In a follow-up to recent circulating vaccine-derived poliovirus type 3 (cVDPV3) in Jerusalem, the Israel Ministry of Health issued some information about poliovirus, the vaccines and the history of polio in the State of Israel (computer translated):
What is polio?
Polio (Poliomyelitis) is an infectious disease caused by the polio virus, which belongs to the group of intestinal viruses.
The virus is transmitted from person to person following contact with the feces (usually feces, but possibly also respiratory) and multiplies in the digestive tract of the person who infected that person can continue to infect others through the feces.
Most cases of infection (80-90%) are asymptomatic. In 10-20% of cases the disease is manifested by general symptoms such as fever, headache, abdominal pain, nausea and vomiting or sore throat. There can rarely be a sign of meningitis. The disease lasts about 2-5 days and passes.
The most alarming form, which occurs in less than 1% of cases, is the appearance of paralysis due to the penetration of the virus through the blood into the body and damage to the nervous system leading to mild paralysis of organs, hence the disease is called “pediatric paralysis”. The severity of the paralysis depends on the number of nerve cells affected. Paralysis occurs more frequently in the lower extremities and can be accompanied by severe muscle aches. There may also be paralysis of the respiratory muscles and need for respiration (which led in the 1950s to the term “iron lungs” for people who were affected in this way by the virus and required chronic respiration).
Why is it advisable to get a polio vaccine?
There is no cure for polio but it is easy and effective to prevent the disease by vaccination.
The polio virus vaccine is the most effective means of preventing infection with the virus and protecting against the disease. The vaccine has been around for decades, is effective and safe, and has led to the eradication of polio in places where there is strict adherence to immune coverage.
What polio vaccines are available in Israel?
In Israel, there are two types of polio vaccines that are part of the routine immunization program for children: the IPV – Inactivated Polio Vaccine and the bOPV – Bivalent Oral Polio Vaccine.
IPV is a killed vaccine, given by injection into a muscle. It is available in 4 doses in the first year of life: at 2 months, 4 months, 6 months and one year. Then a booster dose in second grade.
OPV is an attenuated live vaccine given by mouth drops, in two doses at 6 months and 18 months of age.
Are there any special guidelines for Jerusalem residents?
Following the discovery of the case in Jerusalem, it was decided at this stage to bring forward the vaccination age for infants in order to increase the protection of those children. The first dose (IPV) will be given at 6 weeks of age and the second (IPV) dose will be given at 12 weeks, as part of the “pentavalent vaccine”. The rest of the shots will be given at the usual time.
Is it necessary at this stage to vaccinate the entire population?
No. Most of the population in Israel is vaccinated. At this stage the Ministry of Health is focusing on completing vaccines for children who have not yet been vaccinated.
Are polio vaccines safe and effective?
Yes, the vaccines are safe and effective and it is important to get them according to the schedule of the Ministry of Health.
Some vaccinators may develop mild side effects such as fever and a local allergic reaction. These symptoms usually pass quickly.
A very rare side effect of paralysis after attenuated live vaccine is known but this phenomenon is completely avoided when the vaccine is given after a previous dose of killed vaccine, IPV, as done in Israel.
A child vaccinated with the attenuated animal vaccine continues to secrete the vaccine virus for several weeks in the feces. If the child or any of his family members is vaccinated, a weakened live vaccine should be avoided.
Polio monitoring in Israel
The Ministry of Health’s monitoring for poliovirus is two-fold:
Sewage monitoring – samples of sewage at 14 sampling sites in the country once a month.
Clinical monitoring – reporting cases of mild paralysis in children who are continuously reported to the Ministry of Health.
History of polio in the State of Israel
The vaccination program in the State of Israel began in 1957 with a killed vaccine and in 1961 a weakened live vaccine was added to the routine vaccination program.
Clinical cases have diminished over the years as the vaccination program has expanded. The last case of polio was in 1988.
Until 2005, a combination of vaccines (killed + attenuated animals) was given. In light of the fact that polio was not found in sewage monitoring from 1995 to 2005, and similar to a similar decision in the US in 2000, it was decided this year to discontinue the attenuated live vaccine and continue with only a killed vaccine.
In 2013, a natural polio virus was isolated in sewage in samples from the south of the country. No cases of polio were found at the time. Following this, Operation “Two Drops” was launched to increase coverage in the attenuated live vaccine, and it was decided to return the vaccine to the routine immunization program.
From 2014, a combination of the two vaccines (IPV + OPV) was again provided as part of the routine immunization program.
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