The costs of hepatitis A infections in South Korea

The chronological changes in the seroprevalence of anti-hepatitis A virus IgG from 2005 to 2019: Experience at four centers in the capital area of South Korea

Although universal vaccination has been administered to toddlers, South Korea has had periodic nationwide outbreaks of acute hepatitis A since the late 2000s. We examined the chronological changes in the seroprevalence of anti-hepatitis A virus (HAV) immunoglobulin G (IgG) over the past 15 years (2005-2019). We retrospectively collected data from 45,632 subjects who underwent anti-HAV IgG testing without evidence of acute HAV infection at four centers in the capital area of South Korea between January 2005 and December 2019. The seroprevalence of anti-HAV IgG was analyzed according to age and compared among seven age groups and five time periods. Additionally, age-period-cohort analyses were used to identify the age, period, and cohort effects of the seroprevalence of anti-HAV IgG. The mean age of the enrolled subjects was 39.2 ± 19.2 years, and the average anti-HAV IgG positivity rate was 66.4%. During the 15 years, the seroprevalence of anti-HAV IgG in people aged 0 to 19 years significantly increased over time (P < .001). In people aged 20 to 29 years, the seroprevalence slightly decreased to that of the early 2010s (31.3% in 2005-2007 to 19.7% in 2011-2013) but rebounded to 39.5% in 2017 to 2019. In contrast, the seroprevalence of anti-HAV IgG in those aged 30 to 49 years decreased over time (P < .001). The seroprevalence of anti-HAV IgG in those aged 20 to 39 years in 2017 to 2019 was still less than 40%. In addition, the seroprevalence of anti-HAV IgG in people aged 50 to 59 years has recently decreased. Since the introduction of the universal vaccination, the seroprevalence of anti-HAV IgG in children and young adults has gradually increased. However, the seroprevalence of anti-HAV IgG in people in their 20s remains low, and the seroprevalence of anti-HAV IgG in people in their 30s and 40s is gradually decreasing. Therefore, a new strategy for HAV vaccination is needed for those in their 20s to 40s.

Hepatitis A Outbreak in a Facility for the Disabled, Gyeonggi Province, Korea: An Epidemiological Investigation

Objectives:

The number of cases of hepatitis A virus (HAV) infections has sharply increased in Korea, especially among young adults. In this study, an HAV outbreak in a facility for disabled people was investigated, and we found epidemiological differences both between 2 different generations and between generally abled and disabled groups.

Methods:

We analyzed the incubation period and attack rate of an HAV outbreak and investigated the prevalence of HAV antibodies among the staff and residents of a facility for the disabled. We performed a retrospective cohort study during the HAV outbreak, which lasted from February 8 to 25, 2019, including examinations of HAV antibody tests and post-exposure HAV vaccination for the staff or residents of the facility.

Results:

There were 9 confirmed cases in 2 staff members and 7 residents. Among 53 people (30 staff and 23 residents), except for the 9 confirmed cases and 1 staff member with a known history of HAV infection, HAV seroprevalence was seen in 16.7% of the staff under 40 years of age and 95.2% of those over 40 years of age, while the corresponding rates in the residents were 0.0% and 58.8%, respectively.

Conclusions:

This result implies that it is necessary to prioritize HAV vaccination for vulnerable groups and workers of residential care facilities.

Seropositive rate of the anti-hepatitis A immunoglobulin G antibody in maintenance hemodialysis subjects from two hospitals in Korea

BACKGROUND/AIMS

Hepatitis A virus (HAV) is a self-limiting infectious disease, but 1% of subjects develop fulminant hepatitis. The prevalence of the anti-HAV immunoglobulin G (IgG) antibody in hemodialysis subjects in Korea remains unknown. The purpose of this study was to describe and compare the seropositive rate of anti-HAV antibody among hemodialysis subjects in two hospitals according to age group.

METHODS

A total of 170 hemodialysis subjects were evaluated for the seropositive rate of the anti-HAV IgG antibody and its titer.

RESULTS

Of the 170 maintenance hemodialysis subjects in two hospitals (Kangnam 92 vs. Chuncheon 78), 79 (46.5%) were male. The mean age was 53.2 years old, and 94.1% of the subjects were over 40 years old. The median vintage of hemodialysis was 29.0 months. Anti-HAV antibody was found in 163 subjects (95.9%), with no significant difference between the two areas (Kangnam 97.8% [n = 90] vs. Chuncheon 93.6% [n = 73]). Subjects younger than 40 years old showed a seropositive rate of 50%, while the seropositive rate increased with age for subjects aged 40 or older (p for trend < 0.001). Seropositive subjects from Kangnam showed a higher anti-HAV antibody titer than those from Chuncheon (median: Kangnam 14.2 vs. Chuncheon 11.7). Only age influenced seropositivity. The only factor that influenced the antibody level was the location of hospital (p < 0.001).

