Date Published: April 5, 2017
Publisher: Public Library of Science
Author(s): Eunha Shim, Daniela Flavia Hozbor.
The incidence of dengue fever (DF) is steadily increasing in Mexico, burdening health systems with consequent morbidities and mortalities. On December 9th, 2015, Mexico became the first country for which the dengue vaccine was approved for use. In anticipation of a vaccine rollout, analysis of the cost-effectiveness of the dengue vaccination program that quantifies the dynamics of disease transmission is essential.
We developed a dynamic transmission model of dengue in Yucatán, Mexico and its proposed vaccination program to incorporate herd immunity into our analysis of cost-effectiveness analysis. Our model also incorporates important characteristics of dengue epidemiology, such as clinical cross-immunity and susceptibility enhancement upon secondary infection. Using our model, we evaluated the cost-effectiveness and economic impact of an imperfect dengue vaccine in Yucatán, Mexico.
Our study indicates that a dengue vaccination program would prevent 90% of cases of symptomatic DF incidence as well as 90% of dengue hemorrhagic fever (DHF) incidence and dengue-related deaths annually. We conclude that a dengue vaccine program in Yucatán, Mexico would be very cost-effective as long as the vaccination cost per individual is less than $140 and $214 from health care and societal perspectives, respectively. Furthermore, at an exemplary vaccination cost of $250 USD per individual on average, dengue vaccination is likely to be cost-effective 43% and 88% of the time from health care and societal perspectives, respectively.
Dengue fever (DF) is a febrile illness that is caused by any one of four serotypes of flavivirus (DENV-1, DENV-2, DENV-3, and DENV-4) that cross-react immunologically. Dengue is endemic in more than 100 countries, causing more than 390 million infections annually, 96 million of which are clinical dengue infections [1–4]. Infection with dengue virus provides serotype-specific, long-term protection as well as temporary cross-protection against the other serotypes for 6–24 months [3, 5]. However, people who have had a single primary infection have a higher risk of developing dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) upon a second infection, a phenomenon attributed to antibody-dependent enhancement (ADE) [3, 6]. Thus, more dengue diseases occur primarily in patients who reside in hyperendemic areas in which multiple serotypes circulate simultaneously. Although mild dengue disease and DF contribute to more than half of the total public health burden of dengue-associated illnesses , the more serious manifestations of DHF and DSS are the major impetuses behind emerging efforts to prevent infection .
We calculated the equilibria for the annual dengue infection incidence in the absence of vaccination (1,060 per 100,000) and the annual symptomatic dengue fever incidence (539 per 100,000), which were comparable to empirical estimates [36, 37, 47–49]. The annual DHF incidence in Yucatán, Mexico was estimated to be 12 per 100,000 [48, 49]. Accordingly, we estimated the total cost of dengue per year in Yucatán, Mexico to be $1.86 million for the health care system and $3.41 million for society.
Dengue is a major public health issue in tropical and subtropical countries in Latin America and Asia. On December 9th, 2015, Mexico became the first country to approve a vaccine against dengue, Dengvaxia®. Dengvaxia® is the first vaccine to be licensed in the world for the prevention of dengue, and it was approved in Mexico for the prevention of dengue disease in individuals aged 9–45 years old living in endemic areas . The approval of the dengue vaccine will be a critical addition to the ongoing public education and vector control efforts in Mexico, and it will help to achieve the WHO’s goal to reduce dengue mortality and morbidity by 50% and 25%, respectively, by 2020 in endemic countries .