Could Israel be facing a polio outbreak and how can it be prevented?

What even is polio? How can you get infected with it, and what is the Health Ministry doing to prevent an outbreak?

ARAB RESIDENTS of Jerusalem take their children to get the polio vaccine at a Tipat Halav clinic in the Armon Hanatziv neighborhood in 1988. (photo credit: AYALON MAGGI/GPO)
ARAB RESIDENTS of Jerusalem take their children to get the polio vaccine at a Tipat Halav clinic in the Armon Hanatziv neighborhood in 1988.
(photo credit: AYALON MAGGI/GPO)

A four-year-old child in Jerusalem tested positive for polio on March 8, the first recorded case in Israel since 1989.

Since then, the Health Ministry has started extensive testing in order to determine whether the virus has spread to other children, and if so, what this could mean for the country.

What is polio?

Polio, or Poliomyelitis, is a highly infectious disease that is usually spread from person to person via contaminated food or water. Those infected with the disease can spread it for up to six weeks, even if no symptoms are present.

Between 80%-90% of polio cases are asymptomatic. Only 10%-20% of patients develop symptoms such as fever, headache, abdominal pain, nausea and vomiting or sore throat.

 Public Health Services Dr. Sharon Alroy-Preis, December 30, 2021. (credit: AVSHALOM SASSONI/MAARIV) Public Health Services Dr. Sharon Alroy-Preis, December 30, 2021. (credit: AVSHALOM SASSONI/MAARIV)

However, in less than 1% of cases, the virus can damage the nervous system, leading to paralysis of organs and limbs. Should it reach this stage, there is a 15%-30% mortality rate in both children and adults.

How many new cases have been detected in Israel so far?

Since the four-year-old Jerusalem boy tested positive for the disease, the Health Ministry has reported finding evidence of the virus in an additional two stool samples from Jerusalem and the surrounding areas

One of the positive samples was taken as part of the epidemiological investigation launched into any people who had been in contact with the infected child.

In addition to the positive sample, three negative samples were found in people close to the infected child, and an additional 19 are currently undergoing testing at the Central Virus Laboratory in Sheba Medical Center, Tel Hashomer.

The other positive case was found during random testing and was not known to be from a person who came close to the infected child. In response, the Health Ministry is expanding its investigation, testing additional samples in Jerusalem’s sewage system and the surrounding areas.

How can people prevent being infected with polio?

After the four-year-old tested positive for polio, it was discovered that his parents had chosen not to vaccinate him against the life-threatening disease. As there is no known cure for the disease, the best protection against it is the polio vaccine.

The polio vaccine is available in two different forms – the oral poliovirus vaccine (OPV), and the inactivated poliovirus vaccine (IPV) – both of which are routinely given in Israel.

OPV contains a weakened version of two different polio variants. Due to the fact this version of the vaccine contains a weakened form of the live virus, there are rare occurrences when a community has low vaccine coverage, and the virus may begin to circulate and mutate, infecting others and causing a new outbreak.

IPV, however, does not contain a live virus and therefore cannot mutate and infect others. However, it does not stop transmission of the disease and so OPV is the only version of the vaccine used when an outbreak needs to be contained. IPV, in contrast, is used exclusively for routine immunization.

How can an outbreak be prevented in Jerusalem?

Prevention of a polio outbreak in Jerusalem is two-fold, according to the Health Ministry.

The first step is for anyone who has yet to be vaccinated against polio to receive their IPV vaccine. However, because this does not prevent the transmission of the disease once the outbreak has already begun, those in the affected community will also be required to receive the live virus vaccine with the OPV.

In response to the polio case found earlier in the week, Public Health Services head Dr. Sharon Elroy-Preis recommended that the vaccination age of infants be brought forward, meaning that the first dose of the vaccine (IPV) be given at six weeks after birth and the second at 12 weeks.

The Health Ministry has also stressed the increased risk that healthcare and sewage workers face of coming into contact with the disease and recommended an additional dose of the IPV vaccine in addition to their routine vaccination schedule.

What steps is the Health Ministry taking to prevent an outbreak?

A campaign has been started by the Health Ministry in recent days in order to encourage vaccination in communities with low vaccination rates in Jerusalem and the surrounding areas. They are also increasing vaccination appointment availability.

They will also be placing an emphasis on the importance of the polio vaccine in the context of health education in schools, as well as a public information campaign that will work with healthcare companies and hospitals to raise awareness of the dangers of a polio outbreak.

Lastly, there will be increased monitoring of the Jerusalem sewage systems and continued examinations of stool samples in order to keep track of the spread of the disease, should it occur.

Speaking at a press conference earlier in the week, Health Ministry Deputy Director-General Dr. Sefi Mendelovich stressed that Israel is “far from an uncontrollable outbreak, and is working to prevent one,” adding that Israel’s monitoring system is extremely advanced and will be able to quickly pick up on new cases.

Elroy Preis noted, “The story of vaccine resistance has always existed in small percentages.

“We are making efforts within the Health Ministry and with other parties in order to raise awareness and provide information. There are populations that are hesitant to vaccinate and we aim to explain [the risks] to them.”