Public Health Polio Eradication in Pakistan
by
Zulfiqar A. Bhutta, Muhammad Atif Habib, Sajid Bashir Soofi
  • LAST MODIFIED: 30 March 2017
  • DOI: 10.1093/obo/9780199756797-0158

Introduction

Poliomyelitis (polio) is a viral infection that spreads primarily through the fecal-oral route and usually affects children younger than five years of age. After ingestion, the virus multiplies in the intestines and spreads to the nervous system from there, eventually leading to paralysis. Irreversible paralysis is seen in approximately one in every two hundred children that are infected. This paralysis proves fatal in approximately 10 percent of cases when respiratory muscles are involved. Currently, no cure exists for poliomyelitis; however, there are vaccines available which have been successful at significantly reducing the prevalence of this debilitating infection across the world. With a successful vaccination program since 1988, the number of paralyzed persons due to polioviruses has decreased by over 99.9 percent. However, the disease still presents a real threat, especially in Pakistan; this bibliography focuses on the challenges of eradicating disease in this region in particular.

Epidemiology

The epidemiology of polio relates a story of the success of effective vaccination programs. In 1988, there were around 350,000 cases of polio across 125 countries. The goal to eradicate polioviruses worldwide was adopted in 1988 and since then the number of paralyzed persons due to polioviruses has decreased by over 99.9 percent. In 2014, the World Health Organization (WHO) reported 359 cases of paralytic poliomyelitis due to wild polioviruses worldwide (Cases of Wild Poliovirus by Country and Year). In the end of 2015, the remaining endemic areas with wild poliovirus circulation were limited to security-compromised parts of Pakistan and Afghanistan and in Nigeria. In Nigeria, no new cases of polio were reported in 2015, and in September of that year was removed from the list of poliovirus endemic countries (WHO Removes Nigeria from Polio-Endemic List), however the virus emerged again in mid-2016 (Cases of Wild Poliovirus by Country and Year). Despite the dramatic reduction in cases of poliomyelitis, it is proving difficult for the Global Polio Eradication Initiative (GPEI) to finally complete the eradication by interrupting the last chains of transmission in these endemic areas; and export of wild polioviruses from the endemic areas into polio-free countries have occurred in multiple occasions, sometimes causing large outbreaks of poliomyelitis (Hagan, et al. 2015). Polio cases can also be divided into groups by the infecting organism. A majority of the patients reported were infected with the wild poliovirus while only a few were positive for the vaccine-associated poliovirus. The wild poliovirus is the form of the virus found in nature and had three subtypes, one of which was declared extinct in 1999. In contrast, the vaccine-associated form of the virus develops when the attenuated form of the virus that is used for vaccination mutates during replication. However, this is extremely rare and it is estimated that when receiving the first dose of the oral polio vaccine, one in every 2.7 million children develops paralysis. Generally, vaccine-associated strains of the poliovirus do not transmit between hosts as easily as the wild type. However, in certain conditions in severely under-immunized populations the vaccine-associated form of the virus can begin circulating in the community with low herd immunity. WHO reported thirty-two wild poliovirus cases by late 2016 with sixteen cases from Pakistan, twelve cases from Afghanistan, and four cases from Nigeria. Data divided by country for the incidence of polio in 2016 shows that the majority of cases were found in Pakistan and Afghanistan. The difference in incidence rates between Pakistan and other countries highlights the need for a much more effective prevention program in Pakistan. Although the incidence of polio for the year 2016 decreased in Pakistan, there is still a large amount of room for improvement until the last case stands (see the WHO’s Poliomyelitis Fact Sheet, cited under Global Polio Eradication Initiative).

