In the months since finding poliovirus in sewage, Israel has tried to analyze the severity of the situation. The process revealed that up to 2,000 people in the south of Israel may carry the poliovirus, prompting the government to buy 500,000 vaccines for an immunization campaign.
Israeli health minister Yael German told Channel 2 television that foreign laboratories' estimates of the number of asymptomatic carriers of poliovirus prompted the decision to begin vaccinating. Having reached the decision, the Israeli government bought 500,000 doses of a weakened live oral polio vaccine. GlaxoSmithKline ($GSK), Novartis ($NVS), Sanofi ($SNY) and the Serum Institute of India are all prequalified to supply oral polio vaccines, but it is unclear which company is supplying Israel.
Administration of the vaccine began on Monday, with Ynetnews reporting that 3,500 kids were immunized by midafternoon on the first day. The goal is to vaccinate 150,000 children up to the age of 9, AFP reports. Authorities hope the vaccination campaign will be enough to prevent a polio outbreak in Israel and help stop the virus from spreading beyond its borders. The health minister is already preparing contingency plans in case the campaign needs expanding, though.
"We are ready to order 500,000 more [doses] if necessary in the coming weeks," German said. Doubling the vaccine order would give the government enough doses to expand the immunization drive to other areas. Tests are being run to see if other parts of the country would benefit from the vaccine, Reuters reports. Israel has a high overall immunization rate, but some areas are better protected than others.
Any expansion is likely to face opposition from within Israel. The decision to use the active oral polio vaccine, instead of the inactivated form typically given in Israel, has been criticized, Haaretz reports. Israel chose the oral version because it is more effective than the inactivated vaccine, but it is also associated with more side effects. These side effects prompted Israel to switch to the inactivated form for its routine immunizations in 2005. In the years since Israel last used the oral form its safety profile has reportedly been improved by removing a polio strain.