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Background: Although Plasmodium vivax (P. vivax) malaria is in the pre-elimination phase in the Republic of Korea (ROK), it continues to affect children and adolescents, who account for approximately 4–6% of the 300 to 500 annual cases. Despite this, research focusing on P. vivax malaria in this particular population remains limited. This study investigates the clinical characteristics of pediatric P. vivax malaria in the ROK from 2000 to 2016. Methods: We retrospectively analyzed pediatric patients aged 0–18 years, diagnosed with P. vivax malaria in five hospitals in Goyang City and Seoul. Data on demographics, clinical presentations, treatment regimens, and outcomes were collected. Statistical analyses were performed for comparisons between severe and non-severe cases, across age groups, and assessing trends over time. Results: A total of 156 pediatric cases of indigenous P. vivax malaria were diagnosed. The median patient age was 13 years (men: 64.7%). Severe malaria occurred in 13.5% patients, predominantly in adolescents aged 15–18 years. The most common severe manifestations were jaundice (57.1%) and anemia (33.3%). In the ROK, the treatment regimen for pediatric P. vivax malaria involves oral administration of chloroquine at a dose of 25 mg base/kg divided over 3 days, followed by primaquine at a dose of 0.3 mg/kg for 14 days. Although all patients received chloroquine, a higher proportion of younger patients received a dose less than 25 mg/kg (87.5%, 85.5%, and 58.6% of those aged 0–4, 5–14, and 15–18 years, respectively; p < 0.001). Parasite clearance time (PCT) increased over the years, suggesting a potential decline in the chloroquine sensitivity of P. vivax. No deaths or significant long-term complications were reported. Conclusions: Pediatric P. vivax malaria showed a low incidence of severe cases and no mortality in the ROK. Underdosing of antimalarial drugs was observed, underscoring the need for educating healthcare providers to ensure appropriate dosing. Increasing PCT highlights the need for ongoing surveillance of drug efficacy in this population. Further research on the evolving sensitivity of P. vivax and improved treatment protocols is thus essential. [ABSTRACT FROM AUTHOR]

Molecular epidemiology can help clarify the properties and dynamics of HIV-1 transmission networks in both global and regional scales. We studied 143 HIV-1-infected individuals recruited from four medical centers of three cities in South Korea between April 2013 and May 2014. HIV-1 env V3 sequence data were generated (337-793 bp) and analyzed using a pairwise distance-based clustering approach to infer putative transmission networks. Participants whose viruses were ≤2.0% divergent according to Tamura-Nei 93 genetic distance were defined as clustering. We collected demographic, risk, and clinical data and analyzed these data in relation to clustering. Among 143 participants, we identified nine putative transmission clusters of different sizes (range 2-4 participants). The reported risk factor of participants were concordant in only one network involving two participants, that is, both individuals reported homosexual sex as their risk factor. The participants in the other eight networks did not report concordant risk factors, although they were phylogenetically linked. About half of the participants refused to report their risk factor. Overall, molecular epidemiology provides more information to understand local transmission networks and the risks associated with these networks.

Plasmodium vivax is the only form of malaria indigenous to South Korea (1); combination chloroquine and primaquine therapy has been the mainstay of vivax malaria treatment. After P. vivax reemerged [...]

Less costly but still accurate methods for monitoring HIV treatment response are needed. We prospectively evaluated if a qualitative polymerase chain reaction (PCR) amplification assay for virologic monitoring could maintain accuracy while reducing costs in Seoul, South Korea. We conducted the first prospective study comparing a qualitative PCR amplification of HIV-1 reverse transcriptase (RT) versus a commercial real time PCR assay (i.e., viral load) for virologic monitoring of 150 patients receiving antiretroviral therapy (ART) between November 2011 and August 2012 at an urban hospital in Seoul, South Korea. A total of 215 blood plasma samples from 150 patients receiving ART for more than 6 months were evaluated. Using the individual viral load assay, 12 of 215 (5.6%) plasma samples had more than 500 HIV RNA copies/ml. The qualitative PCR amplification assay detected individual samples with ≥500 HIV RNA copies/ml with 100% sensitivity. The specificities of the qualitative PCR amplification of the HIV-1 RT assay were 94.1%, 93.6%, and 93.2% compared to the real time PCR at 500, 1,000, and 5,000 threshold of HIV RNA copies/ml, respectively, and $24,940 USD would have been saved for 150 patients during 10 months. The qualitative PCR amplification of the HIV-1 RT assay might be a useful approach to effectively monitor patients receiving ART and save resources.

BackgroundThere have been various efforts to identify less costly but still accurate methods for monitoring the response to HIV treatment. We evaluated a pooling method to determine if this could improve screening efficiency and reduce costs while maintaining accuracy in Seoul, South Korea.MethodsWe conducted the first prospective study of pooled nucleic acid testing (NAT) using a 5 minipool + algorithm strategy versus individual viral load testing for patients receiving antiretroviral therapy (ART) between November 2011 and August 2012 at an urban hospital in Seoul, South Korea. The viral load assay used has a lower level of detection of 20 HIV RNA copies/ml, and the cost per assay is US$ 136. The 5 minipool +algorithm strategy was applied and 43 pooled samples were evaluated. The relative efficiency and accuracy of the pooled NAT were compared with those of individual testing.ResultsUsing the individual viral load assay, 15 of 215 (7%) plasma samples had more than 200 HIV RNA copies/ml. The pooled NAT using the 5 minipool + algorithm strategy was applied to 43 pooled samples; 111 tests were needed to test all samples when virologic failure was defined at HIV RNA ≥ 200 copies/ml. Therefore, 104 tests were saved over individual testing, with a relative efficiency of 0.48. When evaluating costs, a total of US$ 14,144 was saved for 215 individual samples during 10 months. The negative predictive value was 99.5% for all samples with HIV RNA ≥ 200 copies/ml.ConclusionsThe pooled NAT with 5 minipool + algorithm strategy seems to be a very promising approach to effectively monitor patients receiving ART and to save resources.

BackgroundMultiple prevention measures have the possibility of impacting HIV incidence in South Korea, including early diagnosis, early treatment, and pre-exposure prophylaxis (PrEP). We investigated how each of these interventions could impact the local HIV epidemic, especially among men who have sex with men (MSM), who have become the major risk group in South Korea. A mathematical model was used to estimate the effects of each these interventions on the HIV epidemic in South Korea over the next 40 years, as compared to the current situation.MethodsWe constructed a mathematical model of HIV infection among MSM in South Korea, dividing the MSM population into seven groups, and simulated the effects of early antiretroviral therapy (ART), early diagnosis, PrEP, and combination interventions on the incidence and prevalence of HIV infection, as compared to the current situation that would be expected without any new prevention measures.ResultsOverall, the model suggested that the most effective prevention measure would be PrEP. Even though PrEP effectiveness could be lessened by increased unsafe sex behavior, PrEP use was still more beneficial than the current situation. In the model, early diagnosis of HIV infection was also effectively decreased HIV incidence. However, early ART did not show considerable effectiveness. As expected, it would be most effective if all interventions (PrEP, early diagnosis and early treatment) were implemented together.ConclusionsThis model suggests that PrEP and early diagnosis could be a very effective way to reduce HIV incidence in South Korea among MSM.

We reviewed the clinical efficacy of chloroquine for Plasmodium vivax malaria, the changing trend of parasite clearance time, and fever clearance time during 2000-2016 in South Korea. Median parasite clearance time and fever clearance time increased significantly over the study period. Chloroquine was mostly underdosed when used to treat P. vivax malaria. [ABSTRACT FROM AUTHOR]