Explore the vast range of titles available.

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus of significant public health concern. ZIKV shares a high degree of sequence and structural homology compared with other flaviviruses, including dengue virus (DENV), resulting in immunological cross-reactivity. Improving our current understanding of the extent and characteristics of this immunological cross-reactivity is important, as ZIKV is presently circulating in areas that are highly endemic for dengue. To assess the magnitude and functional quality of cross-reactive immune responses between these closely related viruses, we tested acute and convalescent sera from nine Thai patients with PCR-confirmed DENV infection against ZIKV. All of the sera tested were cross-reactive with ZIKV, both in binding and in neutralization. To deconstruct the observed serum cross-reactivity in depth, we also characterized a panel of DENV-specific plasmablast-derived monoclonal antibodies (mAbs) for activity against ZIKV. Nearly half of the 47 DENV-reactive mAbs studied bound to both whole ZIKV virion and ZIKV lysate, of which a subset also neutralized ZIKV. In addition, both sera and mAbs from the dengue-infected patients enhanced ZIKV infection of Fc gamma receptor (FcγR)-bearing cells in vitro. Taken together, these findings suggest that preexisting immunity to DENV may impact protective immune responses against ZIKV. In addition, the extensive cross-reactivity may have implications for ZIKV virulence and disease severity in DENV-experienced populations.

This retrospective observational study assesses the clinical characteristics, atypical manifestations, and treatment outcomes in pediatric patients hospitalized with chikungunya virus (CHIKV) infection during the Bangkok outbreak in 2019. Children <18 years old hospitalized from January 1 to December 31, 2019, and confirmed positive for CHIKV infection by RT-PCR or IgM antibodies were included in this study at a tertiary care center in Bangkok, Thailand. Patient demographics, clinical manifestations, and laboratory findings at the time of hospitalization were collected from de-identified medical records. Of 31 included children, seven (22.6%) were <1 year old, 22 (71.0%) were male, nine (29.0%) had underlying medical conditions, four (17.4%) tested positive for dengue coinfection, and four (12.9%) had multi-organ involvement. The median age was 9.5 (IQR 6.9–12.5) years. Most (90.3%) had atypical clinical manifestations, four (12.9%) had life-threatening manifestations. Two (6.5%) neonates had congenital CHIKV. The most common manifestations included fever (100.0%), rashes (77.4%), myalgia (41.9%), and arthralgia (35.5%). The three most involved organ systems presenting atypical manifestations included gastrointestinal (32.3%), dermatologic (32.3%), and neurological (22.6%) systems. Of those with dermatologic involvement, 67.7% had maculopapular rashes, 19.4% bullous skin lesions, and 6.5% generalized erythroderma. At the time of presentation, 25 (80.6%) children had lymphopenia, five (16.1%) had anemia, and none had thrombocytopenia. Five (16.1%) children required intensive care and four (12.9%) developed shock. Thirteen (41.9%) children, five with neurological involvement, fully recovered at discharge. Among the remaining children, five (16.1%) still had musculoskeletal conditions, 11 (35.5%) had skin lesions, and two (6.5%) with congenital CHIKV had skin lesions and neurological sequelae. Despite the small cohort, the observed frequency of neurological complications attributed to CHIKV infection justifies long-term follow-up in children with neurological manifestations and complications. CHIKV should be suspected in endemic countries and tested for in febrile children, particularly those with rash and neurological involvement.

Background Measuring the maximum occipitofrontal circumference only once at birth or within 24 h after birth may lead to misclassifications of microcephaly. This study compared the head circumference (HC) of newborns at birth or within 24 h after birth to their third day of life (DOL3) as well as evaluated maternal- and infant-specific factors associated with increased HC by DOL3. Methods This prospective study included 1131 live births between February and May 2019 with a gestational age > 27 weeks. All newborns had their HC measured at birth or within 24 h after birth as well as on DOL3 before discharge. HC measurements were performed by trained personnel using non-elastic tape measures. The World Health Organization (WHO) and Fenton Growth Charts were used as reference ranges for interpretation of full-term and preterm neonates, respectively. Results Paired sample t-test analyses found a statistically significant increase in HC measured on the DOL3 compared with HCs of the same newborns at birth or within 24 h of birth. The mean HC increase was 0.17 cm (95% confidence interval [0.13, 0.21], P  < 0.001). The mean ± standard deviation HC within 24 h of birth and at DOL3 were 33.58 ± 1.53 cm and 33.75 ± 1.37 cm, respectively. Thirty-two newborns had HCs less than the third percentile (< P3) at birth, 25 of which had HC ≥ P3 at DOL3. After adjusting for mode of and presentation at delivery, newborns whose mothers experienced labor pains (β = 0.31, P  < 0.001) and were either symmetrically (β = 0.59, P  = 0.002) or asymmetrically small-for-gestational age (SGA; β = 0.37, P  = 0.03) had significantly increased HC at DOL3. On average, newborns whose mothers experienced labor pain had 0.31 cm increases in HC at DOL3. Symmetrical SGA newborns also had an average 0.59 cm increase in HC at DOL3. Parity and gestational age were not associated with changes in HC. Conclusions Serial HC measurements on DOL3 or before newborns’ discharge is crucial to classifying congenital microcephaly.