CONCLUSION

The seropositive rate of the anti-HAV antibody in hemodialysis subjects was 95%, which is similar to findings in the general population. Active immunization against hepatitis A is strongly recommended for hemodialysis subjects under 40 years of age after anti-HAV testing.

Perspectives on Acute Hepatitis A Control in Korea

Until 1995, the incidence of symptomatic acute hepatitis A was minimal and there were no cases of national outbreak in Korea. However, there was a nationwide outbreak of hepatitis A that peaked in 2009. In 2019, a total of 10,083 cases of acute hepatitis A were reported for seven months of the year according to the Korea Center for Disease Control and Prevention. This may be attributed to the proportion of susceptible subjects in the Korean population, as about 10 years have passed since herd immunity was induced by the epidemic occurring during the late 2000s. Recent studies have shown that the rate of seropositivity for anti-hepatitis A virus antibodies (anti-HAV) is the lowest in adults in their 20s and has not changed much over the past 10 years, and seropositivity of anti-HAV in adults in their 30s has continued to decline from 69.6% in 2005 to 32.4% in 2014. Most young adults who have not yet experienced hepatitis A and are not vaccinated are vulnerable to hepatitis A infection. This year's epidemic of hepatitis A is a predictable outcome for vulnerable populations. Therefore, effective acute hepatitis A control and prevention strategies are needed, particularly for those in their 20s and 30s.

Causes and countermeasures for repeated outbreaks of hepatitis A among adults in Korea

The 2019 hepatitis A outbreak has become increasingly prevalent among adults in Korea and is the largest outbreak since that in 2009-2010. The incidence in the current outbreak is highest among adults aged 35-44 years, corresponding to the peak incidence among those aged 25-34 years 10 years ago. This may indicate a cohort effect in the corresponding age group. Causes of these repeated outbreaks of hepatitis A in Korea are low level of immunity among adults, Korean food culture that consumes raw seafood such as salted clam and inadequate public health system. Among countermeasures, along with general infectious disease control measures including control of the infectious agent, infection spread, and host, urgent actions are needed to review the vaccination policy and establish an adequate public health system.

Estimating the Incidence of Cases and Deaths Resulting from Hand, Foot and Mouth Disease and Its Related Socioeconomic Disease Burden in Republic of Korea (2010 - 2014)

Objectives

Hand, Foot and Mouth disease (HFMD) is a highly contagious viral disease that affects young children and frequently causes epidemics. A vaccine is available in China (enterovirus 71) and, the Republic of Korea took the first step to develop a new vaccine. New vaccine development requires that disease burden is calculated in advance so the financial cost, morbidity and mortality can be measured.

Methods

Data from National Sentinel Surveillance and health insurance systems of 1 million claimants were used. Direct medical and non-medical costs, indirect (caregiving and premature death) costs, cases and related deaths were summarized.

Results

From 2010 to 2014, there were an estimated 3,605 to 9,271 cases of HFMD, with 1 to 3 deaths. The estimated socioeconomic disease burden ranged from 80.5 to 164.2 million USD and was similar to that of hepatitis A (93.6-103.8 million USD). Among each costs, costs of caregiving consisted of highest proportion mainly due to hiring caregivers (50% - 60%) or opportunity costs from day off (62% - 69%).

Conclusion

Considering the social impact of HFMD, the estimated socioeconomic disease burden is not high and government policies need to focus on reducing the loss of work in caregivers.

Viral Hepatitis in South Korea

In South Korea (S. Korea), viral hepatitis is a major public health burden. Advances in healthcare policy, evidence-based medicine, and therapeutic strategies in S. Korea have brought a rapid change in the sociodemographic and clinical characteristics of viral hepatitis. This review discusses the innovative approaches that S. Korea has taken to curb the epidemic of viral hepatitis. In addition, the efficacy of various preventive and therapeutic modalities is discussed. This review aims to provide a brief overview to guide future research direction and healthcare policy changes.

How to cite this article: Pak SC, Alastal Y, Khan Z, Darr U. Viral Hepatitis in South Korea. Euroasian J Hepato-Gastroenterol 2017;7(2):163-165.