Cellphone coverage aided virus containment in Liberia during Ebola outbreak, study finds

cell towers

New research from Elisa Maffioli

Assistant Professor of Health Management and Policy and Global Public Health

April 30, 2024

University of Michigan and Georgia Institute of Technology researchers have discovered that cellphone coverage was associated with a significant reduction in Ebola cases during the 2014 outbreak in Liberia. The study, which utilized novel data on signal strength from cellphone towers and Ebola case reports and was published in the Journal of Development Economics, indicates that villages with adequate cellphone coverage experienced an average drop in Ebola occurrence of 10.8 percentage points. This reduction is attributed primarily to the enhanced ability to seek treatment, as revealed by a post-epidemic survey, rather than an increase in access to preventative information.

In this Q&A, Elisa Maffioli, assistant professor of Health Management and Policy and Global Public Health at the University of Michigan School of Public Health, and Robert Gonzalez, assistant professor of Economics at the Georgia Institute of Technology School of Economics, detail their study and findings.

What drew you to pursue this work?

Before COVID-19, we feel that most people weren’t thinking about health epidemics as being one of the major worldwide threats. While Ebola received some attention in developed countries like the US, very few people were directly affected in this population and West-African countries bore the brunt of the outbreak.

One thing that came to mind was to inform and better prepare people for future epidemics. How could that be done in a lower-income country such as Liberia? Well, phones are everywhere! 

We started discussing the relationship between cellphones and health epidemics and brainstormed about interesting things we could learn in the context of Liberia, given previous work Elisa conducted. Ultimately we landed on the question of whether cellphone technology helped—or did not help— contain the 2014 Ebola epidemic. We were interested in learning what we could do to inform policymakers for the next one. 

What were the key findings of your study? Was there anything that surprised you?

This study is a result of a great effort to combine several data sources, which is quite unique. 

  1. We used data on Ebola cases compiled from primary records obtained from Liberia’s Ministry of Health (MOH), which includes all villages in the country for the duration of the epidemic.
  2. We gathered data on the location and characteristics of cellphone towers across Liberia prior to the outbreak—obtained from the Liberia Telecommunications Authority (LTA).
  3. Elisa conducted an original survey six months after the end of the epidemic with roughly 2,000 respondents across Liberia.
  4. We used more than 233 million anonymized call detail records (CDR) obtained from one of the major mobile network operators in the country. 

The key finding of the study was that having access to cellphone coverage, as a proxy for cellphone access, reduced the likelihood of getting Ebola, which in practice helped contain the epidemic. In addition, using novel survey data collected after the epidemic, we assessed the importance of several channels that may explain the relationship between cellphone coverage and epidemic containment. 

We found evidence that this reduction in the likelihood of getting Ebola is likely explained by facilitating access to treatment, such as the timely arrival of ambulances and closer community health care centers. Initially we thought that the cellphone access could have also increased access to information and prevention, but we did not find strong evidence of this. 

After being surprised at first, we now think that this finding is plausible since, in the short run, the returns of timely ambulance service or care centers are likely higher and immediately realized. Instead, the effects of prevention may take longer to materialize as they essentially entail a change in health behavior.

Can you expand on this portion of your paper: “...our paper explores whether the technology is effective in the midst of a health crisis–a sudden-onset epidemic–in a setting characterized by general mistrust towards local and international institutions. Our paper shows that cellphones can be effective even in such settings.”

As mentioned, there are two interesting features here. One, we tested how having access to pre-existing mobile phones changed the likelihood of being affected by Ebola. Thus, the results are generalizable to similar situations. Our results on the mechanisms (treatment matters more than prevention) might be explained by the fact that the impact of treatment is larger and immediately observed during a health crisis, but this might not be true for cellphone usage in normal times or to do epidemic preparedness.

Two, Liberia is an interesting setting to explore given its history. Like many other African countries, Liberia is still characterized by poor health infrastructure and mistrust in state institutions, making it one of the most vulnerable countries in the world to infectious diseases. From 1989 to 2003, the country experienced two civil wars, shattering the strained relationship between Liberian citizens and their government. Liberia was then affected by an Ebola outbreak between March 2014 and May 2015, and it also experienced COVID-19 starting in March 2020. Finding these results in this setting is quite important, because it shows the great potential of using cellphones in other low-income countries. It shows how something we view as simple and ubiquitous as a cellphone can have positive externalities on health outcomes and help contain an epidemic. 

What should people take away from this paper and its findings? Are there policy considerations that you want to highlight? 

Despite our results speaking to what happened in the middle of an epidemic, we think there are important policy takeaways from this work that apply to normal times. 

It is clear that we cannot expect policymakers to invest in cellphone towers in times of emergency. Yet, in normal times, longer term policies that invest in the expansion of cellphone coverage to remote areas and information campaigns to prompt changes in preventive health behavior can be fruitful. 

In times of epidemics, policymakers should take advantage of increased cellphone coverage to implement shorter-run, emergency policies (e.g., hotlines) and measures that enhance access to treatment care.

Media Contact

Destiny Cook

Senior Public Relations Specialist
University of Michigan School of Public Health
734-647-8650

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