Poliomyelitis is an acute communicable disease caused by wild-type poliovirus. According to WHO, in the pre-vaccine era when poliovirus was the leading cause of permanent disability in children, virtually all children became infected by polio viruses, with, on average, 1 in 200 susceptible individuals developing paralytic poliomyelitis. In 1988, when the annual global burden of paralytic poliomyelitis was more than 350,000 cases, the WHO resolved to eradicate poliomyelitis by the year 2000 and the Global Polio Eradication Initiative (GPEI) was established. Worldwide, sustained use of polio vaccines since 1988 has led to a precipitous drop in the global incidence of poliomyelitis by more than 99% and the number of countries with endemic polio from 125 to just three. Despite the overall success of the GPEI, in 2014, Nigeria, Pakistan and Afghanistan remain endemic for transmission of poliovirus.
Polio vaccination has been part of the Expanded Program on Immunisation by WHO, which all WHO member countries follow. Among these countries, Iran started polio vaccination through its national immunisation program in 1984 and according to WHO, no polio cases have been confirmed in the country since 2001. However, Iranian authorities are worried about cross-border transmission as the disease is still endemic in two neighbouring countries- Afghanistan and Pakistan.
On June 15, Iranian health and medical education officials offered free polio vaccines to Pakistan in a meeting with their federal health services minister. Iran also proposed health centres to be set up on both sides of the border between the two countries to prevent the transfer of communicable diseases such as polio and malaria. The Pakistani response to these offers has been positive and the National Health Services minister of Pakistan said that lessons could be learnt from Iran’s healthcare system and its polio eradication campaign.
There are two types of vaccines that protect against polio: inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV). OPV has been the vaccine of choice for controlling poliomyelitis in many countries and for the global polio eradication initiative. This choice stems from its ease of oral administration, its superiority in conferring intestinal immunity in immunologically naive individuals, and its low cost. Vaccination with OPV is done through 4 doses, which are administered at 2 months, 4 months, 6-18 months, and 4-6 years.
The only adverse event associated with OPV use is vaccine-associated paralytic poliomyelitis (VAPP), which may occur in vaccine recipients or their contacts. The overall risk of VAPP – a temporary form of paralysis – is estimated at 1 case per 2.4 million doses administered. Outbreaks of polio due to circulating vaccine-derived polioviruses continue to be detected occasionally, mainly in areas of low immunisation coverage. WHO recommended that all countries currently using only OPV add at least 1 dose of IPV to the schedule by the end of 2015. The planned universal introduction of IPV is likely to substantially decrease the global VAPP burden by 80%–90%.
In the previous year, ended March 2016, Iran imported IPV for the first time with the goal of reaching the global target. Presently, at least one dose of IPV is administered to Iranian babies as all four doses are unaffordable, given the high costs of the vaccine which is around two dollars per dose.
For the time being OPV is preferred in Afghanistan and Pakistan due to easy administration and with it not requiring sterile syringes. Pakistan and Afghanistan are considered one epidemiological block in terms of polio, because of genetic relationships and epidemiological links between the wild type 1 poliovirus isolates in the two countries. Iran health minister Hassan Ghazizadeh Hashemi says that Iran has the infrastructure to produce sufficient polio vaccine to meet the domestic needs of immunisation programmes and also for people in the neighbouring countries. Iran is also committed to producing IPV to a level that meets domestic needs as well as that of the two eastern neighbours within the next two years. Every year Pakistan requires 40-50 million doses of polio vaccines. The country can get major relief if Iran contributes the expected 4-5 million vaccine doses.
In order to achieve this target, a memorandum of understanding (MoU) was signed between IPI and the pharmaceutical company, Shafa Darou, which will produce the IPV. The initial investment for the production of IPV has been estimated to be about $7.5 million. As Iran shares a 2000 km border with Afghanistan and Pakistan, Iran’s task in producing polio vaccine and its eradication makes the battle against the disease a win-win proposal, although this has yet to be officially acknowledged by the WHO website.