MAIRE CONNOLLY: Emerging and reemerging diseases, such as SARS, pandemic H1N1, MERS, Ebola, yellow fever, Zika, cholera, and drug-resistant infections, have caused significant morbidity and mortality among populations in low-and middle-income countries. As we saw in the earlier step on “History of disease outbreaks and their impact”, outbreaks have affected human populations throughout history. Bubonic plague, also known as the Black Death, spread from Asia along the Silk Road, killing between 30% and 60% of Europe’s population between 1347 and 1350. An estimated 75 to 200 million people died in this outbreak.
Smallpox caused approximately 15 million cases a year in 1967, with a mortality rate of 30% before WHO commenced a global vaccination campaign in 1966 and certified the disease as eradicated globally in 1980. Over 500 million people were infected worldwide in 1918 by influenza, the so-called Spanish flu, or about one third of the planet’s population. And an estimated 50 million people died.
It has been estimated that if an influenza pandemic similar in severity to the 1918 pandemic were to hit today, there could be 62 million deaths, of which 96% would be in low- and middle-income countries. Regardless of where an outbreak starts, low-and middle-income countries tend to bear the brunt due to weaker health systems and limited capacity to handle surges in cases. The most recent influenza pandemic, H1N1, also known as swine flu, was first detected in Mexico in April 2009. Researchers estimated that the global infection rate was 11% to 21%, which is lower than what was previously expected. WHO estimated almost 285,000 people died from H1N1, with the majority of these deaths occurring in Africa and Southeast Asia.
The social and economic impact of disease outbreaks are often much greater than would be expected from the number of cases of disease and deaths. The impact of an outbreak depends on both the direct health consequences and indirect effect of disease control measures. These include social distancing interventions, such as school and workplace closures, quarantine, and restrictions on trade and travel. Fear-based behaviour due to lack of information or reduced trust in governments and institutions also play a role. In low- and middle-income countries, acute economic disruption carries particular risks for poor households, as they may have less access to health care and lower savings to protect against financial catastrophe.
Outbreaks can adversely impact on an economy’s long-term growth by the destruction of human capital. Human capital, the stock of knowledge embodied in the population, is considered an important determinant of long-term growth. Furthermore, the decline in health capital as measured in general by life expectancy has negative effects on economic growth. For example, Liberia lost 8% and Sierra Leone 7% of their health care workers to Ebola, with longer-term indirect impacts on already fragile health systems far beyond the duration of the epidemic. In terms of the economic impact of the West African Ebola outbreak, in 2016, the World Bank estimated a loss of $2.8 billion in gross domestic product.
This was due to lower investment and a substantial loss in private sector growth and agricultural production, leading to concerns about food security and cross-border trade, as restrictions on movement, goods, and services increased.
A more recent study estimated the comprehensive economic and social burden of the Ebola outbreak was much higher at $53 billion, with the most significant component being deaths from non-Ebola causes. The cost of deaths due to TB, HIV, and malaria was estimated at about 18 billion Euro. The social and economic costs of other outbreaks have been estimated. The MERS outbreak in South Korea in 2015, despite causing only 186 cases with a death toll of 36, reduced domestic spending significantly and led to a 40% fall in tourist numbers within one month of the outbreak’s onset. The country’s economic growth dropped from 0.8% in the preceding quarter to 0.3% following the onset of MERS, marking a six-year record low.
The cost of an outbreak to health care systems of medical treatment of cases and outbreak control can be substantial. An outbreak can overwhelm the health system, limiting capacity to deliver routine health care, particularly in low-resource settings. Vulnerable populations, especially the poor, are likely to suffer disproportionately. The Ebola outbreak in West Africa severely impacted the provision of health care services. It has been estimated that an additional 10,600 lives were lost to TB, HIV, and malaria during the outbreak due to resources being tied up in the Ebola response and reduced admission rates in hospitals. This is nearly equivalent to the number of people who died from Ebola and was a significant economic burden to the overall cost of the outbreak.
In addition, there are national and international security implications of outbreaks through the societal breakdown and loss of social cohesion that they may generate. The widespread looting in West Africa during the Ebola outbreak in 2014 had major social and economic repercussions. The OECD has identified infectious disease outbreaks and pandemics as a potential future global shock, along with financial crises and cyber risks. The cost of ensuring adequate pandemic preparedness worldwide is estimated at about $3.4 billion a year. Recent work by the World Bank estimated that the annual global cost of a moderate to severe pandemic could run as high as $570 billion, or 0.7% of global income. In the course, these issues are explored more closely in upcoming steps.
Outbreak preparedness will be dealt with in more detail in week two of the course. And later this week, there is the opportunity to discuss and debate why we should invest resources in outbreak preparedness and response. It is clear that the wider costs of an outbreak are significantly greater than the numbers of cases and deaths. The social and economic consequences can continue for years after an outbreak has been controlled. For this reason, ensuring effective outbreak preparedness at national, regional, and global levels is crucial to protect human populations against future epidemic threats.