The strange case of polio delta

Stool samples of affected children were sent to the National Institute of Hygiene Rafael Rangel, Caracas, National Referral Institution, which isolated and typified Sabin type 3 poliovirus in the country. one of the samples, which could be expected in populations immunized with the oral vaccine, which contains the attenuated strains 1 and 3 of the poliovirus. PAHO received an informal report, through the Regional Contact Point for the International Health Regulations on the Detection of Poliovirus mentioned above, and forwarded it to WHO (7 June 2009). 2018). On June 8, WHO published an epidemiological report with updated information (Ref 2), which confirmed the presence of poliovirus in children. For confirmation purposes, the samples were sent to a regional reference laboratory, not identified in the report.

The unofficial report received by the WHO PAHO was promptly disseminated by the Venezuelan Red Society We defend the national epidemiology through a statement, using the right to inform and to alert the public. It was also mentioned that the Venezuelan Ministry of Health was aware of the case, had reserved the information and had not notified the finding to WHO within 24 hours, as established by the Health Regulations. international.

The impact of this information on the public was immediate: polio reappears in Venezuela! Underlined, it has been broadcast by international news agencies with the monotony characteristic of its comprehensive information processing, faithfully followed by Venezuelan agencies and media, with little or no further in-depth study on the subject. This columnist also joined the opinion block, in a digital press article focusing on the regime's responsibility in the current Venezuelan health crisis (Ref 3).

Further development

The overall result of the analyzes carried out Samples sent to an unidentified regional reference laboratory, for confirmation, were published in a report by PAHO / WHO, Washington, DC June 15, 2018 (Ref 1). It was announced that laboratory tests excluded the presence of wild poliovirus and the oral vaccine derivative (abbreviation VDPV) provided to the delta population, so that there would be no spread or damage. Polio epidemic. With him the initial tumult was disarmed. Venezuela was always free of polio!

The report also indicated that the reference laboratory would perform genetic sequencing and add something about the genetic mutation of the vaccine virus.

Was the erroneous finding justifiable?

It is obvious that it is necessary to research and explain why the health authorities involved in the coverage and monitoring of the situation in Delta Amacuro have come to an erroneous conclusion, including l & # 39; PAHO. That's the strange thing about the case. The confluence of several factors indicates this: a) the detection of PFA, b) the child without vaccination history and c) the presence of Sabin PV3 poliovirus in their excrement, which apparently guided the health authorities towards what seemed obvious and in that sense decided, faced with the pressure of the delicate health situation that they faced. They found themselves facing a bioethical location typical of the risk / benefit assessment and the application of the precautionary principle.

If the child had not received the oral vaccine, why was the poliovirus present in his stool? A few weeks before the PFA was detected in the child, the oral vaccine was given in the same community. Polioviruses (wild and incorporated in the oral vaccine) are known to multiply in the gastrointestinal tract, to undergo mutations that tend to restore their original neurovirulence, to replicate (multiply), to excrete and to disperse in the body. population. Probably, the child acquired PV3 poliovirus as a result of this vaccination, through the fecal-oral route, which coincided with the development of PFA.

Genetic sequencing (or rather nucleotide sequencing?) Is a powerful tool for molecular analysis in the hands of experts, who should have received more accurate information in the WHO report, on this topic. which was done in the sample (oligonucleotide mapping, PCR amplification – chain amplification by the direct detection of viral RNA in clinical samples and serves to differentiate between a similar method or another) . It has not been reported where the results and conclusions of nucleotide sequencing could be accessed, so that the Global Polio Eradication Initiative (GPEI) should be considered as a driving force for global polio eradication which appears to be the group that funded the analyzes, as in the updated report of the WHO (ref.1)

This analytic tool has made a decisive contribution to clarifying and dispelling the problem. But the question of the PFA cause remains unresolved. Would it be too bold to think that it could never be known?

