Hybrid immunity from SARS-CoV-2 infection and mRNA BNT162b2 vaccine among Thai school-aged children.

Objective: To compare the immune response of hybrid immunity - arising from SARS-CoV-2 infection and mRNA BNT162b2 vaccination - to that of 2-doses of vaccine. Methods: In a subanalysis of BNT162b2 vaccine trial in 5 to 11-year-old children, There were 179 children who had hybrid immunity compared with 134 children with solely 2-dose vaccine. The immunological outcome was a surrogate virus neutralization test (sVNT) against the Omicron strain, BA.1, (%inhibition). An sVNT level ≥68 % inhibition was considered as protective immune response. Results: From February to April 2022, 179 children had COVID-19 natural infection resulting in hybrid immunity included: Group1;prior vaccination(n = 17), Group2;after the first dose(n = 61), and Group3;after the second dose(n = 97). The proportion of children with protective immune response was higher in Group 3 and Group 1 - 61.9 % and 58.8 %, compared to 36.1 % and 34.3 % in Group 2 and comparator group (2 doses of vaccine), respectively. The geometric mean % inhibition of sVNT was higher in Group 1 (68.5, 95 %CI 55.5-84.6) and Group 3 (63.5, 95 %CI 55.5-72.6), followed by comparator group (49.6, 95 %CI 44.8-54.9) and Group 2 (42.1, 95 %CI 34.6-51.3), p < 0.001. Conclusions: Immune response that arises from BNT162b2 vaccine after natural infection and infection after 2 doses of BNT162b2 was higher than infection after partially-vaccinated children.

Cost-effectiveness of inactivated seasonal influenza vaccination in a cohort of Thai children ≤60 months of age.

BACKGROUND: Vaccination is the best measure to prevent influenza. We conducted a cost-effectiveness evaluation of trivalent inactivated seasonal influenza vaccination, compared to no vaccination, in children ≤60 months of age participating in a prospective cohort study in Bangkok, Thailand. METHODS: A static decision tree model was constructed to simulate the population of children in the cohort. Proportions of children with laboratory-confirmed influenza were derived from children followed weekly. The societal perspective and one-year analytic horizon were used for each influenza season; the model was repeated for three influenza seasons (2012-2014). Direct and indirect costs associated with influenza illness were collected and summed. Cost of the trivalent inactivated seasonal influenza vaccine (IIV3) including promotion, administration, and supervision cost was added for children who were vaccinated. Quality-adjusted life years (QALY), derived from literature, were used to quantify health outcomes. The incremental cost-effectiveness ratio (ICER) was calculated as the difference in the expected total costs between the vaccinated and unvaccinated groups divided by the difference in QALYs for both groups. RESULTS: Compared to no vaccination, IIV3 vaccination among children ≤60 months in our cohort was not cost-effective in the introductory year (2012 season; 24,450 USD/QALY gained), highly cost-effective in the 2013 season (554 USD/QALY gained), and cost-effective in the 2014 season (16,200 USD/QALY gained). CONCLUSION: The cost-effectiveness of IIV3 vaccination among children participating in the cohort study varied by influenza season, with vaccine cost and proportion of high-risk children demonstrating the greatest influence in sensitivity analyses. Vaccinating children against influenza can be economically favorable depending on the maturity of the program, influenza vaccine performance, and target population.

Treatment Outcomes of the Uncomplicated Upper Respiratory Tract Infection and Acute Diarrhea in Preschool Children Comparing Those with and without Antibiotic Prescription.

BACKGROUND: Upper respiratory tract infection (URI) and acute diarrhea are the two most common reasons for ambulatory visits among young children. Unnecessary use of antibiotics to treat such conditions pose significant financial burden and can result in untoward side effects as well as risk of antimicrobial resistance. On the other hand, inadequate antibiotic treatment in certain cases may increase the risk of suppurative complications and/or invasive infection in this population. OBJECTIVE: To compare the treatment outcomes between those with and without antibiotic treatment for the uncomplicated upper respiratory tract infection and acute diarrhea in young children. MATERIAL AND METHOD: A prospective observational study was conducted in two groups of previously healthy children presenting with acute uncomplicated URI (aged 2 to 5 years) or acute diarrhea (aged 6 months to 5 years). On initial enrolment date, patients were treated by a pediatrician who was not a member of the study investigators. The decision for antibiotic prescription was based entirely on attending physicians' discretion. Data regarding clinical presentations, diagnosis, treatment options, and reasons for antibiotic prescription (if any) were collected. Follow-up phone interviews were conducted on day 3 of enrolment to evaluate treatment outcomes. RESULTS: Two hundred nine cases with symptoms compatible with acute URI, and/or 199 cases with acute diarrhea were enrolled between August and November 2013. Antibiotic prescription rates for URI and diarrhea groups were 30.2% and 13.6%, respectively. Among children presenting with URI symptoms, 80.4% (n = 168) were classified as having upper respiratory tract infection e.g., common cold, acute sinusitis, pharyngitis whereas the other 19.6% were diagnosed with other conditions e.g., lower respiratory tract infection, pneumonia, viral exanthema after evaluation by a pediatrician. Overall improvement rates on day 3 were 92.3% and 86.9%for uncomplicated URIand diarrhea group, respectively. Among URI group, parental satisfaction rates were 100% and 96.6% in those received and did not receive antibiotic, respectively (p = 0.188), whereas in the diarrhea group, there were 100% and 92.7, (p = 0.35), respectively. Univariate analyses indicated that the crude odds ratios (OR) and 95% confidence intervals (CI) of treatment failure comparing those with and without antibiotics were 0.5 (0.2, 1.7) and 1.5 (0.6, 3.7) for URI and diarrhea, respectively. Logistic regression analyses indicated that antibiotic treatment was not significantly associated with better treatment outcomes for both URI and diarrhea cases i.e., adjusted ORs and 95% CI of antibiotic for requirement of additional treatment were 1.06 (0.14, 8.15) for URI cases. Further adjusted OR and 95% CI of antibiotic for treatment failure was 0.8 (0.2, 2.9) for acute diarrhea cases. CONCLUSION: Antibiotic did not appear to provide clinical benefit in the management of uncomplicated URI and/or acute diarrhea among previously healthy young children.

