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ABSTRACTThe surge in coronavirus disease 2019 (COVID-19) caused by the Omicron variants of the severe acute respiratory syndrome coronavirus 2 necessitates researches to inform vaccine effectiveness (VE) and other preventive measures to halt the pandemic. A test-negative case–control study was conducted among adults (age ≥18 years) who were at-risk for COVID-19 and presented for nasopharyngeal real-time polymerase chain reaction testing during the Omicron variant-dominant period in Thailand (1 January 2022–15 June 2022). All participants were prospectively followed up for COVID-19 development for 14 days after the enrolment. Vaccine effectiveness was estimated and adjusted for characteristics associated with COVID-19. Of the 7971 included individuals, there were 3104 cases and 4867 controls. The adjusted VE among persons receiving 2-dose, 3-dose, and 4-dose vaccine regimens for preventing infection and preventing moderate-to-critical diseases were 33%, 48%, 62% and 60%, 74%, 76%, respectively. The VE were generally higher among those receiving the last dose of vaccine within 90 days compared to those receiving the last dose more than 90 days prior to the enrolment. The highest VE were observed in individuals receiving the 4-dose regimen, CoronaVac-CoronaVac-ChAdOx1 nCoV-19-BNT162b2 for both preventing infection (65%) and preventing moderate-to-critical diseases (82%). Our study demonstrated increased VE along with an increase in number of vaccine doses received. Current vaccination programmes should focus on reducing COVID-19 severity and mandate at least one booster dose. The heterologous boosters with viral vector and mRNA vaccines were highly effective and can be used in individuals who previously received the primary series of inactivated vaccine.

Data on real-life vaccine effectiveness (VE), against the delta variant (B.1.617.2) of the severe acute respiratory syndrome coronavirus 2 among various coronavirus disease 2019 (COVID-19) vaccine regimens are urgently needed to impede the COVID-19 pandemic. We conducted a test-negative case-control study to assess the VE of various vaccine regimens for preventing COVID-19 during the period when the delta variant was the dominant causative virus (≥ 95%) in Thailand (25 July 2021–23 Oct 2021). All individuals (age ≥18 years) at-risk for COVID-19, presented for nasopharyngeal real-time polymerase chain reaction (RT-PCR) testing, were prospectively enrolled and followed up for disease development. Vaccine effectiveness was estimated with adjustment for individual demographic and clinical characteristics. Of 3353 included individuals, there were 1118 cases and 2235 controls. The adjusted VE among persons receiving two-dose CoronaVac plus one BNT162b2 booster was highest (98%; 95% confidence interval [CI] 87–100), followed by those receiving two-dose CoronaVac plus one ChAdOx1 nCoV-19 booster (86%; 95% CI 74–93), two-dose ChAdOx1 nCoV-19 (83%; 95% CI 70–90), one CoronaVac dose and one ChAdOx1 nCoV-19 dose (74%; 95% CI 43–88) and two-dose CoronaVac (60%; 95% CI 49–69). One dose of CoronaVac or ChAdOx1 nCoV-19 had a VE of less than 50%. Our study demonstrated the incremental VE with the increase in the number of vaccine doses received. The two-dose CoronaVac plus one BNT162b2 or ChAdOx1 nCoV-19 booster regimens was highly effective in preventing COVID-19 during the rise of delta variant.

Objective: To compare the prevalence of HS and quality of life in non-transfusion dependent thalassemia (NTDT) and Transfusion dependent thalassemia (TDT) patients and to identify risk factors associated with HS in pediatric thalassemia. Materials and Methods: We conducted a cross-sectional study of pediatric thalassemic patients aged from 6 months - 18 years between January 2020 and October 2020, at Thammasat University Hospital, Thailand. Results: There were 141 thalassemia patients (35 TDT and 106 NTDT), aged 7 months-18 years, 73 (51.8%) were male. Sixty-eight patients (48.2%) reported snoring; 28 patients (19.9%) had HS; the remaining 40 patients (28.4%) had simple snoring. The prevalence of HS was not significantly different between TDT and NTDT group (6 (17.1%) VS 22 (20.8%); P= 0.527). Quality of life assessed by OSA-18 score was not significant difference between TDT and NTDT groups (51.3 ± 18.8 VS 45.7 ± 11.4; P=0.141). The associating risk factors for the development of HS after multivariate logistic analysis were nasal congestion, and male gender, with an adjusted OR of 5.3 and 3.0, respectively. Conclusion: Prevalence of HS was increased in children with thalassemia. Factors such as nasal congestion and male gender were strongly associated with HS in this population. The quality of life assessment using the OSA-18 questionnaire indicated that thalassemia children generally exhibited a good quality of life. Additionally, our study observed relatively low serum ferritin levels in comparison to previous studies. The standard care provided for TDT patients, includes regular blood transfusion and effective iron chelation, may contribute to slowing down the degree of nasopharyngeal narrowing in thalassemia patients.

