Risk of polio spreading in Zim, neighbouring countries remains high

Zimbabwe last reported a case of indigenous wild poliovirus (WPV) in 1986 and has been certified polio free since 2005.

IN October 2023, Zimbabwe declared polio outbreak as a public health emergency following the detection of circulating vaccine derived poliovirus type 2.

Highlights

  • An index human polio virus type 2 was reported in a 10-year-old girl with a case of acute flaccid paralysis (AFP) in January 2024.
  • During the reporting period, April 27 to May 10, no new vaccine derived poliovirus type 2 case has been reported from environmental sites in Harare while one new cVDP2 case was reported in the previous reporting period from March 13 to April 26 2024.
  • To date, Zimbabwe has detected 22 circulating vaccine derived poliovirus type 2 cases from four environmental samples in Harare since October 2023 (17 cases from 2023 and five in 2024).
  • Between April 29 and May 3 (week 17), 10 new AFP cases were reported (cumulative 107 cases) with a non-polio acute flaccid paralysis rate at 3,8% for children over 15 years.
  • Zimbabwe has intensified its polio/vaccine preventable disease  surveillance efforts through expansion of environmental samples sites in four additional provinces and trainings for the provincial surveillance officials in two districts has been completed.

Situation overview and humanitarian needs

Zimbabwe last reported a case of indigenous wild poliovirus (WPV) in 1986 and has been certified polio free since 2005.

Following the detection of wild poliovirus 1 in Mozambique and Malawi, in 2022, Zimbabwe undertook multi-country supplementary immunisation activities (SIAs) with bivalent oral polio vaccine and conducted four rounds of SIA in 2022 and 2023.

The circulating vaccine derived poliovirus type 2 outbreak was declared a public health emergency by the Health and Child Care minister in October 2023.

Polio outbreak response activities commenced with plans to conduct two rounds of SIAs using novel oral poliomyelitis (polio) vaccine type 2 in February and March 2024 reaching 4,6 million and 4,8 million children under 10 years of age respectively in each round.

The proportion of districts that passed lot quality assuring sampling results increased from 73% in round one to 82% in round two of monovalent oral polio vaccine campaign.

During the reporting period, no new environmental samples confirmed positive vaccine derived poliovirus type 2 from environmental sites in Harare, bringing cumulative positive vaccine derived poliovirus type 2 cases to 22 (17 from 2023 and five in 2024) from four environmental sites in Harare since October 2023.

Furthermore, 10 new AFP cases were reported between April 20 to May 3, 2024 (week 17) (cumulative 107 cases since 2024) with a non-polio acute flaccid paralysis rate at 3,8% for children over 15 years.

The risk of poliovirus spreading within the country and neighbouring countries remains high due to continuous circulation of vaccine derived poliovirus type 2 to countries that already have ongoing outbreaks.

In addition, most countries in the southern Africa subregion face challenges in terms of population immunity.

Therefore, it is crucial to strengthen routine immunisation through various strategies, such as implementing big catch-ups and immunisation recovery programs, to mitigate the risk.

Special considerations to target specific population groups with customised social behaviour change strategies are made in the polio outbreak response.

These specific population groups include vaccine hesitant religious groups with high concentration in Manicaland province (Buhera, Mutasa and Mutare districts), populations in refugee camps (Tongogara in Manicaland province and Waterfalls transit camp in Harare), populations along borders, cross border traders, artisanal miners, and populations in emerging peri-urban settlements in Harare.

The Health and Child Care ministry has planned a review meeting with the National Immunisation Technical Advisory Group for technical advice for an additional SIAs focusing on high-risk population groups in Harare province using the available balance of monovalent oral polio vaccine from the previous campaigns.

A national expanded programme on immunisation strengthening plan has been developed and shared with partners for the resource mobilisation to improve routine immunisation. - Unicef

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