Polio vaccination 2015: the need and risks

On October 20, 2015, the first round of national immunization against poliomyelitis began in Ukraine.The main reason for the decision of the Ministry of Health of Ukraine about the advisability of such measures was the incident in the Transcarpathian region: two unvaccinated children from poliomyelitis were diagnosed with acute flaccid paralysis, which caused poliovirus of the first type of vaccine origin( WHO data).The circulation of this virus among the population, according to experts, is directly related to the critically low level of vaccine coverage from poliomyelitis of Ukrainian children.

Almost simultaneously with information about the outbreak of poliomyelitis in Ukraine, articles on the quality of the vaccine, which Ukrainian doctors plan to use for immunization, appeared on various Internet resources.The vaccine was provided to Ukraine by UNICEF in the framework of charitable assistance, however, during the process of customs clearance and transportation to the warehouses of "Ukrvaccine", the immunobiological drug was stored in inadequate conditions( it was thawed and re-frozen).

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In addition, it is worth mentioning the fact that the main contingent of patients vaccinated in Ukraine as part of the round of immunization are small children( from 2 months old), and they are vaccinated regardless of whether they werePreviously vaccinated by the vaccination calendar or not.In connection with all this, many parents have doubts as to whether their child needs additional immunization, as well as a lot of questions regarding the quality of the vaccine, the risk of developing post-vaccination poliomyelitis in vaccinated children and in contact.

Table of contents: Scheme of the round vaccination against poliomyelitis Why tour immunization in Ukraine?Was there a flash?TURN IMMUNIZATION IN TADJADIST AND RUSSIA What scares parents into the turf immunization?"Distressed" vaccine

Scheme of round vaccination against poliomyelitis

Vaccination of the vaccine is a mass immunization of certain categories of the population, which is conducted in order to stop the circulation and spread of the causative agent of a certain infectious disease.Such vaccination is carried out irrespective of the vaccinal status of the patient( vaccinations received).With the help of immunization, it is possible to protect a large number of unprotected populations from infections.

The number of rounds and contingent to be vaccinated is chosen according to the specific situation( from which infection, how immunity is formed, which age groups are most susceptible, etc.).For example, in Ukraine has planned three rounds for children from 2 months to 10 years( during the first two rounds they will vaccinate children under 6 years old, and during the third - all children under 10 years old) .This is what WHO recommends.

Why do you need immunization in Ukraine?

World experience of polio vaccine prevention shows that in order to stop and prevent the circulation of the pathogen of infection, it is necessary to cover with vaccinations 90-95% of the susceptible population. In Ukraine, since 2008, serious problems with vaccination have begun.For example, in 2008, 90% of children received polio vaccine, 90% in 2009, 80% in 2009, 57% in 2010, 54% in 2011, 73% in 2012, and 201372%, in 2014 - 44%, and finally, for 9 months 2015 - only 17% of children. Therefore, domestic physicians and WHO specialists can with great confidence believe that a large number of children have formed in Ukraine, who do not have sufficient immunity to this infection and are most at risk of getting polio.

Such a development of events is unacceptable for a country that since 2002 has entered a polio-free zone.All conditions for the active circulation of mutated polioviruses of vaccine origin, which can cause a paralytic form of poliomyelitis, and a great threat of renewal of the circulation of "wild" and most dangerous strains of the poliomyelitis agent in the event of their importation.

In connection with this situation, in 2014, WHO and UNICEF recommended that Ukraine take all measures to change the situation( in particular, several rounds of immunization for children born after 2008), but this did not happen.

The definitive push to begin a round of immunization in 2015 was the outbreak of poliomyelitis in the Transcarpathian region.

Was there a flash?

Acute flaccid paralysis, which was diagnosed in children from Transcarpathia, is not uncommon, each year in Ukraine they find about a hundred( in particular, for 10 months in 2015 - 115).Such patients are necessarily examined for the presence of poliovirus in the feces.And the feces are examined by special accredited WHO laboratories.Just such a certified laboratory and found in two sick children poliovirus vaccine origin( in both cases, the viruses had similar multiple mutations), which was the reason to declare an outbreak of poliomyelitis in Ukraine.

Circulating polioviruses of vaccine origin( cVDPV) are polioviruses that mutate from viruses that are contained in the OPV vaccine.When most people have immunity, a mutation is not possible, as vaccine viruses simply do not take root in the intestines of people who have been in contact with the vaccinated, and do not spread among the population.If people are not properly immunized, vaccine polioviruses are actively transmitted from one person to another.Several such passages lead to the appearance of mutations and the appearance of virulent properties in the virus, that is, the ability to cause disease.

Viruses isolated from children in Ukraine, according to WHO experts, have multiple mutations, which confirms their fairly long circulation among the population.That is, today many Ukrainian children can be carriers of such viruses.

For the complete eradication of poliomyelitis on the entire globe, it is necessary to eliminate not only the circulation of wild strains, but also cCPVV. To this end, WHO has developed a special strategy for the phasing out of OPV vaccine( a potential source of cVDPV) for vaccination against poliomyelitis.So, from April 2016 it is planned to apply a new version of OPV( it will contain only two types of the virus, since the circulation of the third one has not been observed for more than 10 years).However, in order to completely abandon OPV, it is necessary that people have sufficient level of both general and local immunity, and only live vaccine can create it.

