Wednesday, March 30, 2016

Declining Trend of Hepatitis A Seroepidemiology in Association with Improved Public Health and Economic Status of Thailand

Hepatitis A virus (HAV) is transmitted via the fecal-oral route from contaminated food or water. As part of the most recent survey of viral hepatitis burden in Thailand, we analyzed the current seroprevalence of HAV in the country and compared with data dating back to 1971. From March to October, 2014, a total of 4,260 individuals between one month and 71 years of age from different geographical regions (North = 961; Central = 1,125; Northeast = 1,109; South = 1,065) were screened for anti-HAV IgG antibody using an automated chemiluminescent microparticle immunoassay. Overall, 34.53% (1,471/4,260) possessed anti-HAV IgG antibody, and the age-standardized seroprevalence was 48.6%. Seroprevalence rates were 27.3% (North), 30.8% (Central), 33.8% (Northeast) and 45.8% (South) and were markedly lower than in the past studies especially among younger age groups. The overall trend showed an increase in the age by which 50% of the population were anti-HAV IgG antibody: 4.48 years (1971–1972), 6 (1976), 12.49 (1990), 36.02 (2004) and 42.03 (2014).This suggests that Thailand is transitioning from low to very low HAV endemicity. Lower prevalence of HAV correlated with improved healthcare system as measured by decreased infant mortality rate and improved national economy based on increased GDP per capita. The aging HAV immuno-na├»ve population may be rendered susceptible to potential HAV outbreaks similar to those in industrialized countries and may benefit from targeted vaccination of high-risk groups.

Below:  Map of Thailand and the domicile of study participants

Below:  Correlation between infant mortality rate (per 1,000 live births), GDP, and age at which 50% of the population possessed anti-HAV antibody

Below:  Documented hepatitis A outbreaks in Thailand from 1984 to 2014

Full article at:

1Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Pathum Wan, Bangkok, Thailand
2Chumphae Hospital, Chum Phae, Khon Kaen, Thailand
3Uttaradit Hospital, Mueang Uttaradit, Uttaradit, Thailand
4Laplae Hospital, Laplae, Uttaradit, Thailand
5Naresuan University Hospital, Mueang Phitsanulok, Phitsanulok, Thailand
6Phra Nakhon Si Ayutthaya Hospital, Phra Nakhon Si Ayutthaya, Thailand
7King Narai Hospital, Mueang Lop Buri, Lop Buri, Thailand
8Narathiwat Ratchanakarin Hospital, Mueang Narathiwat, Narathiwat, Thailand
9Trang Hospital, Mueang Trang, Trang, Thailand
10Bureau of Epidemiology, Department of Disease Control, Ministry of Public Health, Mueang Nonthaburi, Nonthaburi, Thailand
Kaohsiung Chang Gung Memorial Hospital, TAIWAN

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