Asymptomatic Donors Research Articles

A Longitudinal Study of Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Response in a Subset of United States Blood Donors.

Blood donors were tested for antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); resulting antibody levels were monitored over time. Donors reactive to anti-SARS-CoV-2 spike protein (S1-total antibodies) participated in a follow-up study of 18 months. Testing for nucleocapsid antibodies distinguished between vaccination and infection. Vaccination and symptom information were collected for anti-S1-reactive donors by completing a survey. The majority of 249 followed donors were over 60 years old (54%), White (90%), and female (58%); 83% had not been vaccinated at enrollment, but by study completion, only 29% remained nonvaccinated. Of the 210 (84%) anti-N-reactive donors, 138 (66%) reported vaccination, whereas 37 (95%) of donors vaccinated and anti-N negative at enrollment remained uninfected. Vaccinated (2 doses) and infected donors showed a steady increase in anti-S1 that increased markedly for vaccinated donors after a booster and infected donors after vaccination (slightly higher for those with hybrid immunity), whereas anti-N levels declined. Most surveyed nonvaccinated donors (65%) reported symptoms, whereas 85% of vaccinated donors were asymptomatic. A coronavirus disease 2019 (COVID-19) diagnosis was reported by 48 (31%) nonvaccinated and 3 (8%) vaccinated donors. Of asymptomatic donors, 38% never tested diagnostically for COVID-19, and 35% tested negative, suggesting an absence of knowledge of the infection. Healthy blood donors were vaccinated at high rates and remained mostly asymptomatic and noninfected, whereas approximately two thirds of infected donors reported symptoms. Anti-S1 levels increased while anti-N decreased over 18 months but remained comparable between vaccinated and hybrid immune individuals with dramatic anti-S1 increases after vaccination or boosting.

Monkeypox a Concern for Donor-derived Infection?

Monkeypox a Concern for Donor-derived Infection?

The impact of gastrointestinal tract infection on acquiring dengue fever virus infection and haemorrhagic fever in Jeddah City, Saudi Arabia

This study aimed to investigate the relationship between gastrointestinal tract infection and dengue hemorrhagic fever. Dengue hemorrhagic fever is a syndrome caused by the dengue virus and primarily affects children below ten years of age and is spread by the Aedes aegypti mosquito. Gastrointestinal tract infection is a bacterial and parasitic infection that leads to gastrointestinal tract inflammation which involves the small intestine and the stomach. The relationship between the two can be manifested by gastrointestinal bleeding, acute pancreatitis, and fulminant liver failure. In this research work, 600 blood and feces samples of different ages and sex (7-8 worms) were collected from Jeddah city. From the blood samples, serum was made and stored at -20°C until use. The frozen sera samples were investigated for sero-detection of DENV-NS1 antigen as a rapid, sensitive, and cost-effective test to detect asymptomatic acute DENV-infected donors and anti-DENV IgM and IgG antibodies. Feces samples were processed for the detection of parasites. The data acquired from these samples of all the 600 participants were analyzed and interpreted, followed by statistical analysis using GraphPad Prism 5.0 software. All the values were considered significant, which showeda value of less than 0.05. Results were expressed aswith the range. This article documents that gastrointestinal tract manifestations frequently occur among patients with dengue hemorrhagic fever. There are close relationships between gastrointestinal tract infection and dengue hemorrhagic fever. In current work, it was established that dengue fever leads to gastrointestinal tract bleeding in the presence of intestinal parasites. Therefore, failure to identify the patients with this infection early enough can lead to an increased morbidity and mortality rate.

Analysis of SARS-CoV-2 in Corneal Tissue of Deceased Asymptomatic Novel Coronavirus Disease 2019 Donors.

