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INTRODUCTION Anemia is a public health problem worldwide and is most prevalent in preschool children, for whom it is the most frequent cause of nutritional defi cits. In turn, iron defi ciency is the main cause of anemia, affecting 43% of children globally. Previous studies in Cuba show rates of iron defi ciency in preschool children between 38.6% and 57.6%, higher in infants (71.2% to 81.1%). WHO recommends using serum ferritin as an indicator of iron defi ciency accompanied by acute (C-reactive protein) and chronic (α1-acid glycoprotein) infl ammation biomarkers. OBJECTIVE Assess how infl ammation affects measuring and reporting of iron-defi ciency anemia rates in Cuban preschool children.METHODS Data were obtained from serum samples contained in the National Anemia and Iron Defi ciency Survey, and included presumably healthy preschool Cuban children (aged 6-59 months). Serum samples were collected from 1375 children from randomly selected provinces in 4 regions of the country from 2014 through 2018. We examined the association between ferritin and two infl ammatory biomarkers: C-reactive protein and α1-acid glycoprotein. Individual infl ammation-adjusted ferritin concentrations were calculated using four approaches: 1) a higher ferritin cut-off point (<30 g/L); 2) exclusion of subjects showing infl ammation (C-reactive protein >5 mg/L or α1-acid glycoprotein >1 g/L); 3) mathematical correction factor based on C-reactive protein or α1-acid glycoprotein; and 4) correction by regression with the method proposed by the Biomarkers Refl ecting Infl ammation and Nutritional Determinants of Anemia Group. We estimated confi dence intervals of differences between unadjusted prevalence and prevalence adjusted for infl ammation by each method. RESULTSThe proportion of children with infl ammation according to C-reactive protein concentrations >5 mg/L was lower (11.1%, 153/1375) than the proportion measured according to the concentrations of α1-acid glycoprotein, at >1 g/L (30.8%, 424/1375). The percentage of children with high concentrations of at least one of the aforementioned biomarkers was 32.7% (450/1375). Thus, each correction method increased the observed prevalence of iron defi ciency compared to unadjusted estimates (23%, 316/1375). This increase was more pronounced when using the internal regression correction method (based only on C-reactive protein) or the method based on a higher cut-off point. Adjustment using all four methods changed estimated iron defi ciency prevalence, increasing it from 0.1% to 8.8%, compared to unadjusted values. CONCLUSION One-third of preschool children had biomarkers indicating elevated infl ammation levels. Without adjusting for infl ammation, iron defi ciency prevalence was underestimated. The signifi cant disparity between unadjusted and infl ammationadjusted ferritin when using some approaches highlights the importance of selecting the right approach for accurate, corrected measurement. The internal regression correction approach is appropriate for epidemiological studies because...

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.

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