Introduction: Many clinicians hesitate adopting a universal infant iron supplementation program due to the risk of increased iron absorption for those with thalassemia. We aimed to determine thalassemia prevalence in 6- to 12-month old infants, along with the iron status of those with and without thalassemia. Methods: We performed a cross-sectional descriptive study of infants attending the Well Baby Clinic at Thammasat University Hospital for routine checkups. Complete blood count, hemoglobin electrophoresis, iron parameters, and molecular genetics for common a- and b-thalassemia were evaluated. Results: Overall, 97 of 206 (47%) participants had thalassemia minor, the majority having Hb E traits. None had thalassemia intermedia or major. Familial history of anemia or thalassemia presented an increased risk of detecting thalassemia minor in offspring (OR 5.18; 95% CI 2.60-10.33, p=0.001). There were no statistical differences in transferrin saturation, serum ferritin and hepcidin between iron-replete infants with thalassemia minor and those without. However, one-third of infants with thalassemia minor (31/97) also had iron deficiency anemia (IDA), with a similar risk of having iron deficiency to infants without thalassemia. There was no hepcidin suppression in our infants with thalassemia minor as compared to controls. Conclusions: Both thalassemia and IDA are endemic to Southeast Asia. Infants with thalassemia minor, particularly with Hb E and a-thalassemia traits, are at risk of IDA. Our short-term universal iron supplementation program for 6 to 12-month old infants does not appear to increase the risk of those with thalassemia minor developing iron overload in the future.

IntroductionThe number of pediatric COVID-19 infections is increasing; however, the data on long COVID conditions in children is still limited. Our study aimed to find the prevalence of long COVID in children during the Delta and Omicron waves, as well as associated factors.MethodsA single-center prospective cohort study was conducted. We included 802 RT-PCR-confirmed COVID-19 pediatric patients in the Delta and Omicron periods. Long COVID was defined as having symptoms for ≥3 months after infection. Parents and/or patients were interviewed by phone. Multivariable logistic regression was performed to find associated factors with long COVID.ResultsThe overall prevalence of long COVID was 30.2%. The Delta period had more prevalence than the Omicron (36.3% vs. 23.9%). Common symptoms for patients 0–3 years’ old were loss of appetite, rhinorrhea, and nasal congestion. Conversely, patients 3–18 years’ old had hair loss, dyspnea on exertion, rhinorrhea, and nasal congestion. However, there was no significant negative impact on daily life. Most symptoms improved after a 6-month follow-up. Factors associated with long COVID-19 conditions were infection during the Omicron period (adjusted OR: 0.54; 95% CI: 0.39–0.74, P

Background and objectivesThe study of prevalence, risk factors, and vaccine effectiveness (VE) in children, adolescents, and young adults during the Omicron era has been limited, making this the objectives of the study.MethodsA prospective, test-negative case-control study was conducted on patients aged 0–24 years old classified as patients under investigation (PUI) from January to May 2022. PUI with positive RT-PCR within 14 days were classified as cases, whilst PUI with negative RT-PCR in 14 days were controls. Univariate and multivariate analyses determined risk factors; VE was calculated using [1-adjusted odds ratio (OR)] × 100.ResultsThe final analyses included 3,490 patients with a PUI infection rate of 45.6%. Heterologous vaccination regimens, including inactivated vaccines, viral vectors, and mRNA were utilized during the study period. A total of 2,563 patients (73.5%) had received at least 2 vaccine doses, regardless of regimen. Male gender and household infections were independent risk factors for the development of infection, with an adjusted OR of 1.55 and 1.45, respectively. Underlying comorbidities and obesity were not significantly associated with the development of infection. Patients with underlying comorbidities were more likely to have at least moderate severity of infection with the adjusted OR of 3.07. Age older than 11 years was associated with lower infection risk and development of at least moderate infection with adjusted OR of 0.4 and 0.34, respectively. Vaccinated participants also had a lower risk of developing at least moderate infection: adjusted OR of 0.40. The adjusted VE of any vaccination regimen for infection prevention for one, two, three, or more than four doses was 21.8%, 30.6%, 53.5%, and 81.2%, respectively. The adjusted VE of any vaccination regimen for prevention of at least moderate severity of the disease for one, two, three, or more than four doses was 5.7%, 24.3% 62.9%, and 90.6%, respectively.ConclusionDisease prevalence among PUI was substantially high during the Omicron wave. A two-dose vaccination regimen does not appear sufficient to ensure protection against infection.

