how we used satellite data to follow the toll of the pandemic
While the impact of the COVID-19 pandemic has been well documented in high-income countries, much less is known about its impact on low-income and conflict-affected countries where there are significant challenges in generation and dissemination of information.
Somalia is one of those countries. He was beaten by a series of humanitarian emergencies, epidemics and population displacements. These crises have been exacerbated, in large part, by three decades of protracted conflict.
But knowing the magnitude of the impact of COVID-19 is next to impossible.
With other colleagues from London School of Hygiene and Tropical Medicine, the Somali Disaster Resilience Institute and Catapult of satellite applications, we conducted a study to understand the impact of the COVID-19 pandemic on Somalia.
The official the figure stood at just over 1,100 deaths in October of this year. But media reports and investigative NGO surveys point To bigger number of potential deaths from COVID-19. This suggests that official data may not capture a full picture of the true burden of COVID-19.
The challenge is to obtain data in a fragile and crisis-affected context.
We overcame this problem by using commercially available high resolution satellite data obtained from Maxar, to count the number of burials in Mogadishu, Banadir region between January 2017 and September 2020. The Banadir region is on the outskirts of the city and is home to approximately 2 million inhabitants.
We compared the number of burials we could count before COVID-19 with those in the pandemic period, between January and September 2020.
We also interviewed key informants to verify what the satellites were showing – in terms of burials – and to understand community perceptions of COVID-19 mortality and the challenges associated with controlling the pandemic.
Based on the number of burials we were able to identify, our analysis revealed a substantial increase in the burial rate during the COVID-19 period.
The application of this rate to the population of Banadir allowed us to draw up a death toll. We repeated this process for the graves identified by satellite imagery in the pre-COVID-19 period, which allowed us to calculate a baseline death toll. The difference between those two numbers – which we called the excess death toll – suggested there had been massive underreporting of deaths.
Using satellite images like this is a new way to identify the number of deaths that may be attributable to the pandemic. It is a promising tool that can be used in resource-limited environments, where field research is a challenge and people remain vulnerable to renewed waves and new variants.
For satellite data, we worked on the hypothesis that all the deceased from Banadir are buried in recognized cemeteries. We then sought to identify and collect data on each âactiveâ cemetery (receiving new burials) at any time during the analysis period.
A total of 68 sequential satellite images were available in the six cemeteries analyzed, an average of 11 images per cemetery. We were able to perform an exhaustive count of the graves for 58.8% (40/68) of the images. This was mainly because some of the images weren’t clear enough to identify the graves, or because the view was obstructed by vegetation. We had to rely on satellite data collected retrospectively by Maxar, thus limiting the number of usable data points.
For eight images (11.7%), we analyzed only the visible area and created a model to predict the missing tomb sightings.
During the pre-COVID-19 baseline period (between 2017 and 2019), daily burials at the six cemeteries averaged between 10 and 12. As of January 2020, an increase in burials – peaking at over 20 per day in June 2020 – was obvious.
Official figures in October 2020 stood at 3,864 cases and 99 deaths across Somalia. On the other hand, from January to September 2020, we estimated an excessive number of deaths between 3,200 and 11,800 in the Banadir region alone. This suggests that the nationwide death toll could be considerably higher.
We used key informant interviews to gain insight into what was behind the high death toll in Somalia. We interviewed a variety of people, including health officials, gravediggers and religious leaders.
At the start of the pandemic in March 2020, the government imposed lockdown and restrictions on public travel and meetings. This included closing schools, government offices and restricting international travel.
But people we spoke to told us there was a lot of skepticism about the existence of COVID-19. This meant that in reality compliance was low, therefore community interactions and public gatherings continued to function normally. Hotels, teahouses, mosques and other public places remained open.
Our informants painted a portrait of a health system ill-prepared to face the scale of the epidemic. Several of our key informants mentioned a shortage of key equipment and treatment facilities. People we spoke to also mentioned the high prices of face masks and antiseptics that put them out of the reach of ordinary people.
While most of these deaths are likely due to COVID-19, we have also heard that some were due to indirect effects of the pandemic, such as socio-economic disruption or reduced access to health services.
Know the toll
Our study suggests a significantly higher number of deaths from COVID-19. It also sheds light on some of the factors behind this high death toll.
We believe our methods – using satellites and geospatial analysis – may be essential in monitoring COVID-19-related death rates in other countries, such as South Sudan and Ethiopia, where reporting is difficult. due to access difficulties or conflict.
The death toll is one of the clearest indicators of the impact of pandemics and can be used by policy makers to make more effective decisions.