Vaccine effectiveness (VE) and the urgency of booster vaccination against SARS-CoV-2 Omicron variant need evaluation. A systematic search was conducted from 1–6 April, 2022. VE difference (VED) estimates were assessed using random-effects and meta-regression analyses were performed for evaluating VE over time. Compared to full dose, booster dose of overall vaccines provided better protection against any and severe Omicron infections within 3 months (p < 0.001), and within 3 months or more in any, severe, and symptomatic infections (p < 0.001). From meta-regression analysis of overall vaccines, the full-dose VE against any and symptomatic Omicron infections reduced per month by 2.45% and 5.5%, respectively; whereas booster dose effectiveness against any and symptomatic Omicron infections reduced per month by 1.79% and 1.14%, respectively. The VE estimates of booster dose provide excellent protection against symptomatic infection compared to full dose. The VE estimates of Ad26.COV2.S, BNT162b2, ChAdOx1 nCov-19, and mRNA-1273 against Omicron infection are generally moderate, despite the VE estimates declining over time.

Background: Abrupt implementation of lockdowns during the coronavirus disease 2019 (COVID-19) pandemic affected the management of diabetes mellitus in patients worldwide. Limited access to health facilities and lifestyle changes potentially affected metabolic parameters in patients at risk. We conducted a meta-analysis to determine any differences in the control of metabolic parameters in patients with diabetes, before and during lockdown.Methods: We performed searches of five databases. Meta-analyses were carried out using random- or fixed-effect approaches to glycaemic control parameters as the primary outcome: glycosylated hemoglobin (HbA1c), random blood glucose (RBG), fasting blood glucose (FBG), time-in-range (TIR), time-above-range (TAR), time-below-range (TBR). Mean difference (MD), confidence interval (CI), and P value were calculated. Lipid profile was a secondary outcome and is presented as a descriptive analysis.Results: Twenty-one studies enrolling a total of 3,992 patients with type 1 or type 2 diabetes mellitus (T1DM or T2DM) were included in the study. Patients with T1DM showed a significant improvement of TIR and TAR (MD=3.52% [95% CI, 0.29 to 6.74], I2=76%, P=0.03; MD=–3.36% [95% CI, –6.48 to –0.25], I2=75%, P=0.03), while FBG among patients with T2DM significantly worsened (MD=3.47 mg/dL [95% CI, 1.22 to 5.73], I2=0%, P<0.01). No significant difference was found in HbA1c, RBG, and TBR. Use of continuous glucose monitoring in T1DM facilitated good glycaemic control. Significant deterioration of lipid parameters during lockdown, particularly triglyceride, was observed.Conclusion: Implementation of lockdowns during the COVID-19 pandemic did not worsen glycaemic control in patients with diabetes. Other metabolic parameters improved during lockdown, though lipid parameters, particularly triglyceride, worsened.

Wardhana MP, et al. Yonsei Med J. 2024 Apr;65(4):202-209. https://doi.org/10.3349/ymj.2023.0309

Background There is a need for evaluation regarding vaccine effectiveness (VE) and the urgency of booster vaccination against Covid-19 B.1.1.529 (Omicron) variant. Methods Systematic search was conducted on April 6th, 2022, on databases (PubMed, ScienceDirect, CENTRAL, Web of Science, Scopus). VE difference (VED) estimates were assessed using random-effects model and DerSimonian-Laird tau estimators. Two models result, i.e., within 3 months and within 3 months or more, are compared. VE versus time meta-regression analysis was evaluated using mixed-effects model with Restricted-Maximum Likelihood tau estimators and Hartung-Knapp adjustments. Findings Ad26.COV2.S, BNT162b2, ChAdOx1 nCov-19, and mRNA-1273 vaccines were included in the analyses. Compared to full dose, booster dose of overall vaccines provided better protection against any (VED=22% (95%CI 15%-29%), p<0.001), severe (VED=20% (95%CI 8%-32%), p=0.001) and symptomatic (VED=22% (95%CI 11%-34%), p<0.001) Omicron infections within 3 months, as well as within 3 months or more (VED=30% (95%CI 24%-37%), p<0.001 for any, VED=18% (95%CI 13%-23%), p<0.001 for severe and VED=37% (95%CI 29%-46%), p<0.001 for symptomatic infections). The meta-regression analysis of overall vaccines revealed that the full dose VE against any and symptomatic Omicron infections were significantly reduced each month by 3.0% (95%CI 0.9%-4.8%, p=0.004) and 5.2% (95%CI 3.3%-7.1%, p=0.006), respectively; whereas booster dose effectiveness against severe and symptomatic Omicron infections were decreased by 3.7% (95%CI 5.1%-12.6%, p=0.030) and 3.9% (95%CI 1.2%-6.5%, p=0.006), respectively. Interpretation Compared to full dose only, a booster dose addition provides better protection against B.1.1.529 infection. Although the VE estimates of Ad26.COV2.S, BNT162b2, ChAdOx1 nCov-19, and mRNA-1273 vaccines against B.1.1.529 infection after both full and booster doses are generally moderate, and the booster dose provides excellent protection against severe infection, it is important to note that the VE estimates decline over time, suggesting the need for a regular Covid-19 booster injection after certain period of time to maintain VE.

Objective Pregnancy is a risk factor for severe Covid-19. Looking for safe vaccines that evoke protective maternal and fetal antibody response is important. Methods We searched from registries (ClinicalTrials.gov, the WHO Clinical Trial Registry, and the EU Clinical Trial Registry) and databases (MEDLINE, ScienceDirect, Cochrane Library, Proquest, and Springer) up until June 20, 2021. Articles were selected based on inclusion and exclusion criteria after duplicates were removed. Infection rate, maternal antibody response, placental antibody transfer, and adverse events were described. This systematic review was performed with quality assessment and semi-quantitative synthesis according to PRISMA guidelines. Results Twelve observational studies with a total of 40.509 pregnant women included. The mRNA based vaccines (Pfizer-BioNTech and Moderna) can prevent future SARS-CoV-2 infections (p=0.0004). Both vaccines did not affect pregnancy, delivery, and neonatal outcomes. The most commonly encountered adverse reactions are injection-site pain, fatigue, and headache but only transient. Antibody responses were rapid after the prime dose of vaccines. After booster, antibody responses were higher and associated with better placental antibody transfer. Longer intervals between first vaccination dose and delivery were also associated with higher antibody fetal IgG and better antibody transfer ratio. Conclusions The Pfizer-BioNTech and Moderna vaccines are efficacious for preventing future SARS-CoV-2 infections. These vaccines can be considered as a safe option for pregnancy and their fetus. Two doses of vaccines were recommended for more robust maternal and fetal antibody responses. Longer latency was associated with higher fetal antibody responses. Systematic Review Registration PROSPERO (CRD42021261684)