This weekend, the first case of polio paralysis in about 30 years was discovered in Israel, in an unvaccinated four-year-old girl. Its condition is relatively mild, but public health doctors estimate that the existence of a symptomatic polio case in Israel indicates the existence of dozens to hundreds of carriers of the virus without symptoms. Is that a cause for concern? In light of the high level of polio immunity in the population, the Ministry of Health estimates that a polio wave is not currently expected in the country.
Where did the virus come from?
About 90% of polio carriers do not feel symptoms. 1 in 200 people will develop permanent paralysis. In rare cases, the paralysis will reach the airways and then it can cause death. Some people with mild polio will suffer later in life from muscle weakness known as post-polio syndrome. There is no cure for the disease today, only supportive care.
Polio infection occurs through infected feces that have somehow reached the mouth, that is, through unwashed food or dirty hands. Where did polio come to Israel this time? Well, there is no pleasant way to say this: probably from the polio vaccine.
Polio vaccines are divided into two types: killed virus and attenuated virus. The killed virus is 90% -100% effective when given 3-4 doses, so the Ministry of Health’s immunization program today includes only it. Only children who are sensitive to one of its components receive the live-attenuated vaccine. These may not start with polio, but they can spread the virus. This has advantages: vaccinated people who are exposed to the virus in such a version will strengthen their immunity, as will most of the non-vaccinated who will encounter it.
In very rare cases, the live-attenuated virus can harm those who are not vaccinated, especially if they are immunosensitive. The current case occurs about a decade after the operation in which live-attenuated vaccines were given as part of preparations to prevent a polio outbreak in the country, after polio marks were found in the sewers and indicated that there were carriers in Israel. Then, despite the campaign, not a single case of symptomatic disease was found. Sewage tests plus epidemiological investigations currently underway indicate that the current outbreak is likely limited to a particular neighborhood in Jerusalem.
Who is at risk?
Ethically, this is a situation from the worlds of game theory. If 100% of Israelis were vaccinated, polio probably would not have spread and reached the girl who developed symptoms. On the other hand, if an attenuated live vaccine had not been used in Israel at all, it could not have been infected with it. On the other hand, those children who cannot be vaccinated with the killed vaccine were exposed to infection from the polio virus from nature, and the more unvaccinated in Israel, the more exposed they are.
In the past, polio was one of the most common diseases in the world, and one of the leading causes of disability and child mortality. As of early 2019, two polio strains have become extinct by vaccines and in total there are only a few dozen cases reported worldwide each year.
If so, who is in danger and should act now? Polio is especially dangerous for children up to the age of 5 and for those who suffer from immunosuppression. It is not entirely known whether the vaccine becomes obsolete and what the risk is for older patients who are immunocompromised in the event of an outbreak. Because of the way the disease is transmitted, hygiene is an important tool for preventing infection. 98% of the population is vaccinated, and those who are not vaccinated have been invited to receive the routine vaccines that include the killed virus. There is no need to boil the water, because the virus is usually found in the sewer and not in the drinking water. The guidelines are especially important in Jerusalem, where parents of infants have also been advised to test the possibility of advancing the vaccine compared to the routine program. In Jerusalem, immunization coverage is relatively low and only 83% of children are fully vaccinated.
Is the Ministry of Health prepared?
To deal now with the polio outbreak, the Ministry of Health is conducting comprehensive epidemiological investigations in Jerusalem and launching a special vaccination campaign for the same group that surrounds the infected girl. However, according to some public health physicians we spoke to, the capabilities of the Ministry of Health in this area are limited due to lack of resources.
A few weeks ago, the Ministry of Defense announced a reduction to a minimum of the sampling systems, investigations, hospital assistance and other support systems operated by the Ministry of Defense during the Corona period – mechanisms that the Ministry of Health and public health physicians claimed should be established regularly, not as a temporary emergency project.
According to Prof. Hagai Levin, head of the Association of Public Health Physicians, “Instead of establishing external temporary systems for the treatment of Corona, a permanent set of community health coefficients, health units in local authorities, school nurses and positive activities to raise vaccine coverage with the public would have prevented prevention and better coping. With the polio incident. “
Dr. Nadav Davidovich, director of the School of Public Health at Ben-Gurion University, adds: “Israel is good at operations, but routinely our vaccine levels are very low. Our health bureaus have strength, experience and professionalism, but it all relies on a staff that is close to retirement. New manpower is not attracted to the field because the salaries in it are low and the strikes of the medical manpower are skipping them. Soon we will not have good health bureaus.
“The Ministry of Health is also promoting a plan to gather global intelligence on epidemics, but now the Ministry of Finance has told them that they are ‘trying to make a round on the corona’ to get more budgets. And as if we had not learned anything. “