Molecular characteristics of hereditary red blood cell membrane disorders in Thailand: a multi-center registry.

Red blood cell (RBC) membrane disorders represent a significant category of hereditary hemolytic anemia; however, information from Southeast Asia is limited. We established a national registry aiming to characterize RBC membrane disorders and their molecular features in Thailand. A total of 100 patients (99 kindreds) diagnosed with RBC membrane disorders between 2011 and 2020 from seven university hospitals were enrolled. The most prevalent disorders observed were hereditary elliptocytosis (HE; n=33), hereditary pyropoikilocytosis (HPP; n=28), hereditary spherocytosis (HS; n=19), Southeast Asian ovalocytosis (SAO; n=10 of 9 kindreds), and two cases of homozygous SAO. The remaining cases were grouped as unclassified membrane disorder. Seventy-six patients (76%) were molecularly confirmed by PCR, direct DNA sequencing, or hi-throughput sequencing. The primary causative gene for HE and HPP was SPTB, accounting for 28 out of 29 studied alleles for HE and 56 of 56 studied alleles for HPP. In the case of HS, dominant sporadic mutations in the ANK1 gene (n=4) and SPTB gene (n=3) were identified as the underlying cause. Notably, the four most common variants causing HE and HPP were SPTB Providence (c.6055 T>C), SPTB Buffalo (c.6074 T>G), SPTB Chiang Mai (c.6224 A>G), and SPTB c.6171__82delins TGCCCAGCT. These recurrent SPTB mutations accounted for 79 out of 84 mutated SPTB alleles (94%). In summary, HE and hereditary HPP associated with recurrent SPTB mutations are the predominant types of RBC membrane disorders observed in Thailand. These findings have significant implications for the clinical management and future research of RBC membrane disorders in the region.

Enhancing outcomes of childhood acute lymphoblastic leukemia in workplace diversity in Thailand: multicenter study on behalf of the Thai Pediatric Oncology Group.

The Thai Pediatric Oncology Group (ThaiPOG) has adapted treatment regimens from the Children's Oncology Group (COG) to enhance outcomes for childhood acute lymphoblastic leukemia (ALL). This study examined the risk factors and treatment results of pediatric ALL in Thailand. This multicenter study included newly diagnosed children (< 18 years) with ALL in 19 centers between January 1, 2015, and December 31, 2019. Most of the 1,157 patients (97.6%) were treated according to ThaiPOG protocols. The genetic testing was performed in 71% of patients. The patients were classified as standard (n = 539), high (n = 402), and very high (n = 130) risks. The 5-year event-free survival (EFS) and overall survival (OS) rates were 75% (95% confidence intervals (CI), 72%-77.8%) and 81.7% (95% CI, 78.9%-84.1%), respectively. The 5-year EFS rates of the standard-, high-, and very high-risk groups were 78.5% (95% CI, 74.1%-82.3%), 73.6% (95% CI, 68.5%-78%) (p = 0.761), and 65% (95% CI, 55.1%-73.3%) (p = 0.001), respectively, and the 5-year OS rates were 86.9% (95% CI, 83.1%-89.9%), 77.3% (95% CI, 72.5%-81.4%) (p = 0.001), and 73.1% (95% CI, 63.7%-80.4%) (p = 0.001), respectively. The independent risk factors for relapse and death were age ≥ 10 years, white blood cells (WBCs) ≥ 50,000/mm3, M2 or M3 marrow status at the end of induction, and high-risk group. The overall outcome of Thai pediatric ALL has improved after the implementation of new modified COG treatment protocols. High-risk characteristics of ALL increased adverse outcome risk.

Comparative Study of Acute Anogenital Injury Between Consensual and Nonconsensual Postmenarche Adolescents.