Little is known about the regulation of B cell subpopulations in association with programmed cell death during dengue virus (DENV) infection. Therefore, blood samples from dengue-infected patients and healthy donors were obtained for B cell subset characterization and the analysis of pro-apoptotic CD95 expression in these cell subsets. The results showed that the activated memory (AM) subset in the patients remained unchanged compared to the healthy donors. In contrast, tissue memory (TM) and antibody-secreting cells (ASCs) were notably increased, whereas naïve cells and resting memory (RM) cells were considerably decreased. Although the ASCs maintained comparably high levels of CD95 expression in both groups, significantly increased percentages of CD95-expressing cells in the other B cell subsets were found in the patients. When B cells from the healthy donors were treated with DENV non-structural protein 1 (NS1), the results showed that the NS1 protein at 2 µg/mL could induce CD95 expression and the exposure of phosphatidylserine on the cell membrane in most B cell subsets, except for the RM. This study demonstrates that DENV infection could induce CD95 expression in both activated and resting B cell subsets in all patients. The results also suggest a potential mechanism of apoptotic regulation in B cell subsets through the increased CD95 expression caused by the interaction between the B cells and the NS1 protein.

Respiratory syncytial virus (RSV) infection is the leading cause of infant hospitalizations and mortality. Lumicitabine, an oral nucleoside analog was studied for the treatment of RSV. The phase 1b and phase 2b studies reported here assessed the safety, pharmacokinetics, and pharmacodynamics of lumicitabine in infants/neonates hospitalized with RSV. In the phase 1b study, infants (≥1 to ≤12 months) and neonates (<28 days) received a single-ascending or multiple-ascending doses (single loading dose [LD] then 9 maintenance doses [MD] of lumicitabine, or placebo [3:1]). In the phase 2b study, infants/children (28 days to ≤36 months old) received lumicitabine 40/20 mg/kg, 60/40 mg/kg LD/MD twice-daily or placebo (1:1:1) for 5 days. Safety, pharmacokinetics, and efficacy parameters were assessed over 28 days. Lumicitabine was associated with a dose-related increase in the incidence and severity of reversible neutropenia. Plasma levels of ALS-008112, the active nucleoside analog, were dose-proportional with comparable mean exposure levels at the highest doses in both studies. There were no significant differences between the lumicitabine groups and placebo in reducing viral load, time to viral non-detectability, and symptom resolution. No emergent resistance-associated substitutions were observed at the RSV L-gene positions of interest. In summary, lumicitabine was associated with a dose-related increase in the incidence and severity of reversible neutropenia and failed to demonstrate antiviral activity in RSV-infected hospitalized infants. This contrasts with the findings of the previous RSV-A adult challenge study where significant antiviral activity was noted, without incidence of neutropenia. Trial registration ClinicalTrials.gov Identifier: NCT02202356 (phase 1b); NCT03333317 (phase 2b).