Background: 6-Mercaptopurine (6-MP), a thiopurine agent, is an indispensable medication for treating pediatric acute lymphoblastic leukemia (ALL). However, its side effects of neutropenia and hepatotoxicity might interrupt treatment, resulting in poor outcomes. Inosine triphosphate pyrophosphatase (ITPA), an enzyme in the thiopurine pathway, may prevent the accumulation of toxic thiopurine metabolites. Studies on ITPA and thiopurine-associated toxicities are scarce. Methods: This study retrospectively investigated 1- to 15-year-old children with ALL who received 6-MP during the maintenance phase of treatment between 2000 and 2020. Toxicity during the first year of maintenance therapy and the mean dose of 6-MP were analyzed. Results: The 209 patients had a median age of 4.8 (0.3-14.8) years. Of these, 124 patients (59.3%) had wildtype ITPA, 73 patients (34.9%) had heterozygous ITPA 94C>A (hetITPA), and 12 patients (5.7%) had homozygous ITPA 94C>A (homITPA), with an allele frequency of 0.23. The incidence of neutropenia among ITPA polymorphisms did not significantly differ (P = 0.813). In patients harboring homITPA, transaminitis was more frequent than other polymorphisms but without a significant difference (P = 0.063). The mean dose of 6-MP for patients with homITPA was significantly lower than that for patients with hetITPA or wildtype ITPA (P = 0.016). Conclusions: HomITPA had a higher incidence of transaminitis and required a significantly larger dose reduction of 6-MP than wildtype ITPA. Further study is warranted to elucidate the effects of ITPA polymorphisms on toxicity in patients with ALL treated with 6-MP.

Background: Several disseminated intravascular coagulation (DIC) scoring systems are used for prognosticating the clinical outcomes of patients with DIC. However, research on children is scarce. This study compared the clinical outcomes of overt and non-overt DIC using the International Society on Thrombosis and Hemostasis (ISTH) DIC scoring system. Methods: This retrospective study reviewed data on children aged 1 month to 15 years diagnosed with DIC between 2003 and 2014. Results: Of 244 patients, 179 (73.4%) had overt DIC, and 65 (26.6%) had non-overt DIC. The most common causes were infection (84.8%), tissue injury (7%), and malignancies (2.9%). The 28-day case fatality rate was significantly higher for overt than non-overt DIC (76% vs 15.6%; P

Background: Few studies had focused on the epidemiological and clinical characteristics of pediatric COVID-19 (SARS-CoV-2) during Delta and pre-Delta eras in Asia, despite it being a pandemic. Objective: To study the epidemiological and clinical characteristics of three waves of pediatric COVID-19 infections in a tertiary-care setting in Thailand. Methods: This retrospective study reviewed all PCR-confirmed pediatric (0-18 years of age) COVID-19 infections between January 13th, 2020 and October 31st, 2021, in a tertiary care system, Thailand. Results: There were 1,019 patients, aged 0.02 - 18 years, median age of 9.2 years, with no gender differences. Asymptomatic cases accounted for 35.7%, of which 18.9% had abnormal chest X-ray findings. The majority of cases were classified as having mild clinical symptoms, with only 0.8 and 0.4% developing severe and critical illness, respectively. There were no deaths. The Delta dominant group appeared more transmissible, but we did not see any difference in disease severity. Upper respiratory tract symptoms were predominant, while few cases had lower respiratory signs. The sensitivity and specificity of dyspnea symptoms to predict pneumonia (abnormal chest X-ray) were 14% and 95%, respectively, with a likelihood ratio 3.37. The overall prognosis was good, with only 0.01 % needing respiratory equipment. All cases showed clinical improvement with a decent recovery. Conclusion: Pediatric COVID-19 during Delta era appeared generally more transmissible but benign. One-fifth of cases had pneumonia, but few cases needed respiratory support. Prevention remains important for disease control. Keywords: Pediatric, COVID-19, SARS-CoV-2, Delta, Epidemiology

Background There were limited epidemiological data of pediatric COVID-19 in Asia outside China, especially during the era of the variants of concern such as the Delta and Alpha variants. The objective was to describe the clinical epidemiology of pediatric COVID-19 in a tertiary care center in Thailand from April to August 2021. The identification of risk factors for the development of pneumonia in these children was also performed. Methods This retrospective cohort study was conducted by retrospective chart review of all children aged 0–15 years admitted to Thammasat University Hospital care system during the study period. The risk factors for the development of pneumonia were analyzed using logistic regression. Results A total of 698 children were included for analysis, of which 52% were male. The mean age of the cohort was 7.2 + 4.5 years old. Radiographic pneumonia was identified in 100 children (14.3%) and a total of 16 children (2.3%) were diagnosed with severe and critical diseases. The mortality rate was 0.1%. Children younger than 1 year and children with comorbidity were at higher risk of developing pneumonia (Adjusted odds ratios 2.99 (95% confidence interval (CI): 1.56–5.74) and 2.32 (95% CI: 1.15–4.67), respectively). Conclusion In the era of the variants of concern, the proportion of children with severe and critical diseases remained low. However, prudence must be taken in caring for younger children and children with comorbidity.

