Introduction: : Most of the children in Laos who are infected with the human immunodeficiency virus (HIV) contract it through perinatal mother to child transmission (PMTCT). One major risk factor for this transmission is the maternal viral load during the peripartum period. Consequently, the maternal risk classification for MTCT, based on maternal viral load, duration of antiretroviral treatment (ART), and adherence, has been widely used but has not been universally applied in Laos. Objectives: : To evaluate the maternal clinical risk classification and perinatal mother to child transmission at Mahosot and Setthathirath Hospital. Methodology: : This retrospective descriptive study was conducted at the Infectious Diseases Department of Mahosot and Setthathirath hospitals in Vientiane Capital, Laos, from January 2016 to December 2020. Data were analysed using SPSS version 26. Results: : A total of 430 HIV-infected mothers were included in the study, with 299 (69.5%) being newly diagnosed, and 251 (58.4%) identified during pregnancy. According to the WHO classification, 70.9% were at stage 1 (asymptomatic). Among pregnant mothers, 62.1% were on the tenofovir/lamivudine/dolutegravir regimen, while 37.9% were on zidovudine/lamivudine/nevirapine. All 430 infants received zidovudine (AZT) or AZT + nevirapine as postpartum prevention, with 259 (60.2%) completing 4 weeks of AZT. In terms of risk classification, 257 (59.8%) mothers were categorized as standard risk. Overall, 53 out of 430 (12.3%) children were diagnosed with HIV infection at 18 months of age. The MTCT rate was 3 out of 257 (1.2%) for mothers in the standard-risk group and 50 out of 173 (28.9%) for those in the high-risk group. Conclusion: The HIV PMTCT rate in Laos remains high, especially among HIV-infected mothers at high risk. Therefore, early detection of HIV infection, prompt initiation of ART in HIV-infected pregnant women, and the use of risk classification to select postpartum prophylaxis regimens are crucial steps in reducing the number of new HIV-infected infants in Laos.

Background: : Cancer patients with febrile neutropenia (FN) at risk of life-threatening sepsis, and require immediate empirical antibiotic therapy. Appropriate empirical therapy is a key factor for the management. 48% to 60% of childhood cancer patients with FN have infections. Bacteremia was found in 10-50% of all patients with febrile neutropenia. Objective: : To investigate the causative bacteremia Pathogens in children with cancer during febrile neutropenia at children hospital, Vientiane, Lao PDR. Methods: : A cross-sectional descriptive study was conducted to investigate the bacterial pathogens responsible for febrile neutropenia (FN) in children under 15 years of age undergoing chemotherapy for cancer. The study was carried out at the Department of Pediatric Hemato-oncology, Children's Hospital, Vientiane, Laos, from October 2021 to September 2022. Results: : A prospective study involving 162 FN episodes was undertaken. The most prevalent underlying malignancy was acute lymphoblastic leukemia (ALL), accounting for (78.40%) of cases. Clinical presentations associated with FN included pneumonia 21%. Febrile neutropenia without an identified source accounted for 58.02% of FN episodes. Severe neutropenia was observed in 59.88% of FN episodes. The frequency of bacteremia was 19.14%. Gram-negative organisms constituted 83.87% of infections, with E. coli being the most frequently isolated pathogen 29.03%. Other gram-negative organisms included Klebsiella pneumoniae, Pseudomonas aeruginosa, Burkholderia pseudomallei, and Acinetobacter baumannii. Fifty percent of E. coli and K. pneumoniae exhibited extended-spectrum beta-lactamase (ESBL) production. All ESBL-producing organisms were susceptible to meropenem and amikacin. Gram-positive organisms accounted for 16.13% of infections, with methicillin-resistant Staphylococcus aureus (MRSA) being the most prevalent 6.45%. Half of the Gram-negative organisms showed sensitivity to ceftazidime, and they were all 100% sensitive to aminoglycosides, particularly amikacin and meropenem. Conclusion: Within the context of febrile neutropenia, the frequency of bacteremia was found to be 19.14%. The most common primary causative organism was E. coli. Based on these findings, we recommend that for low-risk patients with FN, the initial empiric antibiotic regimen should consist of ceftazidime and amikacin. For high-risk patients or those hospitalized for extended periods, the most suitable empiric antibiotic regimen is meropenem combined with amikacin.

Rationale and Background: : Hepatitis B virus (HBV) vaccine has been developed in early 1980s and shown good efficacy. However, children with HIV infection had poor immune response to many kinds of vaccines. Objectives: : To assess the persistence of vaccine immunity against HBV after the primary vaccination in infancy and the response to revaccination in HIV-infected children in Mahosot hospital. Methodology: : This study was prospectively conducted in HIV-infected children at Mahosot hospital from September 2021 to August 2022. Seventy HIV-infected children were enrolled. Inform consent was performed before starting the study. Anti-HBs was checked, if anti-HBs≥10 mIU/mL, the subjects would not receive booster dose for Hepatitis B vaccine. If anti-HBs<10 mIU/mL, the patient will receive one booster dose and checked for anti-HBs 4-8 weeks after. If anti-HBs was still<10 mIU/mL, another 2 booster doses will be given and anti-HBs is checked 4-8 weeks after. Results: : We enrolled 70 HIV-infected children, most of them were older than 10 years (median=12.5). The mean age at diagnosis of HIV was 2.9 years. Sixty-seven (95.7%) had anti-HBs titer <10 mIU/mL at baseline (first visit). After the first booster, 18(26.9%) had anti-HBs titer ≥10 mIU/mL. In 49 subjects who had anti-HBs <10 mIU/mL after the first dose and received another 2 booster HBV doses, 10(20.4%) still had anti-HBs <10 mIU/mL. Anti-HBs titers at baseline, after 1st booster and after 3rd booster were5.2, 8.2, and 30mIU/mL, respectively. Conclusion: In HIV-infected children who received primary series of HBV vaccine, almost all of them (95.7%) had anti-HBs lower than seroprotective level (<10 mIU/mL). Only one fourth achieved seroprotective level after the 1st booster but 79.6% achieved seroprotective level after the 3rd booster. The results suggested that HIV-infected children should receive 3 doses of HBV revaccination.