ABSTRACT: In Thailand, sexual activity involving those under the legal age of consent may be legally and medically problematic, even if it is consensual. Thus, differentiating anogenital injury characteristics that occur during consensual versus nonconsensual acts with adolescent female subjects could aid legal advocates and improve health care and social support for these patients. Our study included postmenarche female patients having acute anogenital injuries after consensual and nonconsensual penetration. We found that nonconsenting patients had more cases of anogenital injury than consenting (69.8% vs 55.5%), with at least 1 abrasion, contusion, laceration, labia major or minor injury, and external or internal site injury. Both consensual and nonconsensual cases had the same common sites for injury type, reflecting the same injury mechanism; prior sexual intercourse was a significant protective factor against some anogenital injury prevalence, types, and sites for both groups. Adolescents forced into nonconsensual acts had more nonanogenital injuries. Looking at factors such as age, prior sexual activity history, and use of condom and/or contraceptive pills, it is very clear that early sexual education, particularly around consent, is critically needed in Thailand for the best interests of adolescents and children so that they and/or their guardians can access the health and legal resources required.

Associations between the infant and young child feeding index and nutritional status.

BACKGROUND: The infant and child feeding index (ICFI) is a single summary World Health Organization influenced index to assess feeding quality in infants and young children aged 6-36 months. This study aimed to demonstrate any associations between ICFI and nutritional status in a single Thai center. METHODS: The demographic data and feeding practices of healthy infants and children aged 6-36 months were collected from questionnaires given to 304 parents/caregivers; anthropometric measurements were taken. Associations between ICFI and weight-for-age Z scores (WAZ), length/height for age Z scores (LAZ/HAZ), weight-for-length/height Z scores (WLZ/WHZ), and body mass index-for-age Z scores (BAZ) were examined. RESULTS: The mean ICFI was 6.14 ± 1.63 and was lowest in the 6-8 months age group. Breastfed infants had significantly higher ICFI scores than those not breastfed. Factors influencing ICFI were infant age and milk volume intake. The ICFI was negatively associated with WAZ, WLZ/WHZ, and BAZ (ß = -0.13, P = 0.037; ß = -0.17, p = 0.01; ß = -0.15, P = 0.026, respectively). Breastfeeding was also negatively associated with WAZ, LAZ/HAZ, WLZ/WHZ, and BAZ. CONCLUSIONS: This study demonstrated a negative association between the ICFI and nutritional status. Breastfeeding may have obscured some positive effects from appropriate feeding practices, while dairy consumption may have hidden negative outcome from inappropriate ones. Despite the ICFI appearing to reflect infant and young child feeding behaviors, using the ICFI alone may not accurately reveal nutritional status.

Clinical outcomes and prognosis of Thai retinoblastoma patients.

BACKGROUND: Retinoblastoma (RB) outcomes in Thailand are unfavorable compared to those of developed countries. This study aims to determine whether the clinical outcomes of patients with RB significantly improved after the implementation of new therapeutic approaches and which clinical factors affect survival and globe-saving outcomes. METHODS: The medical records of patients newly diagnosed with RB and treated at Siriraj Hospital between January 2005 and December 2018 were reviewed retrospectively. Clinical data, treatments, and outcomes were collected and analyzed. RESULTS: In 194 eyes (144 patients), leukocoria was the most common presenting feature (76.8%); 129 (66.5%) eyes were staged in group E of the International Classification of Intraocular Retinoblastoma. Of the 149 enucleated eyes, 35 had high-risk histopathological features, mostly choroidal invasion; 45 eyes (23.2%) could be salvaged. The 5-year overall survival rate was 90.3%, an improvement compared to the previous study. The 5-year enucleation-free survival rates of Groups A and B, C, D and E were 100%, 83.1%, 36.7% and 16.6% respectively. Factors associated with a lower survival rate were interval from symptom onset to diagnosis >3 months (hazard ratio (HR): 5.8: 95% confidence interval (CI): 1.637, 20.579) and buphthalmos (HR: 12.57: 95% CI: 3.936, 40.153). Factors associated with high-risk features were secondary glaucoma (HR: 11.016: 95% CI: 1.24, 98.10) and pseudohypopyon (HR: 14.110: 95% CI: 2.16, 92.05). CONCLUSIONS: Survival rates and globe-saving rates appear to have improved; however, advanced-stage presentation remains the major hindrance. Further studies with a larger cohort and longer follow-up are warranted.

