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Polio Do Vaccine Viruses Eliminate Polio?
According to the plans of the World Health Organization (WHO), polio should have been extirpated worldwide, but in recent years there have repeatedly been setbacks in the fight against polio (poliomyelitis, polio for short). This year, however, a historic low is emerging: So far, only 51 cases have been reported to the WHO, according to the statement of the Robert Koch Institute (RKI) for the World Polio Day on 28 October. Significant progress has also been made in the most vulnerable countries, such as Afghanistan, Pakistan or Nigeria, so that there are good chances of eradicating the disease by 2018, reports the RKI.
According to the RKI, the "global polio situation has never been so favorable" as it is now. Last year, there were more than 350 infections. So far in 2015, however, only 51 diseases were reported to the WHO. The eradication (eradication) of the poliovirus seems to be within reach. However, in the "final phase of polio eradication, the oral vaccine that has made significant global successes could jeopardize the final success," warns the RKI. Because the oral vaccine (OPV) with attenuated, but still replicable pathogens, could have the consequence that the vaccine viruses circulate in insufficiently vaccinated populations and even cause acute flaccid paralysis.
An eradication of polioviruses by 2018 seems feasible. (Image: Dr_Kateryna / fotolia.com) Outbreaks due to vaccine viruses
In Germany, since 1998, as well as in other industrial nations, only a so-called injectable dead vaccine (IPV) is used. In many poorer countries, however, the oral vaccine continues to be used. The pathogens are increasingly becoming a problem themselves. For example, since 2000, 24 outbreaks with a total of 786 polio cases have been registered worldwide by so-called circulating vaccine-derived vaccines (cVDPV), "reports the RKI. This year, 14 children from five countries (Madagascar, Nigeria, Guinea, Laos and Ukraine) have already developed poliomyelitis through cVDPV. At the same time, a country from the WHO region Europe was affected by Ukraine.
Strategy change of the WHO
In view of the increased problems with vaccines for the oral vaccination, the WHO has decided to change its strategy. A new strategic plan for the period from 2013 to 2018 has been prepared, "the essential component of which is the worldwide switch from OPV to IPV," reports the RK. By the end of the year, another 120 states are expected to include at least one IPV dose in their routine vaccination program. However, this will trigger a significant increase in demand for vaccines, which, according to the RKI, may also lead to bottlenecks in vaccine supply in Germany.
Successes in Pakistan and Afghanistan
However, in countries like Pakistan and Afghanistan, not only is the difficulty of vaccine care available, but vaccine workers have faced much more serious problems in the past. The ruling Taliban, for example, banned polio vaccination in the Pakistan-Afghanistan border area and accused the vaccination workers of spying on the US, reports the RKI. The vaccinations are an attempt to make Muslims infertile, so another accusation. Their work is life-threatening for the local vaccine workers and according to WHO data, at least 75 employees have been killed by vaccination programs in the past two and a half years.
Today, assistants accompanied by armed security forces in the areas controlled by the Taliban go from house to house and inform parents, reports the RKI. Also, some religious leaders would now support the vaccination programs. "The reduction in the number of cases in Afghanistan and Pakistan is not only significant for the two countries themselves", but to avoid a renewed spread of the pathogens, according to the RKI. Based on the remaining endemic areas, transmissions of wild polioviruses into already polio-free areas have occurred again and again in the past.
Africa soon polio-free?
In Africa's only remaining endemic country, Nigeria, this year's biggest success in the fight against polio has been recorded, according to the RKI. Since July 2014, no more cases of polio have occurred here and the country was removed from the list of endemic countries a few weeks ago. In 2012, Nigeria had more than half of all polio diseases worldwide. The last disease of a wild poliovirus in Africa was reported "in August 2014 from Somalia, the country where the last smallpox disease occurred in 1977," reports the RKI. After another two years without a police case, Africa could become the fifth WHO region to be certified as polio-free. In order to achieve this goal, it would be necessary to close existing vaccinates, especially in the countries affected by Ebola, because planned vaccination campaigns were partially suspended there last year.
Critical storage of polioviruses
On the way to achieving the goal of polio eradication, the so-called laboratory containment of polioviruses is becoming increasingly important, according to the RKI. This includes all measures for the safe use and storage and thus for the prevention of a voluntary or involuntary release of polioviruses from laboratory stocks. From next year, the containment will gradually be extended to polio vaccines. For example, in September 2015, the Global Certification Commission officially declared polypore virus type 2, which has not been detected since 1999, to be eradicated. This declaration forms the basis "for the worldwide cessation of the polio vaccine against type 2 (OPV2) and the use of bivalent polio vaccines (OPV 1 + 3) from mid-2016," reports the RKI. However, before the safe storage of all polioviruses of type 2 (game and vaccine viruses) must be guaranteed.
Vaccine developed 60 years ago
The first polio vaccine was developed by Dr. Ing. Jonas Salk 60 years ago. Therefore, the annual World Polio Day takes place on his birthday. His vaccine was the prerequisite for the successful fight against poliomyelitis. Dr. Albert Sabin had developed a second vaccine in 1961, the oral live vaccine (OPV). According to the RKI, immunizations have achieved remarkable results and 80% of the world's population now live in polio-free areas. Four out of six WHO regions are polio-free. With the reached, historical low of the polio infections the aim of the eradication by the year 2018 seems quite realistic. (Fp)