Absolute Neutropenia and Infection Development in Premature Infants in Early Neonatal Period: Cross-Sectional Study

Background. Premature infants have high risk of developing of neutropenia and infections in the early neonatal period. The correlation of these events requires further studies.Objective. The aim of the study was to investigate the frequency of absolute neutropenia and infectious complications cases in premature infants in the early neonatal period with estimation of phenotypical and functional features of cord blood neutrophils.Methods. The study included premature infants (gestational age 25–36 weeks) with APGAR score < 8 on the 1st and 5th minutes of life. The frequency of absolute neutropenia (at least once < 1.5109/l) and infectious complications (localized infections of bacterial etiology, early neonatal sepsis) cases in the first 14 day of life was analysed. Additionally, we have determined the expression of CD64, CD16, CD32 by cord blood neutrophils in premature (n = 102) and mature infants (n = 30) via method of flow cytofluorometry. We have used FITC labeled Escherichia coli to estimate their phagocytic activity, and stimulation of E. coli neutrophils in the presence of 5 mM of dihydrorhodamine 123 to estimate their stimulation index (ratio of mean fluorescent intensity (MFI) of activated neutrophils in stimulated samples and in negative controls, E. coli free samples).Results. The episodes of absolute neutropenia in the first 14 days of life were recorded in 17 cases, infectious complications — in 87 children (in 24 cases — sepsis) in the group of premature infants. The frequency of infectious complications in premature children did not correlate with the frequency of absolute neutropenia episodes. Cord blood neutrophils in premature infants had higher CD64 expression and, on the contrary, lower CD16 expression, as well as low phagocytic activity and stimulation index value (in all cases p < 0.001).Conclusion. Absolute neutropenia in premature infants in early neonatal period does not correlate with high risk of bacterial infections. However, cord blood neutrophils in premature infants had lower functional activity

Sputnik V Effectiveness against Hospitalization with COVID-19 during Omicron Dominance

Mass vaccination campaigns against COVID-19 affected more than 90% of the population in most developed countries. The new epidemiologic wave of COVID-19 has been ongoing since the end of 2021. It is caused by a virus variant B.1.1.529, also known as “Omicron” and its descendants. The effectiveness of major vaccines against Omicron is not known. The purpose of this study is to evaluate the efficacy of the Sputnik V vaccine. The main goal is to assess its protection against hospitalization in the period of Omicron dominance. We conducted our study based on a large clinical center in Moscow (Russia) where 1112 patients were included. We used the case-population method to perform the calculations. The data we obtained indicate that the Omicron variant causes at least 90% of infections in the studied cohort. The effectiveness of protection against hospitalization with COVID-19 in our study was 85.9% (95% CI 83.0–88.0%) for those who received more than one dose. It was 87.6% (95% CI 85.4–89.5%) and 97.0% (95% CI 95.9–97.8%) for those who received more than two or three doses. The effectiveness in cases of more severe forms was higher than for less severe ones. Thus, present study indicates the high protective efficacy of vaccination against hospitalization with COVID-19 in case of Omicron lineage