Global Polio Eradication Initiative

The Global Polio Eradication Initiative (GPEI) was first launched in 1988 with four key partners: the World Health Organization (WHO), Rotary International, the United Nations Children’s Fund (UNICEF), and the US Centers for Disease Control and Prevention (CDC). The program received support from governments across the world and from international welfare organizations such as the Bill & Melinda Gates Foundation. The success of the GPEI is evident when examining the decrease in the incidence of polio since the inception of the eradication initiative. The number of polio cases across the world has decreased by 99 percent between 1988 and 2014. The triumph against polio has been gradual but steady, with the WHO Region of the Americas being declared free of polio in 1994. The Western Pacific Region as demarcated by the WHO was cleared of polio in 2000, followed by the European Region in mid-2002. In the first quarter of 2014, the WHO region of South East Asia was declared polio free. According to WHO, Pakistan is classified as part of the Eastern Mediterranean Region which is yet to be cleared of polio. Perhaps the greatest achievement of the GPEI is that currently 80 percent of the world’s population is living in areas that have been certified as polio free. There are over 10 million people today who have been saved from paralysis by the successful polio vaccination program. That in itself is a fact that is worthy of great appreciation; however, the continued success of these programs is contingent on the complete eradication of polio from countries that are still affected by this disease (Poliomyelitis Fact Sheet). Given the ongoing poliovirus circulation and a threat of reemergence of the disease, a polio eradication and endgame strategic plan 2013–2018 was introduced in 2013. This plan has four core objectives which are: to detect and interrupt all poliovirus transmission; to strengthen immunization systems and withdraw oral polio vaccine; to contain poliovirus and certify interruption of transmission; and finally to plan polio’s legacy (Global Polio Eradication Initiative). A major focus outlined in this strategic plan was the ultimate withdrawal of oral polio vaccines (OPV) from all immunization programs globally in a phased manner to mitigate the risks associated with vaccine-derived polio and the immunity gap after type 2 withdrawal and the recommendation of introducing inactivated poliovirus vaccine brought forward (Estivariz, et al. 2013; Patel, et al. 2015; and Garon, et al. 2016).

Polio Vaccines

One of the major reasons for the success of the polio vaccination program is the oral polio vaccine, which was developed by Albert Sabin in 1961. This trivalent vaccine protects against all three strains of the wild poliovirus, one of which has now been declared extinct. In 2016 this trivalent vaccine was replaced by a bivalent oral polio vaccine and trivalent oral polio vaccine is no longer available. The major advantages of this vaccine include the fact that due to oral administration, vaccine teams can consist entirely of volunteers and do not require experienced professionals or sterile injections. This factor also decreases the cost of the vaccination program and makes large-scale programs far more feasible. An additional advantage of the oral vaccine is that it allows for the concurrent administration of oral vitamin A supplementation. This has helped avoid the deaths of approximately 1.5 million children, in addition to the lives saved by polio vaccination (Blume and Geesink 2008; GPEI 2016). The major disadvantage of the oral polio vaccine is that since it is a live vaccine, it can lead to vaccine dependent poliomyelitis in a very small percentage of those who are vaccinated (Platt, et al. 2014). The neurovirulent virus is referred to as vaccine-derived poliovirus (VDPV) and usually has three categories, namely: circulating VDPVs (cVDPVs), immunodeficiency-associated VDPVs (iVDPVs), and ambiguous VDPVs (aVDPVs). Additionally another rare event is vaccine-associated paralytic poliomyelitis (VAPP), a rare event which is associated with oral polio vaccine (OPV) administration, which is caused by a strain of poliovirus that has genetically changed in the intestine from the original attenuated vaccine strain contained in OPV (WHO 2016; Sutter, et al. 2013; Diop, et al. 2015). Additionally, in case of a mutation in a community with low herd immunity the mutated vaccine-derived virus can start circulating in the members of the community and cause polio in unimmunized individuals (John and Jayabal 1972). A bivalent and monovalent alternative of the oral polio vaccine was developed after the eradication of the type 2 strain of the virus. This is more effective than the original trivalent oral vaccine and also offers all the advantages of the original (Sutter, et al. 2010; el-Sayed, et al. 2008). In contrast, the inactivated polio vaccine does not carry any risk for vaccine-dependent poliomyelitis although inactivated polio vaccine (IPV) recipients may get infected but they will not get paralyzed because they are protected against invasion of the central nervous system. However, IPV is more expensive and requires administration via injection by trained health workers. Furthermore, the inactivated vaccine does not confer strong intestinal immunity which means that individuals who ingest the virus will not get infected but can still transmit it to other members of their communities. However, recent studies have demonstrated that IPV can boost both humoral and mucosal immunity and can be used effectively to reduce the immunity gap (John, et al. 2014; Jafari, et al. 2014; and Habib, et al. 2016).