The aim of this study was to analyze the presence of the SARS-CoV-2 virus in the corneal tissue of asymptomatic deceased novel coronavirus disease 2019 (COVID-19) patients. This was a cross-sectional study performed at a tertiary eye hospital. All corneas of the deceased asymptomatic donors who tested positive for SARS-CoV-2 on a nasopharyngeal swab at the time of corneal tissue harvesting were included in the study. Histopathological examination and immunohistochemistry were performed. mRNA in situ hybridization for SARS-CoV-2 was performed in all specimens that showed positive immunostaining. The main outcome measure was the presence of SARS-CoV-2 virus in the corneal tissues. Twenty-two corneal tissues of 11 donors were analyzed. The mean age was 72.2 ± 14.2 years. On histological examination, no signs of inflammation or any other abnormalities were detected in the cornea and adjacent bulbar conjunctiva. Immunohistochemistry revealed faint to moderate cytoplasmic staining in the basal layer of the corneal epithelium in 8 specimens from 5 patients. None of the specimens with positive immunostaining showed the presence of SARS-CoV-2 mRNA. In line with previous studies , our study also reflects the absence of SARS-CoV-2 viral mRNA in corneal tissues of clinically asymptomatic deceased COVID-19 donors, thereby indicating a probable low risk of transmission of the SARS-CoV-2 virus through the transplantation of corneas from donors who tested positive for, but were asymptomatic for COVID-19. In addition, further studies on the subject should include histopathological examination because of the false positive and negative rates of molecular tests.

Organ Transplant From SARS-CoV-2–Positive Donors: A Brazilian Experience

Since March 2022, donors with detectable SARS-CoV-2 RNA have been accepted for extrapulmonary organ transplants in Brazil. In this report, we described 11 successful organ transplants (6 kidney, 5 liver) from 5 asymptomatic infected donors.

Prevalence of Chikungunya, Dengue and Zika viruses in blood donors: a systematic literature review and meta-analysis.

Blood transfusion centres should understand the epidemiology of emerging diseases that are transmissible through the transfusion of blood components. The risk of transmission of arboviruses through this route has become apparent in recent years. The aim of our study is to summarise the reported prevalence (viraemic rate, seroprevalence and/or antigen detection) of Chikungunya (CHIKV), Dengue (DENV) and Zika (ZIKV) viruses in blood donors according to screening test used and world region. We conducted a systematic literature review and meta-analysis having searched for information in the main bibliographic databases (MEDLINE, Embase, and Scopus). The prevalence for each of the viruses was calculated according to the screening test used and geographic location. We included 18 records on CHIKV, 71 on DENV, and 27 on ZIKV. The highest prevalences of RNA for CHIKV were 1.9% in Puerto Rico (2014), 1.0% in Thailand (2009), and 1.0% in French Polynesia (2014-15). The highest prevalences of RNA for DENV were 5.5% in Saudi Arabia (2015-16), 2.3% in Madeira, Portugal (2012-13), and 0.6% in Brazil (2012). The highest prevalences of RNA for ZIKV were 2.8% in French Polynesia (2013-14), 2.7% in Brazil (2015-16), and 1.8% in Martinique (2016). Overall seroprevalence, as assessed by IgG antibodies, was 21.6% for CHIKV, 24.0% for DENV, and 5.1% for ZIKV. Our study shows a high proportion of donors who are viraemic and asymptomatic, especially during outbreaks, with prevalences surpassing 5% for DENV, 1% for CHIKV, and 2% for ZIKV. These data confirm a clear threat to blood transfusion safety. The elevated seroprevalence for these three arboviruses is also indicative of their wide circulation in populations, correlating with an increased risk of infected but asymptomatic donors. Health centres and institutions must address this threat, especially in tropical regions where the biggest outbreaks occur.

POS-007 COMPLEMENT RELATED GENETIC MUTATIONS IN ASYMPTOMATIC KIDNEY DONORS: A SERIES OF THREE RARE CASES

POS-007 COMPLEMENT RELATED GENETIC MUTATIONS IN ASYMPTOMATIC KIDNEY DONORS: A SERIES OF THREE RARE CASES

Presence of SARS-CoV-2 RNA in human corneal tissues donated in Italy during the COVID-19 pandemic

ObjectiveTo analyse corneal tissues from asymptomatic donors with a postmortem nasopharyngeal swab tested positive for the presence of SARS-CoV-2 RNA, and therefore, understand the role that corneal transplantation may have...