Risk factors and outcomes of influenza infection among children presenting with influenza-like illness.

OBJECTIVE: Limited data were available to guide management, counseling, and/or diagnostic investigation among children presenting with influenza-like illness (ILI). During a recent period of high influenza activity, we wished to determine the frequency, outcomes, and factors associated with influenza infection among children presenting with ILI. MATERIAL AND METHOD: During September and October 2010, children presenting with ILI were enrolled. Nasal swabs were sent for polymerase chain reaction (PCR) to determine the frequency and types of influenza. Information of demographic characteristics, potential risk factors, and short-term outcomes of study participants were collected. RESULTS: Among 300 enrolled subjects, influenza infections were identified in 170 (56.7%) cases; 45.7% (n = 137) were influenza A and 11% (n = 33) were influenza B. Most cases recovered uneventfully with a 3.7% (n = 11) hospitalization rate. Risks for hospitalization did not differ by infection status (2.4% vs. 5.4% between those with and without influenza infection, respectively) or types of influenza infection. Logistic regression analysis indicated that older age, having a household member with acute respiratory illness (ARI) during the previous 7 days, having an underlying co-morbidity, and a history of premature birth were associated with influenza, with adjusted odds ratios and 95% confidence intervals of 1.19 (1.087, 1.30), 3.21 (1.096, 9.424), 2.15 (1.244, 3.728), and 0.08 (0.007, 0.876), respectively. CONCLUSION: The outcomes of influenza-associated ILI were generally favourable, with no fatalities and 2.4% risk for hospitalization. Among children presenting with ILI, age, household contact with ARI, and co morbidities increased the likelihood of influenza, whereas history of premature birth was negatively associated with influenza.

Clinical characteristics and cost of chickenpox hospitalization in Thai children.

BACKGROUND: Although primary Varicella-Zoster-Virus (VZV) infection generally causes uncomplicated illness confined to skin and mucous membrane among healthy children, it infrequently causes life-threatening infection especially among immuno-suppressed hosts or young infants. Limited information is available regarding the clinical features, outcomes, and the financial burden incurred by severe primary varicella infection in Thai children who required hospitalization. OBJECTIVE: To determine clinical characteristics particularly the disease severity, prevalence of complication, case fatality rate, and use of healthcare resources in terms of length of stay as well as direct medical cost of varicella-associated hospitalization in children. MATERIAL AND METHOD: A retrospective descriptive study was conducted among children aged one month to 18 years who were hospitalized with chickenpox between 2007 and 2011 at the Queen Sirikit National Institute of Child Health, Bangkok, Thailand. Information on clinical manifestations, complications, and outcomes were obtained by medical record abstraction, and data on hospital charges were obtained from the hospital financial database. RESULTS: A total of 101 cases of chickenpox were identified, with a median (interquartile range IQR) age of 4 (0.8, 7.25) years. Underlying predisposing conditions for severe varicella infection were identified in 35 cases (34.7%). Seventy four of 101 (73.3%) patients developed complications, with skin and soft tissue infections being the most common (50.5%), followed by pneumonia (12.7%) and neurological complications (6.4%). There were no fatal cases. Median (IQR) duration of hospitalization and hospital charges were 6 (3, 9) days and US$ 330.2 ($139.3, $1,013.5), respectively. Children with predisposing conditions for severe varicella were significantly older, incurring 6-fold higher hospital charges and 2-fold longer hospitalization compared to their counterparts. CONCLUSION: The high rate of complicated varicella and financial burden reported in this study suggested that the severity of varicella complications in children might have been previously underestimated. This study provides relevant information regarding the burden of hospitalized varicella infection among both otherwise healthy children as well as children with predisposing immuno-suppression.

