Seven months after the polio virus was discovered in Israeli sewage and four-and-a-half months after the introduction of a national vaccination scheme, the Health Ministry has concluded that the crisis is over. Haaretz has learned that recent samples from sewage treatment plants tested negative for the virus.

The finding, coupled with the fact that stool samples taken throughout this period from people in areas where the virus was present in sewage all tested negative, means the episode that began in May 2013 ended without a single new case of the disease.

“The polio crisis is indeed behind us, but we remain diligent,” Health Ministry Director General Dr. Ronni Gamzu told Haaretz. He noted, however, that because the virus has been detected in neighboring countries, the oral polio vaccine has been added to the regular vaccination schedule, “and it is important that the public continues to be vaccinated.”

Between 1990 and 2004 Israeli children received both the oral polio vaccine, consisting of a weakened, or attenuated, form of the live virus and the inactive polio vaccine, containing the inactive, or dead, form of the virus. In 2004 OPV was dropped from the immunization schedule, until the recent scare.

Ministry officials are cautiously starting to speak of the crisis in the past tense, moving on to analyze and to reach conclusions about the most significant public health event in Israel in recent years. Since the national vaccination drive began, on August 18, the oral vaccine was administered to 980,000 children under nine, or 79 percent of the 1.2 million children in Israel in this age group. Ministry officials say this high vaccination rate — it exceeded their expectations — coupled with the 98-percent vaccination rate for the inactive polio vaccine, means the entire Israeli population is adequately protected from the disease.

The rate of response to the emergency immunization campaign differed by geographical area, seemingly reflecting both heightened fear among parents living in the areas where the virus was detected in sewage and skepticism about the risk of infection.

According to the Health Ministry, vaccination rates were lowest in central Israel and highest in the periphery. The highest rate, 91 percent, was in the south, where the virus was first discovered, followed by 89 percent in the north, 79 percent in Haifa, 76 percent in Ashkelon and 72 percent in Jerusalem. In the central region as a whole only 68 percent of the target group was vaccinated, and in Tel Aviv the number dropped to 64 percent.

In the 1950s thousands of Israelis were crippled by polio. It did not emerge again until 1988, when a number of people contracted the disease. Still, the 2013 episode was different by almost every parameter: social, cultural and medical. The Health Ministry couldn’t even present one case to the public, which was skeptical about this seemingly virtual epidemic.

After the virus was detected in a number of sewage treatment plants in different areas of the country, Health Ministry and World Health Organization experts concluded that a national vaccination campaign was unavoidable.

“Such a move was bound to cause mass opposition, reintroducing the OPV after most of the world had stopped using it and without even one case of the disease,” Gamzu said, “Add to that the fact that 95 percent of the population had already received the IPV and some people claimed the OPV could cause the disease. I knew that I would encounter skeptics and firm opposition and that the medical community must give us its full backing.”

Second in Google searches after ‘Harlem Shake’

The ministry’s reasoning for the campaign involved a complex message, based on social solidarity. Parents were requested, in effect, to take their children, who had already received the IPV, to get the OPV in order to confer herd immunity on individuals who might not be immune to the disease — and all without a single actual case of polio.

Knowing the difficulties, the ministry went on the offensive. Gamzu himself visited leaders of several different religious and ethnic communities: ultra-Orthodox Jews, Ethiopian Jews, Druze and Muslims. During the High Holidays the ministry targeted synagogues. Some 30 doctors were called in to add their voice and answer questions on Facebook and other social media platforms.

Another difficulty was the “Question Authority” attitude of millennials, who doubted the necessity of the vaccination and sought information from alternative sources. “Polio vaccination” was the second most popular Google search in Israel in 2013, after “Harlem Shake.” Social media buzzed with the topic, and increasing numbers of groups urged parents not to bring in their children for the “two drops” vaccine.

“I wasn’t surprised by the opposition, since the message was complicated to begin with,” Gamzu says, “but I was surprised by the ability of relatively few people to cause such a wave of opposition. This is obviously due to social media, and couldn’t have occurred in 1988. In comparison, Today’s public doubts the authorities more. Still, these groups never presented any medical figure to argue with us, and I found myself debating the issue on the radio with a mother who didn’t want to vaccinate her child. Obviously, I respected her, but that was the nature of the opposition. My attitude was that I was the one who must tell the public what to do, and I said ‘Go get vaccinated.’ I’m the chief physician of the country, and that’s my job. I was backed by the medical community and the health minister.”

Officials came to realize that the strongest opposition was in the pluralistic, anti-establishment “State of Tel Aviv.” Gamzu says he sees even the low vaccination rate in the city — just 64 percent — as a victory that reflects “the trust of the citizens who were exposed to the most outspoken opposition ... That means one must get out and battle the negative messages and not give up.”

According to Health Ministry data, 183 cases of temporary adverse effects were reported, mostly fever, vomiting and diarrhea. There were also more severe cases of allergies, joint pain and seven cases of temporary limping.

The current crisis is over, but OPV will remain, joining the regular national vaccination scheme. It will be administered twice – at the age of six months and again at 18 months, on top of the IPV vaccination. Israel thus rejoins the list of states still using OPV, a decade after leaving it.