First computational design using lambda-superstrings and in vivo validation of SARS-CoV-2 vaccine

Coronavirus disease 2019 (COVID-19) is the greatest threat to global health at the present time, and considerable public and private effort is being devoted to fighting this recently emerged disease. Despite the undoubted advances in the development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, uncertainty remains about their future efficacy and the duration of the immunity induced. It is therefore prudent to continue designing and testing vaccines against this pathogen. In this article we computationally designed two candidate vaccines, one monopeptide and one multipeptide, using a technique involving optimizing lambda-superstrings, which was introduced and developed by our research group. We tested the monopeptide vaccine, thus establishing a proof of concept for the validity of the technique. We synthesized a peptide of 22 amino acids in length, corresponding to one of the candidate vaccines, and prepared a dendritic cell (DC) vaccine vector loaded with the 22 amino acids SARS-CoV-2 peptide (positions 50-71) contained in the NTD domain (DC-CoVPSA) of the Spike protein. Next, we tested the immunogenicity, the type of immune response elicited, and the cytokine profile induced by the vaccine, using a non-related bacterial peptide as negative control. Our results indicated that the CoVPSA peptide of the Spike protein elicits noticeable immunogenicity in vivo using a DC vaccine vector and remarkable cellular and humoral immune responses. This DC vaccine vector loaded with the NTD peptide of the Spike protein elicited a predominant Th1-Th17 cytokine profile, indicative of an effective anti-viral response. Finally, we performed a proof of concept experiment in humans that included the following groups: asymptomatic non-active COVID-19 patients, vaccinated volunteers, and control donors that tested negative for SARS-CoV-2. The positive control was the current receptor binding domain epitope of COVID-19 RNA-vaccines. We successfully developed a vaccine candidate technique involving optimizing lambda-superstrings and provided proof of concept in human subjects. We conclude that it is a valid method to decipher the best epitopes of the Spike protein of SARS-CoV-2 to prepare peptide-based vaccines for different vector platforms, including DC vaccines.

The serum of COVID-19 asymptomatic patients up-regulates proteins related to endothelial dysfunction and viral response in circulating angiogenic cells ex-vivo

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already caused 6 million deaths worldwide. While asymptomatic individuals are responsible of many potential transmissions, the difficulty to identify and isolate them at the high peak of infection constitutes still a real challenge. Moreover, SARS-CoV-2 provokes severe vascular damage and thromboembolic events in critical COVID-19 patients, deriving in many related deaths and long-hauler symptoms. Understanding how these processes are triggered as well as the potential long-term sequelae, even in asymptomatic individuals, becomes essential.MethodsWe have evaluated, by application of a proteomics-based quantitative approach, the effect of serum from COVID-19 asymptomatic individuals over circulating angiogenic cells (CACs). Healthy CACs were incubated ex-vivo with the serum of either COVID-19 negative (PCR −/IgG −, n:8) or COVID-19 positive asymptomatic donors, at different infective stages: PCR +/IgG − (n:8) and PCR −/IgG + (n:8). Also, a label free quantitative approach was applied to identify and quantify protein differences between these serums. Finally, machine learning algorithms were applied to validate the differential protein patterns in CACs.ResultsOur results confirmed that SARS-CoV-2 promotes changes at the protein level in the serum of infected asymptomatic individuals, mainly correlated with altered coagulation and inflammatory processes (Fibrinogen, Von Willebrand Factor, Thrombospondin-1). At the cellular level, proteins like ICAM-1, TLR2 or Ezrin/Radixin were only up-regulated in CACs treated with the serum of asymptomatic patients at the highest peak of infection (PCR + /IgG −), but not with the serum of PCR −/IgG + individuals. Several proteins stood out as significantly discriminating markers in CACs in response to PCR or IgG + serums. Many of these proteins particiArticle title: Kindly check and confirm the edit made in the articletitle.pate in the initial endothelial response against the virus.ConclusionsThe ex vivo incubation of CACs with the serum of asymptomatic COVID-19 donors at different stages of infection promoted protein changes representative of the endothelial dysfunction and inflammatory response after viral infection, together with activation of the coagulation process. The current approach constitutes an optimal model to study the response of vascular cells to SARS-CoV-2 infection, and an alternative platform to test potential inhibitors targeting either the virus entry pathway or the immune responses following SARS-CoV-2 infection.

