Risk Factors for Acute Hepatitis A Infection in Korea in 2007 and 2009: A Case-Control Study

Abstract

This study aimed to identify the risk factors associated with acute hepatitis A virus (HAV) infection in the Korean population. Participants were recruited from five referral hospitals across the country in 2007 and from 11 hospitals in 2009. Patients with positive anti-HAV IgM antibody tests became the case group, while patients treated for non-contagious diseases at the same hospitals were recruited as controls. A total of 222 and 548 case-control pairs were studied in the 2007 and 2009 surveys, respectively. Data from the surveys were analyzed jointly. In a multivariate analysis, sharing the household with HAV-infected family members (OR, 6.32; 95% CI, 1.4-29.6), contact with other HAV-infected individuals (OR, 4.73; 95% CI, 2.4-9.4), overseas travel in 2007 (OR, 19.93; 95% CI, 2.3-174.4), consumption of raw shellfish (OR, 2.51; 95% CI, 1.8-3.5), drinking bottled water (OR, 1.64; 95% CI, 1.3-8.4), and occupation that involve handling food (OR, 3.30; 95% CI, 1.3-8.4) increased the risk of HAV infection. Avoiding contact with HAV-infected individuals and avoiding raw foods eating could help minimize the risk of hepatitis A infection. Immunization must be beneficial to individuals who handle food ingredients occupationally or travel overseas to HAV-endemic areas.

Age-period-cohort analysis of hepatitis A incidence rates in Korea from 2002 to 2012

“…This result is consistent with the reported age-specific seroprevalence rate in Korea [11,12], as the high seroprevalence in individuals <10 years of age is related to vaccination that was introduced in 1997 [4], and the high seroprevalence in individuals >40 years of age is related to childhood infections that occurred before Korea’s rapid socioeconomic development and public sanitation improvements [11-13]. Therefore, hepatitis A occurred most frequently in the 20-39-year-old group, who exhibited a low seroprevalence rate.…”

“…This economic development and concomitant improvements in public sanitation have altered the epidemiology of hepatitis A in Korea, and the endemicity of hepatitis A has changed from high to intermediate [10]. In this context, various studies have evaluated the incidence, seroprevalence, risk factors, and vaccination status for hepatitis A [3,4,11-15], and have reported high incidence rates among individuals who are 20-39 years old. Nevertheless, it is likely that recent changes in age cohorts, vaccination status, lifestyle, and overseas travel have influenced the incidence of hepatitis A.…”

“…Lifelong immunity is often acquired after HAV infection [3], and hepatitis A during childhood is generally asymptomatic or causes flu-like symptoms. However, it is also associated with symptoms that range from nausea and vomiting to fulminant hepatitis and death among adults [1,2,4,5]. Unfortunately, hepatitis A is one of the most common infectious diseases in the world [6], and its incidence varies according to socioeconomic development and public sanitation.…”

Monitoring the Hepatitis A Virus in Oyster from Korea

“…Previous studies have shown that eating raw shellfish was shown to be a significant predictor of HAV infection in the multivariate analysis [21] and eating raw shellfish significantly increased the odds ratio of HAV infection in an Italian study [22]. As reported from other parts of the world, most studies support the correlation between eating raw shellfish and the risk of hepatitis A infection [2] [17] [23] [24].…”

“…In 2007, the Korean Society of Infectious Diseases recommended that all adults in their 20s should be vaccinated against hepatitis A, as well as adults in their 30s and 40s without immunity [46]. It should be noted that immunization for adult who is likely to eat raw oyster or handle food ingredients occupationally or travel overseas to HAV-endemic areas is needed to prevent spreading from an outbreak caused by HAV [21].…”