Predictors of severe adverse outcomes in febrile neutropenia of pediatric oncology patients at a single institute in Thailand.

Febrile neutropenia in pediatric oncology patients may lead to severe infection, with adverse events including septic shock or death. The aim of the study was to investigate the prevalence of severe adverse outcomes and to determine the associated risk factors. This is a retrospective cohort study of pediatric oncology patients with febrile neutropenia from October 2013 to September 2017 at Thammasat University Hospital, Thailand. Clinical assessment and time-to-event of severe outcomes were analyzed. There were 95 febrile neutropenic episodes; severe adverse outcomes were documented in 11 (11.5%), with no infection-associated mortalities. Those with severe outcomes were older, received prophylactic granulocyte-colony stimulating factor (G-CSF), and had documented infection, lower initial ANC, and central venous catheter insertion. The proportional hazard regression model revealed age ≥ 10 years (hazard ratio [HR], 5.96; p = 0.005), prophylactic G-CSF (HR, 4.52; p = 0.028), and microbiologically documented infections (HR, 12.53; p = 0.017) independently predicted severe adverse outcomes. Although severe adverse outcomes occurred in only 11.5% of our febrile neutropenic episodes, we identified a few risk factors that may help predict those at highest risk.

Effect of NUDT15 on incidence of neutropenia in children with acute lymphoblastic leukemia.

BACKGROUND: 6-Mercaptopurine (6-MP) is considered the backbone of therapy in the maintenance phase of acute lymphoblastic leukemia (ALL). Gene polymorphisms involved in thiopurine degradation are predictors of toxicity in patients treated with 6-MP. We investigated the effects of nucleoside diphosphate linked moiety X (nudix) type motif 15 (NUDT15) polymorphism NUDT15c.415C>T on neutropenia incidence, dose adjustment for 6-MP, and survival rates in Thai children with ALL. METHODS: Children diagnosed with ALL who received 6-MP in the maintenance phase of treatment, in 2005-2016, were retrospectively enrolled. RESULTS: The subjects consisted of 102 patients (median age, 5.2 years; 58 boys). On genetic testing 78, 22, and two patients were normal (CC), heterozygous (CT), and homozygous (TT), respectively. The incidence of neutropenia at 3 months was significantly higher in the CT/TT than CC polymorphism groups (OR, 12; 95%CI: 3.781-38.085, P < 0.001). The mean dose of 6-MP at 3, 6, and 12 months was significantly lower in the CT/TT versus the CC group (P < 0.001). The 5 year overall survival (OS) rate for CC was 80.4%, and for CT/TT, 95.5% (P = 0.34). The 5 year event-free survival (EFS) for CC and CT/TT was 75.1% and 85.7%, respectively (P = 0.17). After adjusted risk classification, no significant differences were observed for OS or EFS between the CC and CT/TT groups. CONCLUSION: Patients harboring the CT/TT polymorphism of NUDT15 had a significantly higher incidence of neutropenia during the first 3 months of maintenance, resulting in significantly lower doses of 6-MP.

Infant feeding practices in relation to iron status and other possible nutritional deficiencies in Pathumthani, Thailand.

BACKGROUND AND OBJECTIVES: Iron deficiency (ID) is the most common micronutrient deficiency worldwide and usually leads to impaired neurodevelopment. Appropriate introduction of complementary foods is mandatory for all infants to prevent iron insufficiency. We aimed to demonstrate feeding behaviors in relation to infant iron status and also identify potential concomitant nutrient inadequacies. METHODS AND STUDY DESIGN: A cross-sectional descriptive study of infants 6-12 months old was performed at the Well Baby Clinic at Thammasat University Hospital, Pathumthani. Demographic data, feeding practices and nutritional status were obtained. Dietary intake was evaluated using general and food frequency questionnaires. Blood samples for complete blood count and iron studies were investigated. RESULTS: We enrolled 206 infants (mean age 8.552.1 months). Prevalence of ID and iron deficiency anemia (IDA) was 34.0% and 25.7%, respectively. In multivariable ordinal continuation ratio logistic regression analysis for risk of iron depletion severity among the 3 groups (normal, ID and IDA infants), we found a stepwise increase in odds ratios for iron depletion with lower family income, longer duration of breastfeeding, delayed introduction of meat, and lower dietary iron intake. IDA infants had significantly lower intakes of energy, protein, fat and various micronutrients, compared to those with normal iron status. CONCLUSIONS: Infants with ID may have low intakes of other nutrients due to reduced complementary food intake. Nutritional education for appropriate feeding practices should be provided to prevent ID and other possible micronutrient deficiencies.