Background Frontline healthcare workers (HCWs) faced a high risk of SARS-CoV-2 infection during the early stages of the COVID-19 pandemic. This study aims to determine the prevalence and incidence of SARS-CoV-2 infection in HCWs using various serological methods and to evaluate diagnostic reliability. Methods A prospective study was conducted on 240 frontline and 120 non-frontline HCWs at Siriraj Hospital in Bangkok, Thailand, from May 2020 to March 2021. Blood samples were collected at enrollment and at 4, 12 and 48 weeks. Three serological methods were utilized: electrochemiluminescence immunoassay (ECLIA) for qualitative anti-nucleocapsid protein antibodies, enzyme-linked immunosorbent assay (ELISA) and chemiluminescent microparticle immunoassay (CMIA) for quantitative anti-spike receptor-binding domain (RBD) antibodies. ELISA-positive samples were further analyzed with microneutralization and flow cytometry-based assays. Results One non-frontline HCW had initial positive ECLIA result but tested negative by both ELISA and CMIA. Two frontline HCWs consistently tested positive by ELISA over these 48 weeks, resulting in a seroprevalence of 0.83% (2/240) among frontline HCWs. Ten frontline and six non-frontline HCWs had borderline or positive level of anti-RBD IgG by ELISA but were negative for microneutralization. A flow cytometry-based assay suggested that these positive ELISA results were likely due to cross-reactivity from pre-existing antibodies against other human coronaviruses (HCoVs), particularly HCoV-HKU1. Conclusions An extremely low prevalence of SARS-CoV-2 infection among HCWs in Thailand at the pandemic’s outset, likely due to effective transmission control. Pre-existing antibodies against other human coronaviruses could lead to false positive serological testing for SARS-CoV-2.

There are gaps in knowledge and experience of antiretroviral pre-exposure prophylaxis (PrEP) delivery in adolescents. This pilot study enrolled Thai adolescents 14-20 year-old without HIV who reported risk behaviour. All participants were offered daily tenofovir/emtricitabine (TDF-FTC) and followed for 24 weeks. HIV testing, renal function, bone density scan, and sexually transmitted infection (STI) testing including syphilis serology and urine molecular testing for gonorrhoea and C. trachomatis were performed at baseline and weeks 12 and 24. Adherence was evaluated through intracellular tenofovir diphosphate (TFV-DP) levels in dried blood spots. Of the 61 enrolled adolescents, median age 18.1 (IQR: 14.8-20.9) years, 46 (75.4%) were males and 36 (59%) were MSM. Retention to week 24 was 80.3%. One third (36%) had TFV-DP levels consistent with taking ≥6 pills/week at week 12 and 29% at week 24. The factors associated with taking ≥6 pills/week were being MSM (adjusted odds ratio [aOR]: 53.2, 95% CI: 1.6-1811; p = 0.027), presence of STI at baseline (aOR: 9.4, 95% CI: 1.5-58.5; p = 0.016), and self-report of decreased condom use while taking PrEP (aOR: 8.7, 95% CI: 1.4-56.6; p = 0.023). 31% had an STI at baseline and this declined to 18% at week 24. No renal or bone toxicity was observed and there were no HIV seroconversions. Daily oral PrEP with FTC-TDF in high-risk Thai adolescents is feasible, accepted, well-tolerated, and had no increased risk compensation; however, low adherence was a major challenge. Adolescent-specific PrEP strategies including long-acting modalities are needed for successful HIV prevention.

Human Immunodeficiency Virus (HIV) prevalence among young gender-diverse (a wide range of gender identities for people whose gender identity is different from the sex that they were assigned at birth) individuals is high but testing coverage among this key population remains low. We aim to evaluate strategies for outreach, HIV testing, and linkage to proper management in young men-who-have-had-sex-with-men (MSM, homosexual male) and transgender women (TGW) in Bangkok, Thailand. The \"YM2M outreach program\" consisted of two strategies: 1) online platforms (OP) and 2) physical outreach activities (POA). Participant questionnaires were completed on a voluntary basis during outreach activities during 2018-2021. Demographic and behavioral characteristics were assessed for association with HIV positivity. A total of 3,972 homosexual male and TGW participated in the YM2M program: 2,973 by OP and 999 by POA. Of 2,230 participants who reported gender identity, 603/1,392 (43.3%) of OP and 252/985 (25.6%) of POA were gender diverse. Of 631 (21.2%) participants in OP and 970 (97.1%) in POA who underwent testing, 286 (45.3%) in OP and 41 (4.2%) in POA were HIV-positive. The venue reporting highest HIV yield was the Mor-Lam (11.5%). Among those with an HIV-positive test, 175 (61.2%) from OP and 23 (51.1%) from POA were successfully linked to HIV care. The independent factors associated with HIV positive in OP were being youth (adjusted odd ratio (aOR), 0.37; 95%CI 0.16-0.81; P = 0.01) and suspected or confirmed STI (aOR 15.39; 95%CI 7.17-33.03, P<0.01); while those in in POA at Mor-Lam were being gender diverse (aOR, 8.43; 95%CI 1.94-36.62; P<0.01) and reactive syphilis test (aOR, 5.40;95%CI 2.45-11.88; P<0.01). Linkage to pre-exposure prophylaxis (PrEP) among HIV-negative participants was low, 4.9% and 2.6% in OP and POA participants, respectively. While uptake of HIV testing was higher in POA while OP was more effective in identifying undiagnosed people living with HIV/AIDS and linking them to care. Neither strategy was considered effective in linkage to PrEP.

