Monitoring the evolution of vaccine-derived poliovirus in East and Southern African countries, 2010 - 2021.

Introduction: the Africa region was certified indigenous wild poliovirus-free in August 2020. Countries in East and Southern Africa have, during acute flaccid paralysis (AFP) and environmental surveillance (ES), detected equally concerning vaccine-derived polioviruses (VDPVs) that have not been systematically documented to guide programming in the sub-region. The study documents trends and salient observations of the VDPVs by country of detection, for 11 years from 2010 to 2021. Methods: we conducted secondary data analysis, a descriptive study design, by deploying field and laboratory of AFP and environmental surveillance databases of the 20 East and Southern African countries from 2010 to 2021. Results: a total of 318 VDPVs were reported over the study period. The majority were from AFP cases (58.8%) and the rest equally distributed between healthy community children and environmental surveillance sources. More polioviruses were detected after 2016 than during the period before. We observed that more boys were affected by VDPVs compared to girls. Children under 5 years were more affected than other age groups, with a mean age of 3.6 years. Delay of samples in the field seemed to increase the likelihood of not reporting VDPVs and not mounting timely public health detailed investigations and vaccination responses. Conclusion: the study provides useful evolutional trends of VDPVs for surveillance and vaccination programming. We also noted that the VDPV2s have been increasing after the 2016 tOPV to oral polio vaccine (bOPV) switch. The COVID-19 pandemic emergence in 2020, led to a decline in AFP, ES surveillance, and immunization activities. Our findings point to the need to implement enhanced tailored childhood immunization recovery strategies and to speed up the use of inactivated polio vaccine (IPV) to boost population immunity.

Early effects of the COVID-19 pandemic on the acute flaccid paralysis surveillance in East and Southern African countries.

INTRODUCTION: the World health organisation (WHO) African Region reported the first confirmed COVID-19 case caused by the SARS-CoV-2 on 25th February 2020, and the first case for the East Southern Africa (ESA) sub-region was on 5th March 2020. Almost all countries in the ESA sub region implemented the WHO-recommended preventive measures variably after the notification of community transmission of the COVID-19 disease. This resulted in the disruption of the outpatient, immunization surveillance, and the related supply chain activities. METHODS: a comparative analysis study design of secondary acute flaccid paralysis (AFP) surveillance data received from the East and Southern Africa sub-region countries to evaluate the effect of the COVID-19 pandemic in the AFP field surveillance for the same time period of March to December 2019 and 2020. RESULTS: we observed that 52.4% of second stool samples were received in the laboratory within 72 hours from March to December 2019, and only 48.1% in the same period of 2020. A 4.3% decline with a p-value of <0.0001 (95% CI, ranges from 2.326% to 6.269%). Similarly, we noted a 4.7% decline in the number of reported AFP cases in the ESA sub-region for March to December 2020 compared to the same period in 2019, a p-value of less than 0.001 (95% CI ranges from 2.785 to 6.614). For the percentage of stool adequacy, we observed a 3.37% decline for April in 2020 compared to April 2019 with a p-value of less than 0.001 (95% CI ranges from 2.059 to 4.690). CONCLUSION: we observed a decline in the core AFP surveillance (non polio) NP-AFP rate, and percentage of stool adequacy in countries severely affected by the COVID-19 disease. These countries implemented stringent transmission prevention measures such as lock-down and international transportation restrictions.

The experiences of using polio outbreak simulation exercises to strengthen national outbreaks preparedness and response plans in sub-Saharan Africa.

INTRODUCTION: globally, by 2020 the paralytic poliomyelitis disease burden decreased to over 99% of the reported cases in 1988 when resolution 41.8 was endorsed by the World Health Assembly (WHA) for global polio eradication. It is clearly understood that, if there is Wild Poliovirus (WPV) and circulating Vaccines Derived Poliovirus (cVDPV) in the world, no country is safe from polio outbreaks. All countries remain at high risk of re-importation depending on the level of the containment of the types vaccine withdrawn, the laboratory poliovirus isolates, and the population immunity induced by the vaccination program. In this regard, countries to have polio outbreak preparedness and response plans, and conducting the polio outbreak simulation exercises for these plans remain important. METHODS: we conducted a cross-section qualitative study to review to 8 countries conducted polio outbreak simulation exercises in the East and Southern Africa from 2016 to 2018. The findings were categorized into 5 outbreak response thematic areas analyzed qualitatively and summarized them on their strengths and weaknesses. RESULTS: we found out that, most countries have the overall technical capacities and expertise to deal with outbreaks to a certain extent. Nevertheless, we noted that the national polio outbreak preparedness and response plans were not comprehensive enough to provide proper guidance in responding to outbreaks. The guidelines were inadequately aligned with the WHO POSOPs, and IHR 2005. Additionally, most participants who participated in the simulation exercises were less familiar with their preparedness and response plans, the WHO POSOPs, and therefore reported to be sensitized. CONCLUSION: we also realized that, in all countries where the polio simulation exercise conducted, their national polio outbreak preparedness and response plan was revised to be improved in line with the WHO POSOPs and IHR 2005. we, therefore, recommend the polio outbreak simulation exercises to be done in every country with an interval of 3-5 years.

Assessment of acute flaccid paralysis surveillance performance in East and Southern African countries 2012 - 2019.

INTRODUCTION: polio eradication initiatives started in 1988, this is almost the past 32 years following the WHA resolution 41.8 of eradicating polio by the year 2000. As of 2019, only 3 countries remained to be polio endemic globally, Afghanistan, Pakistan and Nigeria. The east and southern sub-region countries had shown progressive achievement towards polio eradication and to start with the African regional certification. The availability of sensitive AFP surveillance performance is among important strategies in the achievement of polio eradication. We, therefore, decided to conduct this assessment of AFP performance from 2012 to 2019 in the ESA sub-region have evidence documentation and support the certification process of the WHO AFRO region. METHODS: we reviewed all reported acute flaccid paralysis (AFP) cases from 19 countries in the ESA sub region with the date of onset of paralysis from 1 January 2012 to 31 December 2019. The data were run to descriptive analysis based on the personal characteristics and AFP surveillance performance indicators parameters. RESULTS: a total of 46,014 AFP cases were reported from 19 countries in the ESA countries who were paralyzed from 1 January 2012 to 31 December 2019. The most affected age group was children aged 0 to 3 years old where 19,740 children with acute paralysis were reported representing 42.9% of the total reported AFP for the period. The overall assessment of the non-polio AFP rate, there is an increase from a rate of 2.7 in 2012 to 3.5 in 2019 per 100,000 population aged less than 15 years, reflects a significant change with a p-value of 0.040 (95% C.I. ranges from 0.035 to 1.564). Furthermore, the percentage of stool adequacy raised from 86.4% in 2012 to 88.5% in 2019, with an observed 2.1% difference and no significant change over the 8 years. CONCLUSION: we observed an overall increase in the sensitivity of the AFP surveillance performance for the ESA sub-region countries from 2012 to 2019 using the national performance indicators. The COVID-19 pandemic paused an operational challenge for AFP surveillance performances from 2020. A further subnational surveillance performance analysis is suggested.