Hematologic Malignancies Associated With Mediastinal Germ Cell Tumors: 10 Years' Experience at Thailand's National Pediatric Tertiary Referral Center.

Mediastinal germ cell tumor (MGCT), which accounts for 1% to 3% of extragonadal germ cell tumors, has unique manifestations; it is associated with several types of hematologic malignancy, particularly myeloid neoplasm. The aim of this study was to report the 10-year incidence, clinical characteristics, and outcomes of MGCT at Thailand's national pediatric tertiary referral center. This retrospective study included patients diagnosed with MGCT at the Department of Pediatrics, Siriraj Hospital during 2005 to 2014. Eight patients (all male) were diagnosed with MGCT. Five of 8 patients were found to have hematologic abnormalities. Three patients were diagnosed with acute myeloid leukemia (AML) (one patient with M1, another having M7, and the other with M0). Another patient had mixed MGCT with mediastinal myeloid sarcoma (MMS). The other patient had malignancy-associated hemophagocytic lymphohistiocytosis syndrome (M-HLH). Isochromosome 12p was detected in 3 patients (AML [2], mixed MGCT/MMS [1]). Four of 5 patients with hematologic abnormalities died of hematologic abnormalities or treatment complication (AML [3], M-HLH [1]). One patient with mixed MGCT/MMS survived with chemotherapy. All patients with AML and MMS were nonseminomatous MGCT and the onset of myeloid malignancies were within 1 year after the diagnosis of MGCT. Associated hematologic malignancies should be suspected in MGCT with abnormal blood count or hematologic symptoms. Isochromosome 12p was the most common cytogenetic finding in MGCT-associated myeloid malignancies patients. Those with nonseminomatous MGCT should have their blood count carefully monitored especially during the first year after the diagnosis of MGCT. Better treatment alternatives for MGCT with associated hematologic malignancies are warranted to ameliorate adverse outcomes.

Prevalence and predictors of cardiac and liver iron overload in patients with thalassemia: A multicenter study based on real-world data.

Prevalence of cardiac and liver iron overload in patients with thalassemia in real-world practice may vary among different regions especially in the era of widely-used iron chelation therapy. The aim of this study was to determine the prevalence of cardiac and liver iron overload in and the management patterns of patients with thalassemia in real-world practice in Thailand. We established a multicenter registry for patients with thalassemia who underwent magnetic resonance imaging (MRI) as part of their clinical evaluation. All enrolled patients underwent cardiac and liver MRI for assessment of iron overload. There were a total of 405 patients enrolled in this study. The mean age of patients was 18.8±12.5years and 46.7% were male. Two hundred ninety-six (73.1%) of patients received regular blood transfusion. Prevalence of cardiac iron overload (CIO) and liver iron overload (LIO) was 5.2% and 56.8%, respectively. Independent predictors for iron overload from laboratory information were serum ferritin and transaminase for both CIO and LIO. Serum ferritin can be used as a screening tool to rule-out CIO and to diagnose LIO. Iron chelation therapy was given in 74.6%; 15.3% as a combination therapy.

Justification of Universal Iron Supplementation for Infants 6-12 months in Regions with a High Prevalence of Thalassemia.

Introduction: Many clinicians hesitate to adopt 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 α- and ß-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 α-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.

Prevalence, risk factors, and vaccine effectiveness of COVID-19 infection in thai children, adolescents, and young adults in the omicron era.

