RESUMO
For emerging epidemics such as the COVID-19 pandemic, quantifying travel is a key component of developing accurate predictive models of disease spread to inform public health planning. However, in many LMICs, traditional data sets on travel such as commuting surveys as well as non-traditional sources such as mobile phone data are lacking, or, where available, have only rarely been leveraged by the public health community. Evaluating the accuracy of available data to measure transmission-relevant travel may be further hampered by limited reporting of suspected and laboratory confirmed infections. Here, we leverage case data collected as part of a COVID-19 dashboard collated via daily reports from the Malagasy authorities on reported cases of SARS-CoV-2 across the 22 regions of Madagascar. We compare the order of the timing of when cases were reported with predictions from a SARS-CoV-2 metapopulation model of Madagascar informed using various measures of connectivity including a gravity model based on different measures of distance, Internal Migration Flow data, and mobile phone data. Overall, the models based on mobile phone connectivity and the gravity-based on Euclidean distance best predicted the observed spread. The ranks of the regions most remote from the capital were more difficult to predict but interestingly, regions where the mobile phone connectivity model was more accurate differed from those where the gravity model was most accurate. This suggests that there may be additional features of mobility or connectivity that were consistently underestimated using all approaches, but are epidemiologically relevant. This work highlights the importance of data availability and strengthening collaboration among different institutions with access to critical data - models are only as good as the data that they use, so building towards effective data-sharing pipelines is essential.
RESUMO
BACKGROUND: In 1988, the World Health Assembly launched the Global Polio Eradication Initiative. WHO AFRO is close to achieve this goal with the last wild poliovirus detected in 2014 in Borno States in Nigeria. The certification of the WHO African Region requires that all the 47 member states meet the critical indicators for a polio free status. Madagascar started implementing polio eradication activities in 1996 and was declared polio free in June 2018 in Abuja. This study describes the progress achieved towards polio eradication activities in Madagascar from 1977-2017 and highlights the remaining challenges to be addressed. METHODS: Data were collected from the national routine immunization services, Country Acute Flaccid surveillance databases and national reports of SIAS and Mop Up campaign. Country complete polio and immunization related documentation provided detailed historical information's. RESULTS: From 1997 to 2017, Madagascar reported one wild poliovirus (WPV) outbreak and four circulating Vaccine Derived Polio Virus (cVDPV) oubreaks with a total of 21 polioviruses (1 WPV and 21 cVDPV). The last WPV and cVDPV were notified in 1997 in Antananarivo and 2015 in Sakaraha health districts respectively. Madagascar met the main polio surveillance indicators over the last ten years and made significant progress following the last cVDPV2 outbreak in 2014 -2015. In addition, the country successfully implemented the switch from trivalent Oral Polio Vaccine (tOPV) to bivalent Oral Polio vaccine (bOPV) and containment activities. Environmental Surveillance established since 2015 did not reveal any poliovirus. The administrative coverage of the 3rd dose of oral polio vaccine (OPV3) varied across the years from 55% in 1991 to a maximum of 95% in 2007 before a progressive decrease to 86% in 2017. The percentage of AFP cases with more than 3 doses of oral polio vaccines increased from 56% in 2014 to 88% in 2017. A total of 19 supplementary immunization activities (SIA) were conducted in Madagascar from 1997 to 2017, among which 3 were subnational immunization days (sNID) and 16 were national immunization days (NIDs). Poor routine coverage contributed to the occurrence of cVDPC outbreaks in the country; addressing this should remain a key priority for the country to maintain the polio free status.From 2015 to June 2017, Madagascar achieved the required criteria leading to the acceptance of the country's polio-free documentation in June 2018 by ARCC. However, continuous efforts will be needed to maintain a highly sensitive polio surveillance system with emphasis on security compromised areas. Finally strengthening the health system and governance at all levels will be necessary if these achievements are to be sustained. CONCLUSIONS: High national political commitment and support of the Global Polio Eradication Partnership were critical for Madagascar to achieve polio free status. Socio-political instability, weakness of the health system, sub-optimal routine immunization performance, insufficient SIA quality and existing security compromised areas remain critical program challenges to address in order to maintaining the polio free status. Continuous high-level advocacy should be kept in order to ensure that new government authorities maintain polio eradication among the top priorities of the country.