Although the outcome of childhood leukemia and severe aplastic anemia (SAA) has improved, infectious complications are still the major concern, particularly invasive fungal infection (IFI), which is one of the most common causes of infectious related death in such patients with prolonged neutropenia. A retrospective study of IFI in pediatric patients with newly diagnosed and relapsed acute leukemia and SAA in Siriraj Hospital, Mahidol University, Thailand, was conducted. There were 241 patients (150 patients with ALL, 35 patients with AML, 31 patients with relapsed leukemia and 25 patients with SAA) with the median age of 5.4 years (rage, 0.3-16.0 years). The overall prevalence of IFI was 23.2%, and the breakdown prevalence in ALL, AML, relapsed leukemia and SAA were 12.7%, 37.1%, 45.2% and 40.0% respectively. Candida tropicalis was the most common identifiable organism. Pulmonary IFI caused by invasive aspergillosis was the most common site of infection. The overall case-fatality rate was 50.0% with the highest rate in relapsed leukemia of 92.9%. In multivariable analysis, the age > 4 years, AML, relapsed leukemia and SAA were found to be independent risk factors of IFI with adjusted odds ratio of 2.3, 4.1, 5.1 and 3.7 respectively. In SAA group, only very severe aplastic anemia (ANC < 200 mm3) was found to be associated with development of IFI with odds ratio of 32.7. IFI in Thai children with hematologic diseases appeared to be prevalent with high fatality. Anti-fungal prophylaxis should be considered in patients with SAA to prevent IFI.

Background: Thalassemia remains a chronic challenging disease in Thailand, but national prenatal screening along with better treatment and management may have improved health-related quality of life (HRQoL) for pediatric patients. We aimed to measure the HRQoL of transfusion dependent (TDT) and non-transfusion dependent (NTDT) of these pediatric patients at our institute. Methods: We included all patients 2 – 18 years old, with TDT and NTDT, using the Pediatric Quality of Life Inventory 4.0 Generic Core Scales (PedsQL) and the EuroQol Group’s Five Dimensions for Youth (EQ-5D-Y) instruments. Patients and caregivers responded as appropriate for age. Results: Mean PedsQL total summary scores (TSS) (SD) of child self-reports and parent proxy-reports were 81.00 (10.94) and 78.84 (16.72) from 150 participants. Mean EQ-5D-Y VAS (SD) for children was 89.27 (11.56) and 86.72 (10.62) for parent proxies. The most problematic EQ-5D-Y dimension was “having pain or discomfort”. These scores had significant correlations between child and parental proxy perspectives, as well as between the PedsQL and EQ-5D-Y. An age of 8 - 12 years and oral chelation therapy predicted lower self-reported PedsQL TSS. Parental proxy-report predictors for reduced PedsQL TSS and EQ-5D-Y VAS were primary school education for children, parental proxy secondary school education, Universal Coverage insurance, and TDT. Conclusion: HRQoL scores of our pediatric thalassemia patients had improved from the previous decade, and these findings may represent our better standard of care. Some sociodemographic and clinical characteristics may present negative impacts on HRQoL.

Although the outcomes of childhood leukemia and severe aplastic anemia (SAA) have improved, infectious complications are still the major concern. Particularly worrisome are invasive fungal diseases (IFDs), one of the most common causes of infectious-related deaths in patients with prolonged neutropenia. A retrospective study was conducted of IFDs in pediatric patients with newly diagnosed or relapsed acute leukemia, or with SAA, at Siriraj Hospital, Mahidol University, Thailand. There were 241 patients: 150 with acute lymphoblastic leukemia (ALL), 35 with acute myeloid leukemia (AML), 31 with relapsed leukemia, and 25 with SAA. Their median age was 5.4 years (range, 0.3-16.0 years). The overall IFD prevalence was 10.7%, with a breakdown in the ALL, AML, relapsed leukemia, and SAA patients of 8%, 11.4%, 19.3%, and 16%, respectively. Pulmonary IFD caused by invasive aspergillosis was the most common, accounting for 38.5% of all infection sites. Candidemia was present in 34.6% of the IFD patients; Candida tropicalis was the most common organism. The overall case-fatality rate was 38.5%, with the highest rate found in relapsed leukemia (75%). The incidences of IFDs in patients with relapsed leukemia and SAA who received fungal prophylaxis were significantly lower than in those who did not (P = N/A and 0.04, respectively). IFDs in Thai children with hematological diseases appeared to be prevalent, with a high fatality rate. The usage of antifungal prophylaxes should be considered for patients with SAA to prevent IFDs. [ABSTRACT FROM AUTHOR]