Background and objectives: The 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. Methods: A 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. Results: The 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. Conclusion: Disease prevalence among PUI was substantially high during the Omicron wave. A two-dose vaccination regimen does not appear sufficient to ensure protection against infection.

Prevalence and associating factors of long COVID in pediatric patients during the Delta and the Omicron variants.

Introduction: The 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. Methods: A 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. Results: The 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 < 0.001), fever (adjusted OR: 1.49, 95% CI: 1.01-2.20, P = 0.04) and rhinorrhea (adjusted OR: 1.47, 95% CI: 1.06-2.02, P = 0.02). Conclusion: Infection during the Omicron wave has a lower prevalence of long COVID. The prognosis is often favorable, and most symptoms gradually become less. However, pediatricians may schedule appointments to surveil long COVID in children with fever or rhinorrhea as an initial symptom.

Outcomes of Overt and Non-overt Disseminated Intravascular Coagulation Using the ISTH DIC Scoring System in Children: A Single-Center Study.

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. Therefore, 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 one 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 < 0.001). DIC scores were significantly associated with mortality (R2 = 0.89). Each clinical parameter (platelet count, prothrombin time, and fibrin degradation products) was associated with mortality (P = 0.01). On multivariable analysis, the factors associated with death were platelet counts ≤ 50 000 cells/mm3 (OR, 2.42; 95% CI, 1.08-5.42; P = 0.031); overt DIC score (OR, 7.62; 95% CI, 2.94-19.75; P < 0.001); renal dysfunction (OR, 2.92; 95% CI, 1.34-6.37; P = 0.007); shock (OR, 39.62; 95% CI, 4.99-314.84; P = 0.001); and acute respiratory distress syndrome (OR, 25.90; 95% CI, 3.12-214.80; P = 0.003). Conclusions: The 28-day case-fatality rate was significantly higher for patients with overt than non-overt DIC and concordant with ISTH scores. ISTH DIC scores can be used as a clinical predictor for DIC in children.

ITPA Polymorphisms and the Incidence of Toxicities in Children with Acute Lymphoblastic Leukemia.

Background: 6-Mercaptopurine (6-MP), a thiopurine agent, is a essential 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 wild-type 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 wild-type ITPA (P = 0.016). Conclusions: HomITPA had a higher incidence of transaminitis and required a significantly larger dose reduction of 6-MP than wild-type ITPA. Further study is warranted to elucidate the effects of ITPA polymorphisms on toxicity in patients with ALL treated with 6-MP.

Real-life effectiveness of COVID-19 vaccine during the Omicron variant-dominant pandemic: how many booster doses do we need?

The 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.

An epidemiological study of pediatric COVID-19 in the era of the variant of concern.

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.

Comparing real-life effectiveness of various COVID-19 vaccine regimens during the delta variant-dominant pandemic: a test-negative case-control study.

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.

Epidemiological and Clinical Characteristics of Pediatric COVID-19 in the Tertiary Care System in Thailand: Comparative Delta and pre-Delta Era.

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 13, 2020, and October 31, 2021, in a tertiary care system in Thailand. Results: 1,019 patients, aged 0.02 - 18 years, 552 (54.2%) male, and 467 (45.8%) female, with a median age of 9.2 years, were enrolled. Asymptomatic cases accounted for 35.7%, of which 106 (18.9%) had abnormal chest X-ray findings. Most cases were classified as having mild clinical symptoms, with only 8 (0.8%) and 4 (0.4%) developing a severe and critical illness, respectively. There were no deaths. The Delta variant appeared more transmissible than previous ones, but we did not see any difference in disease severity. Upper respiratory tract symptoms were predominant, while few cases had lower respiratory tract involvement. The sensitivity and specificity of dyspnea symptoms to predict radiologically confirmed pneumonia were 14% and 95%, respectively, with a likelihood ratio of 3.37. The overall prognosis was good, with only 13 (1.3 %) needing respiratory support. All cases showed clinical improvement with a decent recovery. Conclusion: Pediatric COVID-19 during the Delta variant predominance era generally appeared more transmissible but benign. One-fifth of cases had pneumonia, but few cases needed respiratory support. Prevention remains important for disease control.