Inactivated polio vaccine introduction in south Asia—1 year on

Publication History

In 2014, the Global Polio Eradication Initiative advised introducing one dose of inactivated polio vaccine (IPV) in countries not already using it. The introduction of IPV, which contains inactivated forms of poliovirus, aims to mitigate the small risk of mainly type 2 live attenuated poliovirus in the oral polio vaccine (OPV), causing vaccine-associated paralytic poliomyelitis and vaccine-derived poliovirus. In September, 2014, Nepal was the first country supported by GAVI to introduce IPV. Since this launch all countries in south Asia (Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka) have introduced IPV.

After the Nepal launch in 2014, we suggested four challenges that lay ahead:1 communication difficulties with IPV introduced with continued use of OPV; hesitancy or rejection by caregivers due to additional immunisation sessions or injections; ensuring that the supply chain could cope with another vaccine and that the hardest to reach children would benefit; and misperceptions about polio eradication and the need for another type of polio vaccine.

Through careful preparation for IPV introduction in south Asia, these challenges were either overcome or transpired to be less important than anticipated. Communication messaging to caregivers explained how combined OPV and IPV offers the best protection against polio.2 In Pakistan, because of the focus on OPV campaigns and polio eradication, communication emphasised the importance of routine immunisation. In other south Asian countries, efforts were designed to convey the importance and safety of IPV, ensure continued acceptance of OPV, explain benefits of multiple injections in one session, and to engage professional associations, civil society, and religious and community leaders. Countries developed training modules and materials for health workers based on global guidance.3 Context-specific interventions were used. In the Maldives, health workers on remote atolls were trained via teleconferences.4

Although early experiences in Nepal indicated that caregivers might be hesitant about accepting multiple injections during one session, health workers suggested that consistent communication of the benefits of these injections would address concerns of the caregivers. This approach corresponded with existing evidence about positive provider recommendations and parental acceptance of multiple injections.5 Bangladesh introduced an additional session for the pneumococcal conjugate vaccine launched at the same time as IPV, but all south Asian countries added IPV to existing vaccination sessions.

Planning avoided supply chain difficulties from being a major challenge. All countries were required by GAVI to assess the strength of their supply chain before the introduction, and part of the IPV vaccine introduction grant was dedicated to improve the supply chain as needed.

After the Nepal launch we noted media stories that suggested some misunderstandings regarding IPV,1 but these stories did not set a trend. In the lead-up to a country’s launch of IPV, media was effectively engaged and often reporting was scientifically accurate.6, 7

Despite the successful handling of some of the risks, other issues emerged. High coverage of IPV is not secured through a vaccine launch. Given that in most countries IPV will be administered at the same time as diphtheria-tetanus-pertussis (or pentavalent) vaccine, coverage of IPV is likely to be similar to these vaccines, which is low in some parts of south Asia.

Similar to previous new vaccine introductions that did not raise coverage of existing vaccines,8 IPV has not yet been used as an opportunity to increase routine coverage and address gaps in equity, perhaps due to the necessary speed of introduction. WHO undertook a post-introduction evaluation in Bangladesh in December, 2015. When completed, this analysis will be the first insight into IPV use in south Asia and will assist with improvement efforts.

Introduction of IPV was slower than anticipated in some countries. Initially WHO’s recommendation was to discard open vials after 6 h or at the end of a session, irrespective of remaining doses in the vial. However, the policy was later revised so that IPV-containing vials can be used for up to 28 days after being opened.9 In Afghanistan this policy change postponed their introduction because it was decided to wait until delivery of a redesigned vial label. Constrained global supply of IPV due to difficulties in scaling up bulk production and quality control delayed introduction in India. Yet, despite some delays, all the south Asian countries successfully introduced IPV in 2015, as planned.

With IPV introduced, the next step in polio eradication is to switch the type of OPV used in immunisation schedules from trivalent OPV (tOPV) to bivalent OPV (bOPV). This change will remove live attenuated type 2 poliovirus (included in trivalent but not bivalent forms of OPV) and its small associated health risks. The switch is planned to happen on one day between April 17, and May 1, 2016, with remaining tOPV destroyed within 2 weeks.10

South Asian countries have developed plans for the switch encompassing procurement, logistics, communication, and waste management and disposal. Anticipated challenges include ensuring destruction of surplus tOPV and communicating to health workers the dangers associated with its continued use. Vaccine costs for unused tOPV, and regulatory approval for bOPV in routine schedules could also be hurdles that affect the switch.

Introduction of IPV has been successful in south Asia, and many challenges have been overcome. The focus is now to ensure high and equitable coverage of IPV to maximise the benefit of removal of tOPV from routine vaccination schedules in 2016.

The opinions expressed in this paper are solely those of the authors and do not necessarily represent the official position of UNICEF. We declare no competing interests. No funding was received for this Comment, but UNICEF in south Asia receives funding from GAVI for its work on inactivated polio vaccine.


  1. Hasman, A, Raaijmakers, HCJ, and Noble, DJ. Inactivated polio vaccine launch in Nepal: a public health milestone. Lancet Glob Health. 2014; 2: e627–e628
  2. Kim, HJ. WHO global immunization news (GIN): diversifying communication channels but focusing on key messages on IPV introduction in Nepal.; 2014. ((accessed Nov 20, 2015).)
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  6. Salahuddin, T. Introduction of IPV in polio endgame. The Daily Star (Dhaka). July 5, 2015; ((accessed Nov 20, 2015).)
  7. Subba, MB. Injectable inactivated polio vaccine introduced. Kuensel (Bhutan). July 6, 2015; ((accessed Nov 20, 2015).)
  8. Shearer, JC, Walker, DG, Risko, N, and Levine, OS. The impact of new vaccine introduction on the coverage of existing vaccines: a cross-national, multivariable analysis. Vaccine. 2012; 52: 7582–7587
  9. WHO and UNICEF. Application of WHO multi-dose vial policy for inactivated polio vaccine.; 2014. ((accessed Nov 20, 2015).)
  10. Global Polio Eradication Initiative. Update on the OPV switch and short term supply constraints for IPV.; 2015. ((accessed Nov 20, 2015).)
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