Hidden Costs of Chikungunya Virus Unveiled

The emerging threat of mosquito-borne chikungunya viral infection has most likely been significantly underestimated, with total costs estimated to be around $50 billion in 2011-20 alone, according to a comprehensive data analysis published in the open access journal BMJ Global Health.

In the short term, symptoms may include fever, severe joint discomfort, rash, and exhaustion. While these symptoms usually go away, those who are impacted may experience long-term, devastating side effects such as persistent arthritic-type joint pain, exhaustion, and depression, according to the study.

The first chikungunya outbreak was documented in 1952 in Tanzania. However, over the last two decades, the virus has become a serious public health concern due to the increased geographical spread of its vectors, Aedes aegypti and Aedes albopticus mosquitoes, according to the researchers.

“This spread, driven by factors such as globalization, urbanization, and environmental changes, significantly heightens the threat of explosive, unpredictable outbreaks in both the developed and developing world,” they emphasize.

They also emphasize that the true prevalence of chikungunya is likely underreported due to misdiagnosis, insufficient diagnostic infrastructure, and challenges with healthcare access, among other factors.

To better inform preventive and infection control strategies, the researchers synthesised data from multiple sources and used advanced modelling techniques to provide a comprehensive overview of chikungunya’s toll between 2011 and 2020.

These sources included the Programme for Monitoring Emerging Diseases (ProMED), local health ministries, the Pan American Health Organization (PAHO), the European Centres for Disease Control and Prevention (ECDC), the US Centers for Disease Control and Prevention (CDC), and the WHO CHOICE initiative.

Direct costs included medical care (diagnostics, hospital stays, outpatient care, and medicines). The term “indirect costs” related to patient and caregiver workplace absenteeism.

Between 2011 and 2020, 110 nations and regions reported an estimated 18.7 million cases of chikungunya, after accounting for underreporting. An estimated 7.9 million people (range 1.3-16.8 million) had chronic illness.

The majority of cases were reported in Latin America and the Caribbean, where around 15 million people were affected.

The countries with the most cases were Brazil (3.2 million), the Dominican Republic (2.7 million), and French Polynesia (1.6 million). Central and Eastern Europe and Central Asia had the fewest occurrences, with 202 scattered across six countries and primarily caused by travelers returning from endemic areas.

Globally, an estimated 13,000 persons died as a result of their infection in its acute phase (2,242 to 336,286).

Cases peaked at 8.7 million in 2014, when outbreaks were reported in the Dominican Republic, Guadeloupe, French Polynesia, French Guiana, and a number of Caribbean islands.

Estimates of the overall number of DALYS (disability adjusted life years)–years of life lost due to a disability/illness/death–totaled 1.95 million, comparable to an average annual loss of 195,000.

Chronic disease accounted for the majority of the total, 1.5 million (76%) DALYs, with acute sickness accounting for the remaining 476,000 (24%).

The biggest number of DALYs occurred between 2014 and 2016, with 913,000, 432,000, and 262,000, respectively, suggesting severe chikungunya outbreaks. DALYs also peaked in 2019, at 131,000.

Latin America and the Caribbean accounted for 80% of total DALYs (1.6 million), followed by Southeast Asia, East Asia, and Oceania at 12% (237,000).

Between 2011 and 2020, Brazil led the world in DALYs, with 329,000, accounting for 17% of the total.

The researchers estimated that the financial cost of chikungunya during this time period was US$ 49.9 billion, with US$ 25.1 billion for chronic sickness and US$ 24.8 billion for acute illness.

Total direct expenditures were $2.8 billion (6% of the total), with total indirect costs of $47.1 billion (94%). Absenteeism was the primary driver of both types of costs. The global average cost of each instance was $2700.

Once again, Latin America and the Caribbean suffered the brunt of the costs.

The researchers recognize that data quality and availability differed among nations, and the modelling was based on certain assumptions and simplifications due to data constraints, all of which may have altered the precision of the estimations.

Furthermore, the estimates are simply a snapshot of the health and economic toll caused by chikungunya within a certain time period and may not have correctly recorded changes over time, they say.

But they nevertheless state: “Our study reveals a substantial economic and health burden of chikungunya worldwide, especially in Latin America and the Caribbean.

“[These] regions had the highest DALY and cost burden, mainly due to the high case numbers in Brazil, the Dominican Republic, and Colombia, reflecting the rapid expansion in a naïve population since [the] introduction [of the chikungunya virus] in 2013.”

And they conclude: “The health and economic burden of chikungunya is substantial, and might be underestimated up until now. Especially considering its potential to cause explosive outbreaks and considerable long-term health consequences, it is crucial to have a thorough understanding of this disease.”

For more information: BMJ