Pakistan and the EPI

Focusing on the situation in Pakistan, numerous efforts have been made to counter the polio epidemic. The Expanded Program on Immunization (EPI) was first launched over thirty years ago and has dramatically changed the healthcare landscape in Pakistan since its inception. As per the latest report from the Pakistan Demographic Health Survey (PDHS) that was published in 2013, 54 percent of Pakistani children received all their basic vaccinations. This includes one dose of the oral polio vaccine at birth and three subsequent doses at the age of six weeks, ten weeks and fourteen weeks. Looking specifically at polio vaccination rates reported in the PDHS, 85 percent of children received all doses of the polio vaccine in 2013 (Pakistan Demographic and Health Survey). This is an encouraging figure since polio vaccine coverage has seen an almost hundred percent increase from 43 percent in 1990. Polio transmission in Pakistan is not rampant across the country; in 2015 it is limited to 11 of the 152 districts in the country. The three prime areas that need to be targeted in polio eradication programs are the city of Karachi, Quetta and its surrounding areas, and the adjoining regions of the Federally Administered Tribal Areas (FATA) and the Khyber Pakhtunkhwa province. A major problem in the last of the aforementioned regions is that they lie on the Afghanistan border where there is a large amount of unchecked cross border traffic. This leads to residents of each country repeatedly reinfecting each other and compounds the problem of polio eradication in the area. Due to the nature of the disease and risk of further spread from Pakistan into other countries that have already eradicated polio, a national emergency was declared for the interruption of polio transmission. As part of this emergency, a National Emergency Action Plan for Polio Eradication was launched in 2011 with the aim of limiting polio transmission. The plan has been revised three times so far, with the latest revision being published in 2015. Each revision is edited to adapt to the current situation and to increased coverage based on lessons from previous efforts. The original plan focused primarily on a federal effort whereas revisions have increased provincial and district level involvement.

Security and Other Issues

A significant challenge for polio eradication in Pakistan is the history of violence against vaccination teams. Multiple attacks have been carried out against vaccinators who were visiting at-risk populations as part of the polio eradication action plan. These attacks have led to the loss of the lives of healthcare professionals and significantly compounded the problem (Masood 2015; Ali 2014; and CBS News 2012). The threat of violence has become a significant deterrent to vaccination campaigns. Volunteer administration was the original strength of the oral vaccine; fear for personal safety has drastically reduced the number of volunteers. Vaccination campaigns that were initially organized to maximize awareness are now kept at a low profile to ensure the safety of volunteers. Not surprisingly, the areas where violence against vaccinators has been reported most frequently are also the areas where polio transmission is rampant (Bhutta 2014, Bhutta 2013). Another major issue facing the polio vaccination program is the negative representation by those opposing it. The negative image creates insecurity in those who are most susceptible, by labeling vaccination programs as a conspiracy of “Western powers” and using hollow Islamic logic to deter the masses from vaccinating their children (Fetene and Sherani 2014; Shah, et al. 2011). Efforts have been made to work against these perceptions and use the relevant forums to encourage vaccination. Local celebrities have been used as ambassadors for polio vaccination in order to challenge the idea of vaccination being a Western conspiracy. Similarly, vaccination has been endorsed and encouraged by religious scholars and these messages have been propagated through different mediums to reach the maximum number of people (Daily Times). Other steps include integrating polio vaccination with the remainder of the Expanded Program on Immunization (EPI) vaccinations and other preventive health measures in awareness messages so that polio eradication is not singled out as a particular agenda. Another step in the same direction is the creation of community platforms in both social and professional settings to propagate the message without gathering unnecessary attention.

Vaccine Refusal

Vaccine refusal is another major problem that has been highlighted since the inception of the National Emergency Action Plan for polio eradication (Khan and Ahmad 2015). Recently reported as 0.14 percent of the target population, the refusal rate for polio vaccination is not very high in Pakistan. However, the issue arises from the fact that most of these refusals are grouped together in areas with high transmission such as Karachi and Khyber Pakhtunkhwa (National Emergency Action Plan for Polio Eradication, cited under Pakistan and the EPI). These are the areas that suffer from high polio transmission (Murakami, et al. 2014). Vaccine refusals usually do not constitute a great healthcare problem due to the presence of herd immunity. However, in such areas where vaccination is already low, refusals further increase the transmission rate. In 2013, 10 percent of the reported polio cases belonged to families that had previously refused vaccination. Social mobilization with community teams is an extremely effective method to decrease the refusal rate. However, with the current security situation and the history of attacks in areas that have both high refusal and transmission rates, social mobilization is not a viable option. These reasons create massive hurdles on the path toward complete polio eradication in Pakistan.

