“I didn’t know immunization could have saved my child,” Munni Begum reflected. More than thirty years ago, Munni’s infant son, Zulfikar Ahmed, fell victim to polio. Now she volunteers as a ‘change agent’. This involves working in her local community of Moradabad in Uttar Pradesh, where she encourages other mothers to immunise their children and ensures that vaccines and other vital medicines reach them.
Munni’s work is an invaluable part of a large apparatus aiming to keep polio under control in India, where it has been eradicated since 2011. This is a far cry from when Munni’s son contracted the disease.
At that time polio was widespread in India. Immunization campaigns were in their infancy. India’s poorest states, including Munni’s native Uttar Pradesh, were endemic pockets of the disease. There, transmission occurred quickly. Water supplies contaminated with poliovirus enabled the rapid spread of the disease among the crowded towns and villages.
The development of polio vaccines in the 1950s gave the world hope that the disease would soon become a thing of the past. Dr Jonas Salk announced in 1955 what is now known as the inactivated poliovirus vaccine (IPV). This was followed by the introduction of the oral polio vaccine (OPV), developed by Dr Albert Sabin. These landmarks saw polio rates deplete, especially in the western world, from which the disease – once among the planet’s most feared conditions – almost vanished entirely by the turn of the century.
This was not the case in India. Countrywide, numerous factors made the eradication of polio a challenge. The sheer size of India’s population, poor sanitation coverage and great disparities in access to healthcare posed significant obstacles the polio vaccination campaign would have to overcome.
Despite these grim odds, the World Health Organization (WHO) certified India as ‘polio-free’ in March 2011. As India was once considered the most challenging place on earth to end polio, the eradication of the disease there is touted as one of the biggest achievements in global health efforts.
First attempts at eradication
The earliest attempt to isolate poliovirus was by CG Pandit, the first Director of the Indian Council of Medical Research (ICMR). The Expanded Programme on Immunization was started in 1978 – later renamed as Universal immunization Program (UIP) – which provided the OPV to children as part of the programme.
In 1988, India became a signatory to the Global Polio Eradication Initiative (GPEI), committing participating nations to eradicate polio. Before the launch of the GPEI, polio crippled an estimated 200,000 children in India each year.
But despite this commitment, progress was slow, it was nearly two decades before a successful polio campaign began to gain ground in India. Dr Naveen Thacker, past president of the Indian Academy of Pediatrics and a member of the expert advisory group to the Indian government for polio eradication at the time recalled how there was not sufficient action to deliver on this promise.
First success stories
It was only in 1994 when the local government of New Delhi conducted a successful mass immunization campaign — targeting one million children up to three years of age — that the idea began to gain ground that India might actually be able to tackle this disease. Following success in New Delhi, India launched its first nationwide polio immunization campaign in 1995. It held National immunization Days (NIDs) to immunize all children up to the age of five years.
The National Polio Surveillance Project (NPSP) was established in 1997 for poliovirus surveillance through a collaboration between the WHO and the Government of India. This surveillance effort confirmed the last reported global case of wild poliovirus type 2 in 1999 in Aligarh, Uttar Pradesh.
In 2001, UNICEF established the Social Mobilization Network (SMNet) in Uttar Pradesh to mobilise the community for polio immunization and legendary Bollywood movie star Amitabh Bachchan became the UNICEF Brand Ambassador for polio. The efforts of the actor were later acknowledged by Bill Gates as greatly assisting efforts to eliminate polio in India.
The involvement of celebrities was vital in increasing public perception of polio. In 2002 when 1,556 cases of polio emerged in India, the government attempted a media campaign to increase vaccination coverage. The resurgence was significant due to the previous state of decline of polio prevalence in India. In 2001 only 268 cases had been reported, with these limited to two states.
Despite the availability of vaccines, many rural mothers were not approaching the vaccination camps with their children. This may have contributed to a low immunisation rate in some communities and a resultant resurgence of cases of polio. By incorporating public media figures and spreading awareness, immunisation rates once again increased.
