PIN6 Japanese Encephalitis in Asia: Clinical Burden and Cost-Effectiveness of Vaccination Program

Abstract

To report clinical burden of Japanese encephalitis (JE) in Asia and cost-effectiveness of JE vaccination program. Systematic literature searches were conducted using Embase®, MEDLINE®, WHO, and Google scholar platforms to identify relevant studies in patients with JE. Eligibility of trials was assessed by two reviewers with any discrepancy reconciled by a third, independent reviewer. A total of 10 studies out of 41 retrieved, met the inclusion criteria for the clinical review. Approximately 35,000-50,000 JE cases and 10,000–15,000 deaths due to JE were reported every year in Asia. Incidence of JE was high in China and India, with China accounting for 50% of the JE cases reported worldwide. The incidence of JE in China was reported to be 0.01-1.53 residents/year/100,000. The number of JE cases reported in China, India, Nepal, Sri Lanka, and Bangladesh were 5,000-10,000, 1,500-4,000, 1,000-3,000, 100-200, and 56, respectively. JE caused 12,038 and 2,496 deaths in Southeast Asia and Western Pacific, respectively (2008). JE was associated with 491,797 disability-adjusted life years (DALYs) in the Southeast Asia and 185,573 DALYs in the Western Pacific region (2004). Four studies out of 59 retrieved, met the eligibility criteria for evaluating cost-effectiveness of JE vaccination. JE vaccination prevented 117 cases and 12 deaths (Vietnam), 103 cases and 18 deaths (Thailand), 420 cases and 105 deaths (China), and 175-316 cases and 36-65 deaths (India). Total savings in the direct medical costs witnessed as a consequence of JE vaccination were $51,122 (Vietnam), $58,776 (Thailand), $614,762 (China), and $178,558-$319,627 (India). JE has lead to significant morbidity in survivors and mortality in Asian countries. Existing evidence from cost-effectiveness studies demonstrated that vaccination program markedly reduced the burden of JE in Asia.