Clinical characteristics and hospital charges among Thai children hospitalized with influenza.

Infants and young children are at high risk for influenza-associated morbidity, mortality, and the need for hospitalization. Only limited information is available regarding the clinical findings, outcomes, and financial burden incurred by Thai children hospitalized with severe influenza, therefore, we examined these areas in this retrospective study. The children were diagnosed with having influenza by either a real-time reverse transcriptase-polymerase chain reaction or rapid testing. Two hundred eighty-nine influenza cases hospitalized at the Queen Sirikit National Institute of Child Health, Bangkok, Thailand were reviewed. Influenza A, B, and mixed A/B infections were identified in 204 (70.6%), 79 (27.3%), and 6 cases (2.1%), respectively. Children aged younger than 5 years comprised the greatest proportion of cases (60.9%). Fever was the most common symptom (100%), followed by cough (90.3%) and rhinorrhea (70.6%). Diarrhea and thrombocytopenia were found in 22% and 10.4%, respectively. Most cases recovered uneventfully but 2 patients died (fatality rate =0.7%). The median (IQR) duration of hospitalization were 3 (3) days. The median hospital charge was USD169.4 (177.6). Being younger than 2 years old, having predisposing comorbidities, and/or receiving oseltamivir treatment were significantly associated with longer hospitalization; the latter two were associated with higher hospital charges. On logistic regression analyses, being younger than 2 years old was an independent risk factor for disease severity. Most children hospitalized with pediatric influenza had an uncomplicated clinical course. Young children and those with predisposing co-morbidities are at increased risk for extended hospitalization and higher treatment costs.

Therapeutic effectiveness of the generic preparation of meropenem (Mapenem) in the treatment of moderate to severe infection in children.

OBJECTIVE: To compare treatment effectiveness and tolerability between generic meropenem (Mapenem, Siam Pharmaceutical) and the original formulation. MATERIAL AND METHOD: A retrospective review using historical control of children hospitalized at Queen Sirikit National Institute of Child Health was conducted. The demographics, clinical, and treatment outcomes of 180 children receiving generic meropenem were compared with that of 180 children receiving original meropenem. RESULTS: Baseline demographics, clinical characteristics were comparable between both groups. The treatment outcomes on day 3, 7, and 14 of treatment were comparable between the two groups with overall improvement rates of 73.9% and 71.7% for generic and original meropenem, respectively (absolute difference: 2.2%, 95% CI: -6.9%, 11.4%). Both drugs were well tolerated, with only 1.6% of patients in each group who experienced adverse reactions. CONCLUSION: Mapenem exhibited comparable therapeutic effectiveness and tolerability with that of the brand-name formulation in the treatment of moderate to severe infections in a pediatric population.

In vitro activities of colistin and ampicillin/sulbactam against Acinetobacter baumannii.

OBJECTIVE: The aim of the present study was to examine the in vitro antimicrobial activity of colistin, and ampicillin/sulbactam against A. baumannii isolated from pediatric patients and to compare the susceptibility testing using disc diffusion with minimal inhibitory concentration (MIC) E-test method. MATERIAL AND METHOD: One hundred strains of A. baumannii from various clinical isolates were included in the present study. Antimicrobial susceptibilities of A. baumannii to colistin, ampicillin/sulbactam were determined by disc diffusion and minimal inhibitory concentration (MIC) using E-test method. The analysis was stratified by carbapenem resistance status. Sensitivity and specificity of the disc diffusion test compared to the MIC E-test were estimated. RESULTS: Ninety-seven strains of all isolates (97%) were sensitive to colistin using both disc diffusion and E-test methods. In contrast, 41% and 34% of the isolates were sensitive to ampicillin/sulbactam by disc diffusion and MICE-test, respectively. The colistin MIC50 and MIC90 for A. baumannii were 0.38 and 1 microg/mL, respectively. The ampicillin/sulbactam MIC50 and MIC90 were 16 and 89.6 microg/mL, respectively. Based on the results of MIC E-test, ninety-eight (n = 49) and six (n = 3) percent of carbapenem-resistant A. baumannii (n = 50) were susceptible to colistin and ampicillin/sulbactam, respectively. Sensitivity and specificity of disc diffusion test compared to MIC E-test were 99% and 66.7% for colistin and 80.5% and 98.3% for ampicillin/sulbactam, respectively. CONCLUSION: The antimicrobial activities of colistin against A. baumannii isolates remained high for both cabapenem-susceptible and -resistant strains. However, the in vitro activity of ampicillin/sulbactam against A. baumannii was low. Thus, a combination, rather than monotherapy, of ampicillin/sulbactam with other antibiotics is strongly recommended when dealing with A. baumannii infection. In addition, disc diffusion test appeared to be a useful screening method for susceptibility testing for colistin and ampicillin/sulbactam against A. baumanii.