The changing epidemiology of hepatitis A in children and the consideration of active immunization in Korea

Currently, Korea is a low endemicity country for HAV, especially in children. However, recent reports of hepatitis A outbreaks show that there has been a shift of disease incidence to adolescents and young adults, with 2 cases of acute liver failure in one reported outbreak. We need to study the immune status for HAV in order to provide information for the establishment of preventive measures and possible consequences of HAV in Korea. A total of 334 infants, children and adolescents less than 20 years of age living in rural areas of Kyonggi Province, Korea were evaluated for anti-HAV immune status in 1996. Five hundred and eighty-four primary school children living in the same area were separately evaluated for the natural seroconversion rate between 1993 and follow-up samples taken in 1996. Anti-HAV IgG antibody was measured by enzyme immunoassay (HAVAB EIA kit, Abbott Laboratories, Chicago, Illinois, USA). In comparison with previous reports of seroprevalence rates, our data confirmed a dramatic drop in seroprevalence rates among children and adolescents under 20 years of age living in rural areas, from over 63.8% two decades ago to 4.6% in 1996. Natural acquisition of HAV antibody in primary school children rarely occurs, registering only 0.5% during three years. Several outbreaks in young adults during 1996-1998 suggested that immunity against HAV in this population is so low that massive outbreaks are unavoidable. Teenagers and young adults, especially soldiers, who are likely to be exposed to contaminated food or water, would also have a greater risk of hepatitis A. Immunizing children with HAV vaccine as a routine schedule should also be considered in Korea in the future, particularly if the disease burden could be estimated and the cost-effectiveness of the vaccine could be proved.

Immune Response to SA14-14-2 Live Attenuated Japanese Encephalitis Vaccine

PURPOSE: SA14-14-2 live attenuated Japanese encephalitis (JE) vaccine has been administered safely and effectively to more than 100 million children in China since 1988, and recently licensure of the vaccine in Korea has been sought. Immune response to the vaccine was investigated. MEHTODS: In the first clinical evaluation of the vaccine outside of China, we monitored side effects in 93 children and evaluated plaque reduction neutralizing test (PRNT) antibody and IgM antibody responses to a single dose given as primary JE vaccination in 74 children, 1-3 years old (mean age 27 months). RESULTS: No significant adverse events were noted. PRNT antibodies (geometric mean titer [GMT] of 183) were produced in 96% of the 74 subjects. In 10 other children who previously had been immunized with two or three doses of inactivated JE vaccine, the booster administration of SA14-14-2 vaccine produced an anamnestic response in all, with a GMT of 3378. In a comparison group of 25 children previously immunized with two doses of inactivated vaccine, neutralizing antibody titers were detected in 16 (64%). Viral specific IgM was detected in nine primary vaccinees (13%) but in others, IgM may have declined to undetectable levels in the four week postimmunization sample. CONCLUSION: Live attenuated SA14-14-2 JE vaccine is a promising alternative to the only commercially available live attenuated JE vaccine for national childhood immunization programs in Asia.

A Case of Congenital Tuberculosis

Perinatal tuberculosis can be divided into congenital tuberculosis due to intrauterine infection and neonatal tuberculosis due to infection irnmediately following birth. It is a rare disease entity with only 300 cases reported worldwide. In Korea, only a few cases have been reported and only 1 case has been confirmed by autopsy at neonatal period. Although the majority of the mothers are found to have advanced tuberculosis and the children themselves are usually of premature birth, early diagnosis is difficult and despite antituberculous medication, the mortality rate is high. We report a premature baby with respiratory difficulty admitted to our hospital, whose mother was found to have miliary tuberculosis during the course of management. The baby died and autopsy was performed to confirm congenital tuberculosis.

Increase in IL-6 and Number of Inflammatory Cells in the Lung Lavage Fluid of Adult Mice Exposed to 95% Oxygen: Protective Effect of Budesonide

PURPOSE: Pulmonary oxygen toxicity is mainly an inflammatory process, triggered by reactive oxygen species via a number of biochemical pathways. Recent evidence implies that ROS may stimulate NF-Kb to promote the synthesis of genes for inflammatory cytokines. At the same time, corticosteroids have been implicated in the prevention of activating this step. However, adverse reactions of systernic corticosteroids cause physicians to hesitate their use, not to mention their doubtful effectiveness. Budesonide is a locally acting corticosteroid with little systemic effect. Inhaled either through nebulizers or metered dose inhalers, it has proved the antiinflammatory, and thus antiasthmatic, effects in patients with asthma. If oxygen-induced injury is mediated by factors involved in a similar pathway as described above, budesonide will have protective effects against inflammatory responses of pulmonary oxygen toxicity. METHODS: We used 10 adult mice in each of the three groups, AC is the room air control group, OC is the oxygen control group in which mice were exposed to 95% oxygen for 48 h; and TX is the treatment group in which mice were exposed to 95% oxygen for 48 h, and during that period they were given budesonide via a nebulizer 500 p g/dose every 12 h for 4 times. The mice were sacrificed with iection of a lethal dose of ketamine. Tracheotomy was done and an 18G ET tube was inserted. The lungs were lavaged with 80 ml/kg(or 80 microliter/g) isotonic saline slowly injected through the ET tube. The lung lavage fluid was centrifuged at 8000 rpm for 2 rninutes. Supernatant was used for analysis of IL-6, while the precipitate was resuspended in 200 microliter of isotonic saline for cell count. RESULTS: The simple mean IL-6 values did not show a significant difference between groups (AC 199.4+/-192.7; OC 274.5+/-31.3; and TX 269.8+/-127.G pg/Ml). But considering their skewed distribution in AC and TX groups, the median values showed a conspicuous difference among 3 groups, that is, the median IL-6 value of AC was 124.8 pg/Ml, OC 269.8 pg/Ml, and TX 217.4 pglmL. For the cell counts, AC was 189+/-56/mm, OC 424+/-111/mm, and TX 266+/-22/mm(P<0.05). CONCLUSION: In conclusion, budesonide nebulization appears to have protective effects against inflammatory responses of pulmonary oxygen toxicity in adult mice.