With the world on the cusp of poliovirus eradication, the finding of a case of wild-type poliovirus 1 (WPV1) in a 4-year old child from Lilongwe, Malawi in November 2021 and reported in February (
WHO-AFRO 2022
) has come as a blow and in some respects, as an opportunity. In a statement released on February 17, 2022, the Malawian Ministry of Health confirmed the case and declared a public health emergency (WHO-AFRO. Malawi declares polio outbreak. 2022. https://www.afro.who.int/news/malawi-declares-polio-outbreak 27 February 2022).
WHO-AFRO 2022
). Immediate investigations have been initiated, and no evidence of community transmission is presently discernible. In a statement also released on February 17, 2020, the Global Polio Eradication Initiative (GPEI) indicated that the virus is genetically related to a 2019 Pakistani isolate from Sindh Province, as evidenced by sequencing done at the South African National Institute for Communicable Diseases, with sequencing and phylogenetic analysis confirmed by the Centers for Disease Control, Atlanta, USA (WHO-AFRO. Malawi declares polio outbreak. 2022. https://www.afro.who.int/news/malawi-declares-polio-outbreak 27 February 2022).
Global Polio Eradication Initiative 2022
).Global Polio Eradication Initiative. GPEI statement on WPV1 in Malawi. 2022. https://polioeradication.org/news-post/gpei-statement-on-wpv1-in-malawi/ 27 February 2022).
This report is a disappointing development in global polio eradication efforts, to the continent and to the region. Certification of global polio eradication can only be achieved if wild-poliovirus is shown to be absent from cases of acute flaccid paralysis (AFP, suspected for polio), healthy individuals, or environmental samples in all World Health Organization (WHO) regions for a period of at least 3 years in the presence of high-quality, certification-standard surveillance (
Smith et al., 2004
). In the last 12 months, cases of wild-poliovirus have been confined to the Middle East (Afghanistan and Pakistan) (Global Polio Eradication Initiative 2022
). Before that, the last wild-type poliovirus was detected in 2016 in Borno state in Nigeria, an area plagued by social instability with consequent low vaccination coverage (Global Polio Eradication Initiative. Polio this week as of 23 February 2022. 2022. https://polioeradication.org/polio-today/polio-now/this-week/(accessed 27 February 2022.
Khan et al., 2018
).Africa was certified polio-free in 2020 by the African Regional Certification Commission (ARCC), following concerted socio-political intervention, and robust vaccination campaigns in northern Nigeria eradicated WPV in 2016 (
Khan et al., 2018
, Global Polio Eradication Initiative 2021
). The last case of wild-type polio was identified in Malawi in 1992, (WHO-AFRO 2022
) and the country was certified polio-free in 2005. The national polio surveillance program attained targets of 2 non-polio AFP cases of 100,000 from 2015 to 2019 and achieved an average of 79% stool adequacy over 2012–2019 (WHO-AFRO. Malawi declares polio outbreak. 2022. https://www.afro.who.int/news/malawi-declares-polio-outbreak 27 February 2022).
Manyanga et al., 2020
). In 2020 and 2021, during the COVID-19 pandemic, Malawi reported 125 (1,56/100,000 person < 15 years of age) and 165 cases of AFP (2,16/100,000 person < 15 years of age), respectively, with a stool adequacy rate of 88% (WHO 2021
) and 74%, (WHO 2022
) respectively. If this Malawian isolate is found to be circulating in the community, the WHO-AFRO region is likely to lose its polio-free status, and continental eradication will be set back by 3 years.WHO. AFP/Polio data. 2022. https://extranet.who.int/polis/public/CaseCount.aspx (accessed 27 February 2022.
Investigations including determination of the travel history of the case, laboratory testing of contacts, and retrospective review of hospital records for non-reported AFP cases are ongoing. Although public release of that data is awaited, importation from Pakistan or Afghanistan remains the most logical though unlikely scenario, given the low intensity of direct travel and trade between the Middle East and Malawi (
World Bank 2022
). The best hope is that this finding represents an early detection in Malawi following recent arrival of the strain on the continent. However, importation may have occurred into the East African region months before detection, (World Bank. World Integrated Trade Solution - country profile Malawi. 2022. https://wits.worldbank.org/CountryProfile/en/Country/MWI/Year/LTST/Summary 27 February 2022).