Lessons from Other Countries

While Pakistan currently seems to be in a dire and incredibly complex situation with respect to polio eradication, India was in a similar situation not very long ago. With one of the largest populations on the planet, polio eradication in India seemed almost impossible. Severe poverty and limited access to certain regions further complicated the struggle against polio in India. However, by mobilizing resources from all levels of government and the healthcare industry, India managed to completely stop polio transmission (John and Vashishtha 2013). Initiatives taken by local agencies and strong support from international organizations made polio eradication possible in India (GPEI 2014). A focused problem-solving approach toward polio eradication was a great catalyst in these efforts. A focused approach with strong direction and political will were some of the most important factors that led to polio eradication in India. The last polio case from India was reported in 2011 and the World Health Organization (WHO) South East Asia region was declared polio free in 2014 (WHO 2014). India has since then served as a lesson and an inspiration for other countries that are still unable to eradicate polio. The story of polio eradication in Bangladesh is entirely different from that of India. As one of the most densely populated countries in the world, Bangladesh posed an enormous challenge in the efforts to limit polio transmission. The major factors behind the successful eradication of polio in Bangladesh were the effectiveness of the Expanded Program on Immunization (EPI), extensive social mobilization, and strong political will. These efforts made it possible for Bangladesh to completely stop polio transmission by the year 2000, fifteen years after the introduction of the EPI in Bangladesh. However, polio re-emerged in Bangladesh in 2006 after it was spread from India where polio transmission was still frequent at the time. The impressive nature of the healthcare efforts throughout the polio eradication campaign became apparent at this time. Within six months of the first case being reported in 2006, Bangladesh was once again able to stop polio transmission. This was possible through swift and extremely effective measures including multiple immunization days within a matter of months. The method by which polio was eradicated in Bangladesh highlights that the EPI can be a very effective tool when combined with the right initiative and a novel approach.

Strategies and Next Steps

In the efforts against polio, Pakistan seems to be up against insurmountable odds. Though India and Bangladesh offer many lessons, the fact remains that Pakistan is unique. The security situation is a constant threat to those who offer their services to help limit polio transmission. Fringe religious groups are still a significant problem since they encourage vaccine refusal and promote anti-vaccine conspiracy theories. Though the story of polio eradication in Bangladesh is an inspiring one, the strategies implemented in India are more useful in regard to Pakistan. By developing a new model based on the Indian approach it is possible to tackle the polio problem in a manner different than the one that has failed the country previously. The National Emergency Action Plan for Polio Eradication (cited under Pakistan and the EPI) which commenced in the year 2015, provided the strategic directions which underscore the importance of effective vaccination efforts combined with monitoring and surveillance. The NEAP emphasizes the following: the importance of increasing the quality of all polio eradication activities; increasing programmatic access and reach; placing frontline workers at the center of the polio eradication initiative; expanding continuous community-protected vaccinations; ensuring integration of planning and implementation of operations; ensuring security and communications; monitoring of performance and increased accountability at all levels; reviewing and enhancing acute flaccid paralysis (AFP) surveillance sensitivity and quality; enhancing seroconversion through targeted IPV introduction; and expanding and implementing the outbreak response strategy. The important ingredient in the recipe for success is the availability of help from international organizations in polio eradication programs. Backing from these powerful health agencies was one of the key factors that helped limit polio transmission in India and Bangladesh. Though this help has been made available to Pakistan, the lack of strong local leadership and consolidated effort made significant progress unlikely. However, support has been offered to the provincial government for the latest initiative in Khyber Pakhtunkhwa by the Bill & Melinda Gates Foundation. A strong and effective partnership between the local government and resourceful international organizations can go a long way in solving the polio problem in Pakistan. However, the leadership must bear in mind that without an effective strategy and a focused group of critical thinkers these efforts may once again be doomed for failure. Pakistan has the resources to tackle the problem; however, it needs to mobilize those resources in an effective manner and local leaders need to go the extra mile in order to bring an end to polio in Pakistan. Further, after the recent Strategic Advisory Group of Experts (SAGE) recommendation for the introduction of IPV in the routine immunization program. It is imperative to develop innovative strategies to enhance delivery of vaccines through the health system thereby strengthening routine immunization to gain maximum coverage. Although poliovirus circulation has been stubborn, it is confined to some distinct geography, and with a concerted effort and innovations it can be tackled effectively (Bhutta 2014, Bhutta 2013).

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