Therefore, what happened in Ukraine( a country that is free of poliomyelitis for more than 10 years) to some extent threatens the WHO strategy for the complete eradication of poliomyelitis until 2018.

Thus, immunization in Ukraine is a necessary measure that fully meets the international standards adopted at the last World Health Assembly in 2015. In accordance with WHO recommendations, in such situations, a minimum of three large-scale supplementary immunization activities for OPV are required, with coverage of the target group - children under five years of age( in the case of Ukraine, the age range has slightly expanded, since many children have not been vaccinated after 2008).The use of OPV in such activities is explained by the need to create not only general but also local immunity in order to stop the circulation of the pathogen that may be present in the intestines of children.

Staging immunization in Tajikistan and Russia

Staging immunization is a common practice in countries with low vaccination coverage and polio outbreaks.Previously, it was held in Tajikistan( the last from February to May 2014) and selected regions of the Russian Federation.The cause of such measures were cases of poliomyelitis caused by "wild" strains of the virus.So, in 2010, according to the WHO in Tajikistan, there were 400 cases of poliomyelitis, and in Russia( in the North Caucasus) - 7. After mass immunization, poliomyelitis in these territories was no longer diagnosed, which allows us to state the effectiveness of the measures taken.

What scares parents in the turf immunization?

Many parents who vaccinate their children according to the calendar are puzzled why their child needs to do additional vaccination.Indeed, the turkey immunization provides for the immunization of all children( of course, if there are no contraindications for vaccination).Therefore, it should be noted that an additional dose of live poliomyelitis vaccine does not pose any danger to a healthy child's organism, on the contrary, its administration promotes the strengthening of local immunity in the intestine.So, in countries where "wild" strains of poliovirus continue to circulate, children are given 10 or more doses of OPV.

Several other questions concern parents whose children have never received polio vaccinations.Especially for such situations in the documents that regulate the conduct of immunization in Ukraine, it is stated that the first vaccination with inactivated vaccine( IPV), and then with OPV, is provided for for babies not previously vaccinated. This reduces the risk of vaccine-associated poliomyelitis, which occurs in one child among 2.4 million immunized.

Another very important problem is the potential danger of children vaccinated with live poliomyelitis vaccine, for others, especially unvaccinated children and pregnant women. For the unvaccinated, the risk does in fact exist theoretically, since after the OPV vaccination, the children within 2 months secrete live poliomyelitis viruses with feces. That is, if a number of hygiene rules are not respected, an unprotected child can become infected with poliovirus, especially if he has chronic ailments and weakened immunity.For pregnant women who were vaccinated against poliomyelitis, the children who received OPV do not present any danger.

In the Russian Federation, the code was used for immunization against poliomyelitis, vaccinated and unvaccinated children were separated for 60 days( quarantine was introduced in children's institutions), and unvaccinated babies were not allowed into kindergartens, which caused a lot of negative responses among parents of unvaccinated children.In Ukraine, this separation is not provided, so all responsibility for the health of children rests with parents who either do not want to vaccinate a child or bring "purchased" medical certificates of vaccination to medical institutions.

"Problematic" vaccine

No less than the fear of the very turkey immunization of parents of young children is concerned about the ambiguous information about the vaccine OPV, which is used for vaccination.According to some "knowledgeable" people, it is the defrosted and re-frozen French vaccine that is used.But the Deputy Minister of Health of Ukraine claims the opposite, that an absolutely different vaccine has been prepared for vaccination now, delivered in the autumn with all the rules of transportation and storage.The "problem" OPV remains in the warehouses and awaits verification.What really happens is hard to say.However, looking at the figures that are on the site of the Ministry of Health, it can be concluded that after all something was brought to Ukraine, since 1.5 million doses of OPV were re-frozen, and 2 were sent to the regions for the first round of immunization, 2 million doses.

Thus, the parents can either trust or distrust officials and always ask the medical staff to demonstrate a thermometer on the vial of the vaccine before the vaccination.On this indicator, the square in the circle should remain light, if it has darkened, then the preparation was exposed to the influence of elevated temperature and is not suitable for use.In conclusion,

• , even if there was no outbreak of poliomyelitis( many discussions are held about the veracity of this information), low coverage of small children with polio vaccination over the past few years is already an indication toMass immunization;
• a live polio vaccine for children was introduced earlier, and these guys always posed a certain danger for the unvaccinated, right now, due to mass immunization, the risk of infection increases somewhat and requires increased vigilance from parents( the development of the habit of washing the hands more often in children,Do not drink from someone else's dishes, do not pull everything in your mouth, etc.);
• parents whose children have not been immunized for some reason should consider that in case of some emergency situations( polio outbreaks, for example) their children will be the first target for this terrible disease.

To the same fathers and mothers who decided to vaccinate their children from poliomyelitis, remember that at the time of vaccination the child must be absolutely healthy, he must be examined by a doctor without fail and vaccination should be carried out only in a medical institution.

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The doctor responsible for questions that may arise from parents preparing a child for polio vaccination is

Zubkova Olga Sergeevna, medical reviewer, epidemiologist