Seroprevalence of SARS-CoV-2 antibodies among blood donors in Québec: an update from a serial cross-sectional study.

ObjectivesWe previously estimated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies following the first pandemic wave at 2.23% in Québec, Canada. Following the much bigger second wave in fall 2020 and early 2021, we estimated the seroprevalence of anti-SARS-CoV-2 in Québec during the first months of 2021.MethodsBlood samples from regular, asymptomatic (for ≥ 14 days) donors were collected between January 25, 2021 and March 11, 2021. Anti-SARS-CoV-2 seropositivity was assessed using an enzyme-linked immunosorbent assay that captures antibodies directed against the receptor binding domain of the SARS-CoV-2 spike (and hence cannot discriminate between infection- and vaccine-induced seropositivity). Seroprevalence estimates were adjusted for regional distribution, age, and sex.ResultsSamples from 7924 eligible donors were analyzed, including 620 (7.8%) vaccinated donors and 7046 (88.9%) unvaccinated donors (vaccination status unknown for 258 (3.3%) donors). Overall, median age was 51 years; 46.4% of donors were female. The adjusted seroprevalence was 10.5% (95% CI = 9.7–11.3) in the unvaccinated population and 14.7% (95% CI = 13.8–15.6) in the overall population. Seroprevalence gradually decreased with age and was higher among donors who self-identified as having a racial/ethnic background other than white, both in the overall and in the unvaccinated populations.ConclusionThe seroprevalence of SARS-CoV-2 antibodies significantly increased in Québec since spring 2020, with younger persons and ethnic minorities being disproportionately affected. When compared with the cumulative incidence rate reported by public health authorities (i.e., 3.3% as of March 11, 2021), these results suggest that a substantial proportion of infections remain undetected despite improvements in access to COVID-19 testing.Supplementary InformationThe online version contains supplementary material available at 10.17269/s41997-022-00622-y.

Blood supply and transfusion safety during the COVID-19 pandemic

Introduction: The COVID-19 pandemic has put a strain on transfusion practices and safety. The Scientific Committees consider that the COVID-19 pandemic presents a potential risk of reducing and compromising the blood product supply and expressed considerable concern about transfusion safety. Method: In this concise review, we provide an overview of the implications of COVID-19 for blood safety and sufficiency during the initial phases of the pandemic. We searched the PubMed database, the websites of the World Health Organization, the European Centre for Disease Prevention and Control, the US Communicable Diseases Center. We used the keywords COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the impact of COVID-19 on the blood supply, impact of COVID-19 on blood collection, COVID-19 and transfusion safety, the transmission of SARS-CoV-2 through blood transfusion, COVID-19 symptoms, asymptomatic blood donor, COVID-19 patients. Results: Data provided from blood transfusion centers and blood banks worldwide show that the COVID-19 pandemic has affected the activities of the blood supply system. It has impacted blood collections and caused a significant decrease in blood donors. The estimated asymptomatic infection rate was 15–46% of SARS-CoV-2 infections. The estimated incubation ranges are between 2 and 11 days, and almost all infections developed symptoms by day 14. The RNAemia phase of SARS-CoV-2 appears to be brief and low level, is typically associated with more severe disease, and is not demonstrated to be an infectious virus. It is detectable in only a tiny proportion of patients. Post-donation, post-transfusion information, and molecular testing of swab samples collected from asymptomatic donors at risk for COVID-19 provided data supporting the absence of transfusion transmission (TT) of COVID-19. The TT risk is currently theoretical. To prevent and minimize respiratory transmission of SARS-CoV-2 to donors and staff while donating blood, blood centers have had to activate their emergency plans and propose appropriate response measures. Conclusion: The COVID-19 pandemic has a significant impact on blood transfusion activities worldwide. The risk of transmission of COVID-19 through transfusion of blood collected from asymptomatic individuals is now only theoretical and likely minimal. Blood systems should adopt a national approach for coherence and coordination to ensure public confidence in blood safety and supply.

