SARS-CoV-2 seroprevalence and gender-related haematological features in asymptomatic blood donors

Abstract

BackgroundSeroprevalence analysis of SARS-CoV-2 is one of the keys to accurately monitor pandemics and help the authorities make health decisions and adjust the current social interventions. The aim of this study was to determine retrospective seroprevalence evolution among blood donors along prepandemic months, and the first wave in Spain. A secondary objective was to determine whether age, blood group or haematological parameters are related to recent past infection.Material and MethodsA total of 12719 donations SARS-CoV-2 from July 2019 to October 2020 were analysed. Donors were 60.9% males and their average age was 46+/-13. An automated chemiluminiscence double-antigen sandwich immunoassay for the in vitro semi quantitative detection of total antibodies to SARS-CoV-2 in human serum and plasma was performed.ResultsSeropositivity donation rate grew up from week 11 to week 21, reaching plateau by near 8% donations, sustained until week 43 when 2nd wave arose in our country. 6.7% individuals were positive by the end of 1st wave. No differences by sex age or blood group were found regarding antibodies. Lymphocyte were significantly higher in positive woman as compared to negative ones and haemoglobin were lower in positive men as compared to negative ones.DiscussionSeroprevalence due to asymptomatic cases would be equivalent to that of general population. Sex and age would not affect COVID-19 susceptibility but its severity. Gender differences are present even in asymptomatic individuals: females are possibly protected by their relative lymphocytosis and neutropenia whereas males are would be weaker as seropositive men show a decrease of haematocrit and haemoglobin. Further studies are needed to confirm these gender differences not only in severe but as well in asymptomatic cases as they can help better understand COVID19 pathogenesis and prognosis.

Persistence of SARS-CoV-2 total immunoglobulins in a series of convalescent plasma and blood donors

“…The 120,082 donations from 77,259 donors collected from 13/01/2020 to 03/03/2021 were systematically randomized to select a minimum of 127 donations per week, calculated on the basis of the total number of donations and the length of the analysis period. 13,795 samples from 12,741 donors were analysed for a seroprevalence study [ 13 ]. 2,432 donation samples came from 1107 repeat donors.…”

“…Elecsys® Anti-SARS-CoV-2 (Roche, Basel, Switzerland‎) detects antibodies correlating with virus-neutralizing ones and is therefore useful to help characterize the immune reaction to SARS-CoV-2 [ 6 , 11 , 12 ]. Immunoassay was validated as described in [ 13 ]. The cut-off was that recommended by the manufacturer (OD>1 to report reactivity).…”

“…The recording of the first cases in Spain began in January 2020. Our first positive donations are from 2019, possibly due to cross-reaction to previous coronaviruses [ 13 ] but we decided to start this series in January 2020, after WHO issued a comprehensive package of technical guidance online with advice to all countries on how to detect, test and manage potential cases.…”

Long term positivity of SARS-CoV-2 total immunoglobulins in convalescent plasma and blood donors

“…There are recently described early cases in France [10], arising the question of whether the pathogen could have been circulating even before the recording of the first cases in Spain by January 31 st , 2020. Our fist positive donations are from 2019, possibly due to cross-reaction to previous coronaviruses [11] but we decided to start our series on January 13 th , the donation date of our first positive after WHO issued a comprehensive package of technical guidance online with advice to all countries on how to detect, test and manage potential cases.…”