Geriatric populations are at an increased risk of severe presentations, hospitalization, and loss of life from COVID-19. Few studies have explored vaccination regimens in adults >65 years old. Repeated booster vaccination is required for high-risk populations as COVID-19 vaccine efficacy is short-lived. We compared the immunogenicity and reactogenicity of second intradermal (ID) COVID-19 booster vaccination with second intramuscular (IM) vaccination in older adults. This single-center, open-labeled, prospective, cohort study conducted at Siriraj Hospital enrolled older adults ≥65 years old who previously received a first booster (third dose) mRNA vaccine (mRNA-1273 or BNT162b2) via ID or IM administration. Participants were allocated to receive a second booster of the same vaccine type and route as their first booster 16-17 weeks thereafter. Anti-SARS-CoV-2 receptor binding domain IgG and neutralizing antibody titers against Wuhan and Omicron subvariants (BA.1, BA.2, and BA.4/5) were measured 2 weeks after vaccination. Of 91 enrolled participants, 72.5% were women, with a median age of 75 years. Forty-nine participants (53.8%) received a second ID booster, and 42 (46.2%) received a second IM booster. Two weeks after the second booster, all groups generated anamnestic IgG antibody responses that were 5.41- to 10.00-fold higher than at baseline. Overall, higher antibody GMTs against Wuhan and Omicron subvariants were observed in IM compared with ID regimens. ID mRNA-1273 induced similar GMTs to IM BNT162b2 2 weeks after the second booster against Wuhan (486.77 [321.48, 737.05] vs. 472.63 [291.24, 767.01], respectively; = 0.072). Higher GMTs against Omicron BA.1 (GMR [95% CI], 1.71 [1.39, 2.11]; = 0.023), BA.2 (1.34 [1.11, 1.62]; = 0.845), and BA.4/5 (1.10 [0.92, 1.33]; = 0.531) were seen in all groups at 2 weeks after the second booster compared with 2-4 weeks after the first booster. Both local and systemic AEs were less frequent after the second than after the first booster, regardless of administrative route and vaccine type. Local AEs were significantly more frequent in ID mRNA-1273 arms than their respective BNT162b2 arms 2 weeks after the second booster (ID-mRNA-1273 vs. ID-BNT162b2: ≤ 0.001). Repeated fractional ID vaccination may be an alternative booster vaccination strategy for geriatric populations.

Bacille Calmette-Guérin (BCG) vaccination at birth may cause mild and benign local adverse effects (AE). More serious AE are rarely reported. To describe clinical features and outcomes of BCG (Tokyo-172 strain)-induce diseases (BCG-ID) that required medical attention at a tertiary care center in Bangkok, Thailand. We retrospectively reviewed medical records from January 2007 to December 2016 that were selected by ICD-10 codes. The inclusion criteria were the patients under 3 years of age who developed lymphadenitis, osteitis, or disseminated infections of which BCG was a possible pathogen. Cases were classified into suspected (clinically compatible without laboratory confirmation), probable (suspected cases with M. tuberculosis complex identified), and confirmed BCG-ID (probable cases with molecular confirmation of M. bovis BCG strain). 95 children were identified; 57 (60.0%) were male, and the median age at presenting symptom was 3.5 (range: 0.6–28.7) months. Of these, 25 (26.3%) were suspected, 49 (51.6%) were probable, and 21 (22.1%) were confirmed BCG-ID. Overall, 87 (92%) children had regional lymphadenitis corresponding to the BCG site, 5 (5%) had osteitis, and 3 (3%) had disseminated BCG. Of those with lymphadenitis, average size was 2.2 (range 0.7–5) cm. in diameter and 53% (46/87) had pulmonary involvement. Five children with immunodeficiency; three had disseminated BCG and two had lymphadenitis. Eight (9.2%) patients with lymphadenitis underwent needle aspiration; 57 (65.5%) had surgical excision. All children with BCG osteitis underwent surgical intervention in combination with anti-tuberculosis treatment. One patient with osteitis experienced long-term leg length discrepancy. Regional lymphadenitis was the most common feature of BCG-ID requiring medical attention. That none of the BCG osteitis were immunocompromised hosts suggested the potential virulence of BCG in neonates. A systematic national surveillance and reporting system is needed to develop accurate estimates of population incidence and support development of effective vaccine policy.