campaign aims to give polio boosters to a million children.
"There's no way that 100 percent of the population can be immune at any given time," Maher says. "So any time that virus is circulating [in the environment], if there's a person who's not immune, there's a risk that that person is going to get clinical polio. They're going to get infected, and they're going to get sick."
Israel's last polio case was reported in 1988, and the WHO declared the country polio-free in 1992. The fact that the virus is being found across a wide geographic area in Israel shows that it has re-established a foothold in the country, Maher says, and that it's reproducing in the community.
"The situation in Israel is a significant one because it represents an area of circulation in a world that really doesn't have very much polio anymore," he says.
Last year there were only 223 recorded polio cases on the planet. And they were in remote areas around Nigeria, Afghanistan and Pakistan. This year there have been 214 cases reported, so far, with 128 of them occurring in Somalia — a country that had been polio-free since 2008.
Genetic testing of the polio samples from Israel shows that the virus recently came to the Middle East from Pakistan. Exactly how it got there — by boat, plane, truck or bus — is unclear. But what is known is that the virus can travel inside someone's intestines without making that person sick and then escape into a new environment.
There's concern that the virus circulating in Israel may spill out of the country, says Emory University's Dr. Walt Orenstein, who has worked extensively on polio. "There's enough virus circulating [in Israel] that it could get out of that area in to other countries," Orenstein says.
To ensure the entire community is protected against polio, Israel has started using the oral vaccine, instead of the injectable one. The oral vaccine contains a weakened, live form of the poliovirus, which can spread through the environment and help immunize kids that don't get vaccinated.
Getting rid of polio flare-ups, like the one in Israel right now, is a crucial part of eradicating polio globally, Orenstein says. Although eradication efforts are focused on the remaining reservoirs in Nigeria, Afghanistan and Pakistan, he says, the rest of world can't let its guard down against the disease.
"We've got polio down. The issue now is to knock it out," he says. "That will give us global security that never again will this [disease] cripple our children or our adults."
STEVE INSKEEP, HOST:
Okay. To all the other security concerns in Israel you can now add this. The polio virus is spreading through Israel's sewage system. So far nobody has gotten sick, but Israel has launched a massive emergency immunization drive to revaccinate all children under the age of nine. NPR's Jason Beaubien reports.
JASON BEAUBIEN, BYLINE: The polio virus was first detected in southern Israel in February. Now it's been found in 85 different sewage samples across the country. Chris Maher, a senior advisor on polio eradication at the World Health Organization in Geneva, says there have no reports of Israelis getting sick or paralyzed, in part because Israel has one of the highest rates of polio immunization in the world. But he adds...
CHRIS MAHER: Any time that virus is circulating, if there's anyone who's not immune, there's a risk that that person is going to get clinical polio. They're going to get infected and they're going to get sick. And there's no way that 100 percent of the population can be immune at any given time so there is a risk in Israel itself that we will see clinical cases of polio.
BEAUBIEN: In response, the Israeli government last month launched a rapid vaccination campaign to re-immunize all kids under the age of nine against the disease. The drive aims to give polio boosters to a million children. Israel's last polio case was reported in 1988, and the WHO declared the country polio-free in 1992. Maher says the fact that the virus is being found across a wide geographic area shows that it has re-established a foothold in and it's reproducing in the community.
MAHER: The Israel situation is a significant one because it represents an area of circulation in a world that really doesn't have very much polio anymore.
Last year there were only 223 polio cases anywhere on the planet. And they were in remote areas around Nigeria, Afghanistan and Pakistan. Genetic testing of the samples from Israel show that the virus recently came to the Middle East from Pakistan. Exactly how it got there - boat, plane, truck, bus - is unclear. But it is known is that the virus can travel inside someone's intestines without making that person sick and then escape into a new environment.
Maher says there's concern that polio may now spill out of Israel.
As long as the virus is circulating, it's in people's guts, there is the possibility that the virus can, you know, move to another area where perhaps there's not as much protection as there is in Israel at the moment and where there's a greater opportunity for the virus not only to circulate but also to cause clinical disease.
BEAUBIEN: The current problem in Israel is driven in part by the type of vaccine they use. Israel uses a dead polio vaccine. It's given as a shot and doesn't contain any of the live polio virus. This dead vaccine is the same one that's used in the U.S. and most of the developed world. Most of the developing world uses a live oral polio vaccine. The oral vaccine is administered as a few drops into a child's mouth.
It contains a weakened, although still live, form of the polio virus. The injectable dead vaccine does a great job of protected the individual who is vaccinated, but the person can still carry the virus and pass it on. The oral live vaccine is better at wiping out polio in the entire community. To combat the current situation, Israel is switching over to the oral live vaccine to try to stop the transmission of the virus.
The Palestinian Authority actually uses both the live and dead vaccines in its routine immunization programs. Maher says this may be why the virus hasn't spread into the Palestinian territories. Jason Beaubien, NPR News. Transcript provided by NPR, Copyright NPR.