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BackgroundImmunogenicity of inactivated SARS-CoV-2 vaccine has waning antibody over time. With the emergence of the SARS-CoV-2 delta variant, which requires higher neutralizing antibody to prevent infection, a booster dose is needed. ObjectiveTo evaluate immunogenicity and reactogenicity of standard- versus low-dose ChAdOx1 nCoV-19 vaccine booster after CoronaVac in healthy adults. MethodsA double-blinded, randomized, controlled trial of adult, aged 18-59 years, with completion of 2-dose CoronaVac at 21-28 days apart for more than 2 months was conducted. Participants were randomized to receive AZD1222 (Oxford/AstraZeneca) intramuscularly; standard dose (SD, 5x1010 viral particles) or low dose (LD, 2.5x1010 viral particles). Surrogate virus neutralization test (sVNT) against wild type and delta variant, and anti-spike-receptor-binding-domain IgG (anti-S-RBD IgG) were compared as geometric mean ratio (GMR) at day 14 and 90 between LD and SD arms. ResultsFrom July-August 2021, 422 adults with median age of 44 (IQR 36-51) years were enrolled. The median interval from CoronaVac to AZD1222 booster was 77 (IQR 64-95) days. At baseline, geometric means (GMs) of sVNT against delta variant and anti-S-RBD IgG were 18.1%inhibition (95%CI 16.4-20.0) and 111.5 (105.1-118.3) BAU/ml. GMs of sVNT against delta variant and anti-S-RBD IgG in SD were 95.6%inhibition (95%CI 94.3-97.0) and 1975.1 (1841.7-2118.2) BAU/ml at day 14, and 89.4%inhibition (86.4-92.4) and 938.6 (859.9-1024.4) BAU/ml at day 90, respectively. GMRs of sVNT against delta variant and anti-S-RBD IgG in LD compared to SD were 1.00 (95%CI 0.98-1.02) and 0.84 (0.76-0.93) at day 14, and 0.98 (0.94-1.03) and 0.89 (0.79-1.00) at day 90, respectively. LD recipients had significantly lower rate of fever (6.8%vs25.0%) and myalgia (51.9%vs70.7%) compared to SD. ConclusionHalf-dose AZD1222 booster after 2-dose inactivated SARS-CoV-2 vaccination had non-inferior immunogenicity, yet lower systemic reactogenicity. Fractional low-dose AZD1222 booster should be considered especially in resource-constrained settings. Highlights- Low dose AZD1222 could boost comparable immunity to standard dose in healthy adult who completed 2 doses of inactivated SARS-CoV-2 vaccines. - Less reactogenicity occurred in low-dose AZD1222 booster than standard-dose recipients. Thai Clinical Trials Registry (thaiclinicaltrials.org): TCTR20210722003
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OBJECTIVES: Cefditoren pivoxil (CDT) has been used in the treatment of rhinosinusitis. However, little is known about the efficacy of this drug at low and high doses. This study was to compare the efficacy and safety of low dose (8-12 mg/kg/day) and high dose (16-20 mg/kg/day) CDT in the treatment of children with uncomplicated acute rhinosinusitis (ARS). METHODS: This investigation was a randomized, investigator-blinded, and parallel study, conducted in patients (aged 1-15 years) with a clinical diagnosis of uncomplicated ARS. Two groups of patients randomly received low dose or high dose CDT for 14 days. Patients' symptoms were assessed quantitatively using a quantitative symptom score (the S5 score). The changes in sinus symptoms and adverse events were provided by patients and their parents/caregivers. The response rate and adverse effects were evaluated at days 7 and 14. The relapse rate was recorded at days 21 and 28. The recurrences of sinus symptoms at day 60 were also assessed. RESULTS: One hundred forty patients were recruited and randomized; 72 received low dose CDT (group I) and 68 received high dose CDT (group II). There were no significant differences in demographic data including sex, age, presenting symptoms, medical history, and X-ray findings between two groups. The responses rate at day 14 in groups I and II were 95.5% and 95.4%, respectively (P>0.99). There were no significant differences between groups in relapse rate at day 28 and no recurrence at day 60 in either group. The most common treatment-related adverse events were diarrhea (4.2% in group I vs. 2.9% in group II) and vomiting (2.8% in group I vs. 10.3% in group II). There was no statistically significant difference in adverse events between groups. CONCLUSION: Both low and high doses regimens of CDT appeared a similar clinical outcome for treatment in uncomplicated ARS in pediatric patients.