Burkholder et al., 2021
) given the global impact of the redirection of polio resources to combat the COVID-19 pandemic (Global Polio Eradication Initiative 2020
).Yet the detection of WPV1 in Malawi may also be considered an opportunity in 2 respects, namely, to reflect on and revise the newly released polio eradication strategy, and second, to use this event to focus political will in a context where enthusiasm and commitment to polio elimination efforts are flagging.
The first goal of the recently released WHO polio eradication strategy is to permanently interrupt WPV transmission in endemic countries, named as Afghanistan and Pakistan (
Global Polio Eradication Initiative 2021
). Even in its tabulated identification of risks, the strategy did not consider the possibility of exportation nor undetected circulation of WPV outside of these 2 countries. This event, now realized by the isolation of WPV in Malawi, was unforeseen, and highlights the immense effort required to sustain global polio immunity and AFP surveillance. As COVID-19 has taught us, we cannot be complacent while disease events are apparently localized in other parts of the world.The detection of WPV in Malawi, therefore, invites a reflection on the elimination strategy. Can we sustain immunity levels to prevent the re-emergence of polio, given the risk of international transmission? Some have postulated that the GPEI decision to remove OPV2 led to the reduction of population immunity to PV2 and created conditions possible for the emergence of cVDPV (
Chumakov et al., 2021
). The proposal by Chumakov et al (Chumakov et al., 2021
), that the elimination strategy include a strategic objective to maintain high levels of population immunity against all PV serotypes rather than withdrawal of antigens from vaccination programs, is all the more compelling in the light of the Malawi isolate.Regarding maintaining surveillance quality, there is a real risk that the integration of polio surveillance staff, surveillance activities, and vaccine provision into routine national health systems may destabilize global elimination efforts (
Global Polio Eradication Initiative 2021
). Furthermore, the occurrence of this event during COVID-19, and the documented impact of reallocation of staff to supporting COVID-19 response activities, (Burkholder et al., 2021
) is evidence that surveillance funding should not yet be redirected. The event also highlights the key role and contribution of regional reference laboratories and the need to strengthen these to support molecular surveillance.The second opportunity this event allows for is to use the moment to enlist and strengthen political will and advocate for governments to act in support of polio elimination, in accordance with a key objective of the polio elimination strategy 2022—2026 (
Global Polio Eradication Initiative 2021
). Political commitment is much needed in lower-middle income countries, where significant environmental barriers (outside of program activities such as socio-political instability and economic and infrastructural challenges) to program implementation often lead to discouragement of program implementers and consequential poor program performance (Deressa et al., 2020
). South Africa, for example, lost polio-free certification in 2017 (although it was regained in 2019) (National Institute for Communicable Diseases South Africa 2019
) through failure to achieve surveillance targets following 28 years without polio. The success of the Malawian surveillance program in detecting this isolate may be seen as an encouragement to complacent program officials across the region whose ongoing efforts are required to maintain polio-free certification.Although the isolation of WPV in Malawi is a programmatic blow, it highlights the urgency, determination, and commitment required at all levels to “deliver on the promise” of polio elimination.
References
WHO-AFRO. Malawi declares polio outbreak. 2022. https://www.afro.who.int/news/malawi-declares-polio-outbreak 27 February 2022).
Global Polio Eradication Initiative. GPEI statement on WPV1 in Malawi. 2022. https://polioeradication.org/news-post/gpei-statement-on-wpv1-in-malawi/ 27 February 2022).
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Global Polio Eradication Initiative. Polio this week as of 23 February 2022. 2022. https://polioeradication.org/polio-today/polio-now/this-week/(accessed 27 February 2022.
- Progress Toward Polio Eradication - Worldwide, January 2016-March 2018.MMWR Morb Mortal Wkly Rep. 2018; 67: 524-528
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WHO. AFP/Polio data. 2022. https://extranet.who.int/polis/public/CaseCount.aspx (accessed 27 February 2022.
World Bank. World Integrated Trade Solution - country profile Malawi. 2022. https://wits.worldbank.org/CountryProfile/en/Country/MWI/Year/LTST/Summary 27 February 2022).
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Article Info
Publication History
Published online: March 04, 2022
Accepted:
March 1,
2022
Received:
February 27,
2022
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