In May 2006, the monovalent oral polio vaccine type 1 (OPV1), was introduced, as a targeted intervention at birth in Western Uttar Pradesh. Monovalent OPV1 was recommended because of its greater efficacy against WPV1 when compared with trivalent OPV due to the body focusing antibody production against only one strain.
Challenges faced despite scaling up the polio campaign
One of the challenges faced at the time was the reluctance of parts of the Muslim community to accept the vaccine. Social mobilisation efforts were intensified to gain support from religious leaders, Muslim institutions, mosques and madrasas (schools).
Vaccination and tracking of newborns began in Uttar Pradesh and Bihar and a migrant strategy by 2007 was introduced to immunize children on the move. People moving out of the endemic states with families were identified and immunized in Punjab, Gujarat, West Bengal, Maharashtra, Delhi.
As children who suffered from severe bouts of diarrhoea did not fully benefit from the OPV, community mobilisers started working with parents to promote the need for hand-washing, hygiene and sanitation, exclusive breastfeeding up to the age of six months, diarrhoea management with zinc and oral rehydration therapy as well as routine immunization.
The resurgence of type 3
The use of mOPV1 in most polio rounds had helped reduce type-1 wild poliovirus (WPV) transmission to record low levels. However, in 2009, India experienced an outbreak of type-3 WPV.
WPV exists in three types. Immunity against one type does not mean one is immune to the others. This meant that as cases of type-1 WPV fell, an outbreak of 659 cases of predominantly type-3 poliovirus infections was still able to occur. About eighty percent of them occurred in UP and seventeen percent in the state of Bihar.
The Government of India declared polio a public health emergency. All states and union territories prepared emergency preparedness and response plans to respond to any case of wild poliovirus.
The final case
The last polio case in India was reported in 2011 in a two-year-old girl, Rukhsar Khatun in Howrah, West Bengal. Notably, her two siblings received polio vaccinations. Rukhsar, however, was often sick with diarrhoea and despite encouragement from local health workers, her parents had thought it was safer for her to avoid the vaccine.
In response to the lone case of polio in 2011 in Howrah, a large-scale mop-up immunisation activity was launched within seven days of notification of the case. This targeted action worked and India was finally removed from the list of polio endemic countries after completing a year without reporting any case of polio in January 2012.
This final case of polio in the nation is a testament to the fact that any gaps in immunisation can allow cases of the disease to occur.
According to the then Minister for Health and Family Welfare, Ghulam Nabi Azad, “this achievement was made possible with the indigenous bivalent polio vaccine, adequate domestic financial resources and close monitoring of polio programme, with which immunization levels soared to 99 percent coverage and allowed India to achieve polio eradication.”
Azad also noted the overwhelming efforts of a colossal team of grassroots workers. “A 2.3 million strong team of polio volunteers and 150,000 supervisors worked day and night to reach every child.”
The endgame strategy for polio involves a switchover from the OPV to the IPV. While OPV has been a successful tool in the eradication of polio, the global health community believes a switchover to the IPV is needed to put the final nail in polio’s coffin.
In 2009, there were fifteen cases of vaccine-derived poliovirus infection. Vaccine-derived infections are a significant pitfall of the OPV, as it uses a weakened strain of the poliovirus to replicate in a recipient’s intestines. The objective is for the host to produce antibodies against the virus. This usually produces no symptoms. However, in rare cases, the OPV can cause vaccine-associated paralytic poliomyelitis – identical to that caused by the original poliovirus.
While the risk is small, it is not one the world can afford to take when it is in the endgame against polio. In India, many of the issues that plagued polio eradication efforts are still of concern. Poor sanitation coverage and lack of access to healthcare in many rural areas are still major concerns. If vaccine-derived polio cases do occur, it could potentially result in a resurgence of polio on a larger scale.
Vaccine-derived cases do not occur when using the IPV. The IPV contains all three serotypes of polio. These strains have been killed off using formalin, preventing any future mutation and so do not present any possibility of future infections.