SEROPREVALENCE OF HUMAN PARVOVIRUS B19 IgM AND IgG AMONG ASYMTOMATIC DONORS IN LAGOS, NIGERIA

Human parvovirus B19 is one of the emerging transfusion transmitted infections. Infection with B19 is widespread. There are limited data concerning Nigerian donors with B19 in spite of implications of such a dearth of data on health policy formation. The aim of the present study was to establish the seroprevalence of parvovirus B19 IgG and IgM antibodies among healthy blood donors in Lagos, Nigeria. Blood samples were collected between October-December 2012 from 170 asymptomatic healthy donors between ages of 20-54 years and screened for IgG and IgM antibodies using recombinant enzyme linked immunorsorbent assay kits (r-biopharm Diagnostics, Darmstadt, Germany). Net prevalence of IgM and IgG antibodies to human parvovirus B19 in this study was 65(37.6%) and 106(61.3%) respectively. A total of 39(22.9%) out of 173 blood donors screened in this research had anti- B19 antibodies (dual positivity) in their sera. Age had no statistically significant effect on anti-B19 seroprevalence among donors screened. The prevalence of parvovirus B19 among healthy donors in our study is high, and may pose adverse transfusion risk among the recipients of blood and blood products who have no detectable antibodies to parvovirus B19. This work therefore recommends routine screening for parvovirus B19 IgM antibody in blood meant for transfusion and accompanying clinical management of positive cases should be made compulsory for all donors.

Therapeutic potential of living donor liver transplantation from heterozygous carrier donors in children with propionic acidemia

BackgroundCurrent world experience regarding living donor liver transplantation (LDLT) in the treatment of propionic acidemia (PA) is limited, especially in terms of using obligate heterozygous carriers as donors. This study aimed to evaluate the clinical outcomes of LDLT in children with PA.MethodsFrom November 2017 to January 2020, 7 of the 192 children who underwent LDLT at our institution had been diagnosed with PA (median age, 2.1 years; range, 1.1–5.8 years). The primary indication for transplantation was frequent metabolic decompensations in 6 patients and preventative treatment in 1 patient. Of the seven parental living donors, six were genetically proven obligate heterozygous carriers.ResultsDuring a median follow-up of 23.9 months (range, 13.9–40.2 months), all patients were alive with 100% allograft survival, and no severe transplant-related complications occurred. In the case of liberalized protein intake, they did not suffer metabolic decompensation or disease-related complications and made progress in neurodevelopmental delay and body growth, as well as blood and urinary metabolite levels. In one patient with pre-existing mild dilated cardiomyopathy, her echocardiogram results completely normalized 13.8 months post-transplant. All living donors recovered well after surgery, with no metabolic decompensations or procedure-related complications. Western blotting revealed that the hepatic expressions of PCCA and PCCB in one of the heterozygous donors were comparable to those of the normal healthy control at the protein level.ConclusionsLDLT using partial liver grafts from asymptomatic obligate heterozygous carrier donors is a viable therapeutic option for selected PA patients, with no negative impact on donors’ and recipients' clinical courses.

SARS-CoV-2 neutralizing capacity among blood donors without prior COVID-19 symptomatic history vs. blood donors with prior COVID-19 symptomatic history: A comparative study.

IntroductionThough moderate to severely ill COVID-19 patients are being treated using COVID Convalescent plasma across the world, there is a lack of standardization or information about the relative neutralizing capacity of antibodies from convalescent plasma donors. The current study aimed to compare the neutralizing antibody inhibition levels between COVID-Convalescent plasma from apheresis donors who had symptomatic COVID-19 history and asymptomatic blood donors, i.e., whole blood donors without prior any COVID-19 positive diagnosis nor symptoms/contact history related to COVID-19.MethodsObservational study conducted at the Blood Centre, Tertiary Care Hospital, South India on blood donor samples during the period July–December 2020. A total of 90 samples (43 convalescent plasma donors and 47 whole blood donors) were tested for SARS-CoV-2-IgG and Neutralising antibodies.ResultsNo significant difference in neutralization capacity was observed between these symptomatic vs. asymptomatic donors. Also, inhibition % appeared similar in the two groups with respect to age, gender, blood group, donation status, or type of donation without any statistical significance. On analyzing the correlation between the SARS-CoV-2-IgG levels and neutralizing antibodies among the WBD and CCP, both the groups showed a positive correlation, while neutralizing antibodies showed a significant correlation with SARS-CoV-2-IgG levels among the whole blood donors (Pearson correlation P = 0.000).ConclusionNo significant difference in neutralizing antibody capacity was observed in asymptomatic whole blood donors and convalescent plasma donors. Therefore, donors having adequate levels of SARS-CoV-2-IgG antibody levels on screening can be considered for convalescent plasma donation irrespective of prior COVID-19 diagnosis or COVID-related symptoms.