Some Basic Academic Information

The intention of this columnist is to present the reader with a brief additional information to facilitate their understanding of the important subject discussed which we hope will be tolerated

• The poliovirus, the causative agent of poliomyelitis, has a single – stranded and positive ribonucleic acid (RNA) genome, of a length of about 7,500 nucleotides, surrounded by a protein capsule (capsid); The detection of the composition and the ordering of these nucleotides is called sequencing. It is one of the best characterized viruses, very useful as a model for the study of the biology of RNA viruses
• The poliovirus has 3 serotypes (PV1, PV2 and PV3), all extremely infectious. PV2 was declared extinct in 2015 and is not listed in the current oral vaccine.
• The only known natural host and reservoir of poliovirus is the human species, which would facilitate its control and extinction through vaccination. The remarkable efforts of Salk and Sabin, half a century ago, to produce the two types of known vaccines currently in use were directed there. In endemic areas, poliovirus is detectable in wastewater and in the environment, it remains active for several weeks to spread. In humans, it spreads fecal-oral and through contact with water and food, especially in areas with low resources and poor sanitation.
• The poliovirus multiplies in the intestine, empties into the blood and spinal cord (anterior motor horns) and the brain, which can lead to known paralysis.
• Faecal detection of poliovirus is effective at about 80% if it is practiced in the first two weeks of the initial infection of the disease.
• The oral vaccine is designed with genetic characteristics to provide maximum immune efficiency and minimal virulence in the vaccinated patient. But the poliovirus RNA in the vaccine can undergo mutations (alteration of the nucleotide sequence, estimated at 1% per year), which can restore its wild virulence, so that the people who receive it can transmit it to d & # 39; Others or acquire chronic or acute infections. In other words, it is genetically unstable. This could lead in the future to a number of cases of virus circulating in the oral vaccine exceeding the number of cases with the wild virus, which, according to experts, suggests to suspend the use of the oral vaccine as soon as possible. that he is safe. Since 1998, vaccines have been administered in Europe using vaccines injected with the killed virus (Salk), which prevents transmission. The famous Robert Koch Institute in Germany has stopped recommending oral vaccination
• However, it should be noted that worldwide, polio cases have decreased considerably, from 350 000 in 1988 to only 37 in 2016, having been avoided around 16 million, thanks to vaccination campaigns planned and supervised by the WHO, within the framework of the objectives of the IMEP.

The Ministry and the Medical Association

The Venezuelan Medical Association has been very clear and timely.As stated at the beginning of this text, the contents of the report sent to the & 90 [[[[[[[[[[[[[[[[[[[[WHOwaspublishedbytheVenezuelanSocietypublichealthandnetworkadvocatefornationalepidemiologyMinisterialsilencewascensoredbyhidinginformationaboutthereoccurrenceofthepoliovirusandbynotinformingtheWHOtowhichheisobligedThisbehaviorchampionedbythethenMinisterofHealthwasconsistentwiththestrategyofmisinformationoftheVenezuelanregimeeveninsuchadelicatematter

The specialists of this union reported that between 2008 and 2017, about 2 million people had accumulated. children at risk of not being vaccinated in a timely manner, which breaks the health programmatic line and shows the irresponsibility of the scheme.

According to Jaime Torres, Board Member of the International Society of Infectious Diseases, the deltana population is one of the most "It is necessary to maintain high levels of vaccination in all countries, before polio does is eradicated in the world ", according to Spanish specialists.

It should be mentioned that low vaccination rates are also partly responsible for the resurgence of diphtheria and measles in Venezuela. Currently, many hospitals lack vaccines. To contain the resurgence of these diseases, the regime will have to act quickly to immunize the population and improve their general conditions of life and health.

Brief Final Examination

Polioviruses derived from the oral vaccine can circulate in humans for many years. years, without being detected. This could encourage health authorities and the informed public to believe, wrongly, that they have been eradicated. If vaccination campaigns are neglected, these circulating polioviruses may lead to the reintroduction or reappearance of polio. For this reason, if the oral vaccine continues to be used, polio will not be eradicated in Venezuela. The case of Delta Amacuro is an early warning.

References

(1) https://www.paho.org/hq/index.php?option=com_docman&task=doc_view&Itemid=270&gid=45364&lang=fr

(2) http: // www.el-nacional.com/noticias/columnista/los-crimenes-narcotirania-venezolana_244336

(3) https://www.paho.org/hq/index.php?option=com_content & view = article & id = 14445 & Itemid = 1926 & lang = en

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