Background: The pandemic of COVID-19 raised the urgent need of safe and efficacious vaccines against SARS-CoV-2. We evaluated the efficacy and safety of a new SARS-CoV-2 virus receptor-binding domain (RBD) vaccine. Methods: A phase 3, multicentre, randomised, double-blind, placebo-controlled trial was carried out at 18 clinical sites in three provinces of the south-eastern region of Cuba. Subjects (healthy or those with controlled chronic diseases) aged between 19 and 80 years, who gave written informed consent were eligible. Subjects were randomly assigned (1:1, in blocks) to two groups: placebo, and 50 mcg RBD vaccine (Abdala). The product was administered intramuscularly, 0.5 mL in the deltoid region, in a three dose immunization schedule at 0-14-28 days. The organoleptic characteristics and presentations of vaccine and placebo were identical. All participants (subjects, clinical researchers, statisticians, laboratory technicians, and monitors) remained blinded during the study period. The main endpoint was to evaluate the efficacy of the Abdala vaccine in the prevention of symptomatic COVID-19. The trial is registered with the Cuban Public Registry of Clinical Trials, RPCEC00000359. Findings: Between March 22 to April 03, 2021, 48290 subjects were included (24144 and 21146 in the placebo and Abdala groups, respectively). The product was well tolerated. No severe adverse events with demonstrated cause-effect relationship attributable to vaccine were reported. The incidence of adverse reactions in the placebo and Abdala vaccine arms were 446/24144 (1.9%) and 615/24146 (2.5%), respectively. Adverse reactions were mostly mild, and from the injection site, which resolved in the first 24-48 hours. The Abdala vaccine efficacy against symptomatic COVID-19 was 92.28% (95% CI 85.74-95.82). In the case of mild/moderate disease the vaccine efficacy was 91.96% (84.69-95.78) and 94.46% (58.52-99.28) for the severe forms (serious/critical disease). There were five critical patients (of which four died), all in the placebo group, indicating that Abdala vaccine efficacy for both conditions was of 100%. Interpretation: The Abdala vaccine was safe, well tolerated, and highly effective, fulfilling the WHO target product profile for COVID-19 vaccines. Funding: Centre for Genetic Engineering and Biotechnology (CIGB), Havana, Cuba.

INTRODUCTION Ferritin is the best biomarker for assessing iron defi ciency, but ferritin concentrations increase with infl ammation. Several adjustment methods have been proposed to account for infl ammation's eff ect on iron biomarker interpretation. The most recent and highly recommended method uses linear regression models, but more research is needed on other models that may better defi ne iron status in children, particularly when distributions are heterogenous and in contexts where the eff ect of infl ammation on ferritin is not linear.OBJECTIVES Assess the utility and relevance of quadratic regression models and quantile quadratic regression models in adjusting ferritin concentration in the presence of infl ammation. METHODSWe used data from children aged under fi ve years, taken from Cuba's national anemia and iron defi ciency survey, which was carried out from 2015-2018 by the National Hygiene, Epidemiology and Microbiology Institute. We included data from 1375 children aged 6 to 59 months and collected ferritin concentrations and two biomarkers for infl ammation: C-reactive protein and α-1 acid glycoprotein. Quadratic regression and quantile regression models were used to adjust for changes in ferritin concentration in the presence of infl ammation. RESULTSUnadjusted iron defi ciency prevalence was 23% (316/1375). Infl ammation-adjusted ferritin values increased iron-defi ciency prevalence by 2.6-4.5 percentage points when quadratic regression correction model was used, and by 2.8-6.2 when quantile regression was used. The increase when using the quantile regression correction model was more pronounced and statistically signifi cant when both infl ammation biomarkers were considered, but adjusted prevalence was similar between the two correction methods when only one biomarker was analyzed.CONCLUSIONS The use of quadratic regression and quantile quadratic regression models is a complementary strategy in adjusting ferritin for infl ammation, and is preferable to standard regression analysis when the linear model's basic assumptions are not met, or when it can be assumed that ferritin-infl ammation relationships within a subpopulation may deviate from average trends.KEYWORDS Alpha-1-acid glycoprotein, C-reactive protein, anemia, iron defi ciency, ferritin, acute phase protein, Cuba

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This study aims to evaluate the prevalence of anemia and iron deficiency in women of reproductive age and the association with inflammation, global overweight, adiposity, and menorrhagia. A sample design of women of reproductive age from the Eastern, Central, and Havana Regions was carried out. Biochemical determinations of hemoglobin, serum ferritin, soluble transferrin receptors, leukocytes, C-reactive protein, alpha-1 acid glycoprotein, and homocysteine were performed. Serum ferritin was also adjusted by inflammation. Nutritional status was assessed, and menstrual characteristics were collected by survey. A total of 742 women were studied. The prevalence of anemia was 21.4%, iron storage deficiency at 16.0%, and erythropoietic dysfunction at 5.4%, with inflammation at 47.0% and elevated homocysteine at 18.6%. Global overweight was 46.2% and increased adiposity at 58.4%. Anemia is associated with iron deposition deficiency (OR = 3.023 (1.816–5.033)) and with erythropoietic deficiency (OR = 5.62 (3.03–10.39)), but not with inflammation, global overweight, and adiposity. Global overweight was found to be associated with inflammation (OR = 2.23 (1.41–3.53)). Anemia was associated with heavy menstrual bleeding (OR = 1.92 (1.34–2.76)). Homocysteine was associated with inflammation (OR = 2.05 (1.08–3.90)), but not with anemia. In conclusion, anemia in Cuba is classified as a moderate public health problem, but not iron deficiency. A high prevalence of overweight and obesity was found, associated with inflammation, but not with anemia or iron deficiency. Heavy menstrual bleeding is a factor associated with anemia.