Effectiveness of mRNA COVID-19 vaccines against symptomatic SARS-CoV-2 infections during the Delta variant epidemic in Japan: Vaccine Effectiveness Real-time Surveillance for SARS-CoV-2 (VERSUS)

BackgroundAlthough high vaccine effectiveness of messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccines was reported in studies in several countries, data is limited from Asian countries, especially against the Delta (B.1.617.2) variant. MethodsWe conducted a multicenter test-negative case-control study in patients aged [≥]16 visiting hospitals or clinics with signs or symptoms consistent with COVID-19 from July 1 to September 30, 2021, when the Delta variant was dominant ([≥]90% of severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] infections) nationwide in Japan. Vaccine effectiveness of BNT162b2 or mRNA-1273 against symptomatic SARS-CoV-2 infections was evaluated. Waning immunity among patients aged 16 to 64 was also assessed. ResultsWe enrolled 1936 patients, including 396 test-positive cases and 1540 test-negative controls for SARS-CoV-2. The median age was 49 years, 53.4% were male, and 34.0% had underlying medical conditions. Full vaccination (receiving two doses [≥]14 days before symptom onset) was received by 6.6% of cases and 38.8% of controls. Vaccine effectiveness of full vaccination against symptomatic SARS-CoV-2 infections was 88.7% (95% confidence interval [CI], 78.8-93.9) among patients aged 16 to 64 and 90.3% (95% CI, 73.6-96.4) among patients aged [≥]65. Among patients aged 16 to 64, vaccine effectiveness within one to three months after full vaccination was 91.8% (95% CI, 80.3-96.6), and was 86.4% (95% CI, 56.9-95.7) within four to six months. ConclusionsmRNA COVID-19 vaccines had high effectiveness against symptomatic SARS-CoV-2 infections in Japan during July 1 to September 30, 2021, when the Delta variant was dominant nationwide.

Real-world clinical outcomes of treatment with casirivimab-imdevimab among patients with mild-to-moderate coronavirus disease 2019 during the Delta variant pandemic

BackgroundMutations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may reduce the efficacy of neutralizing monoclonal antibody therapy against coronavirus disease 2019 (COVID-19). We here evaluated the efficacy of casirivimab-imdevimab in patients with mild-to-moderate COVID-19 during the Delta variant surge in Fukushima Prefecture, Japan. MethodsWe enrolled 949 patients with mild-to-moderate COVID-19 who were admitted to hospital between July 24, 2021 and September 30, 2021. Clinical deterioration after admission was compared between casirivimab-imdevimab users (n = 314) and non-users (n = 635). ResultsThe casirivimab-imdevimab users were older (P < 0.0001), had higher body temperature ([≥] 38{degrees}C) (P < 0.0001) and greater rates of history of cigarette smoking (P = 0.0068), hypertension (P = 0.0004), obesity (P < 0.0001), and dyslipidemia (P < 0.0001) than the non-users. Multivariate logistic regression analysis demonstrated that receiving casirivimab-imdevimab was an independent factor for preventing deterioration (odds ratio 0.448; 95% confidence interval 0.263-0.763; P = 0.0023). Furthermore, in 222 patients who were selected from each group after matching on the propensity score, deterioration was significantly lower among those receiving casirivimab-imdevimab compared to those not receiving casirivimab-imdevimab (7.66% vs 14.0%; p = 0.021). ConclusionThis real-world study demonstrates that casirivimab-imdevimab contributes to the prevention of deterioration in COVID-19 patients after hospitalization during a Delta variant surge. SummaryThis real-world retrospective study demonstrates the contribution of treatment with casirivimab-imdevimab to the prevention of deterioration in patients with mild-to-moderate coronavirus disease 2019 (COVID-19) even during the Delta variant pandemic.

Development and external validation of the DOAT and DOATS scores: simple decision support tools to identify disease progression among nonelderly patients with mild/moderate COVID-19

BACKGROUNDDue to the dissemination of vaccination against severe acute respiratory syndrome coronavirus 2 in the elderly, the virus-susceptible subjects have shifted to unvaccinated non-elderlies. The risk factors of COVID-19 deterioration in non-elderly patients without respiratory failure have not yet been determined. This study was aimed to create simple predicting method to identify such patients who have high risk for exacerbation. METHODSWe analyzed the data of 1,675 patients aged under 65 years who were admitted to hospitals with mild-to-moderate COVID-19. For validation, 324 similar patients were enrolled. Disease progression was defined as administration of medication, oxygen inhalation and mechanical ventilator starting one day or longer after admission. RESULTSThe patients who exacerbated tended to be older, male, had histories of smoking, and had high body temperatures, lower oxygen saturation, and comorbidities such as diabetes/obesity and hypertension. Stepwise logistic regression analyses revealed that comorbidities of diabetes/obesity, age [≥] 40 years, body temperature [≥] 38{degrees}C, and oxygen saturation < 96% (DOATS) were independent risk factors of worsening COVID-19. As a result two predictive scores were created: DOATS score, which includes all the above risk factors; and DOAT score, which includes all factors except for oxygen saturation. In the original cohort, the areas under the receiver operating characteristic curve of the DOATS and DOAT scores were 0.789 and 0.771, respectively. In the validation, the areas were 0.702 and 0.722, respectively. CONCLUSIONWe established two simple prediction scores that can quickly evaluate the risk of progression of COVID-19 in non-elderly, mild/moderate patients. SummaryThe risk stratification models using independent risks, namely comorbidity of diabetes or obesity, age [≥] 40 years, high body temperature [≥] 38{square}, and oxygen saturation < 96%, DOATS and DOAT scores, predicted worsening COVID-19 in patients with mild-to-moderate cases.