Listeria monocytogenes faecal carriage is common and depends on the gut microbiota

Listeria genus comprises two pathogenic species, L. monocytogenes (Lm) and L. ivanovii, and non-pathogenic species. All can thrive as saprophytes, whereas only pathogenic species cause systemic infections. Identifying Listeria species’ respective biotopes is critical to understand the ecological contribution of Listeria virulence. In order to investigate the prevalence and abundance of Listeria species in various sources, we retrieved and analyzed 16S rRNA datasets from MG-RAST metagenomic database. 26% of datasets contain Listeria sensu stricto sequences, and Lm is the most prevalent species, most abundant in soil and host-associated environments, including 5% of human stools. Lm is also detected in 10% of human stool samples from an independent cohort of 900 healthy asymptomatic donors. A specific microbiota signature is associated with Lm faecal carriage, both in humans and experimentally inoculated mice, in which it precedes Lm faecal carriage. These results indicate that Lm faecal carriage is common and depends on the gut microbiota, and suggest that Lm faecal carriage is a crucial yet overlooked consequence of its virulence.

Transfusion-Transmitted Malaria of Plasmodium malariae in Palermo, Sicily

Transfusion-transmitted malaria (TTM) is a rare occurrence with serious consequences for the recipient. In non-endemic areas, the incidence of transmission of malaria by transfusion is very low. We report a clinical case of transfusion-transmitted malaria due to Plasmodium malariae, which happened in a patient with acute hemorrhagic gastropathy. Case presentation: In April 2019, a 70-year-old Italian man with recurrent spiking fever for four days was diagnosed with a P. malariae infection, as confirmed using microscopy and real-time PCR. The patient had never been abroad, but about two months before, he had received a red blood cell transfusion for anemia. Regarding the donor, we revealed that they were a missionary priest who often went to tropical regions. Plasmodium spp. PCR was also used on donor blood to confirm the causal link. Discussion and Conclusions: The donations of asymptomatic blood donors who are predominantly “semi-immune” with very low parasitic loads are an issue. The main problem is related to transfusion-transmitted malaria. Our case suggests that P. malariae infections in semi-immune asymptomatic donors are a threat to transfusion safety. Currently, microscopy is considered the gold standard for the diagnosis of malaria but has limited sensitivity to detect low levels of parasitemia. Screening using serological tests and molecular tests, combined with the donor’s questionnaire, should be used to reduce the cases of TTM.

Increased SARS-CoV-2 seroprevalence in healthy blood donors after the second pandemic wave in South-Eastern Italy: evidence for asymptomatic young donors as potential virus spreaders

Background Italy experienced SARS-CoV-2 spread during the second wave and the southern regions were severely affected. In this prospective study, we assessed the changes in SARS-CoV-2 seroprevalence rates in non-vaccinated blood donors to evaluate the spread of SARS-CoV-2 among healthy individuals in our geographical area. Methods 8,183 healthy blood donors visiting the Transfusion Centre at the University Hospital “Riuniti” of Foggia (Italy) to donate blood from May 2020 to March 2021 were tested twice for anti-SARS-CoV-2 antibodies by Ortho Clinical Diagnostics VITROS® 3600 through anti-SARS-CoV-2 Total and IgG reagent kit. None of the subjects had diagnosed symptomatic COVID-19 infection, and none had received vaccination. Results Overall, 516 out of 8,183 had antibodies to SARS-CoV-2 (total and IgG antibodies) (6.3%, 95% CI: 0.03–0.15%), 387 were male and 129 female. There was a significant increase of seropositive donors from May 2020 to March 2021 (p < .001). The difference in seroprevalence was significantly associated with age but not sex (2-sided p < .05 for age; 2-sided p ≥ .05 for sex) in both groups. Conclusions Our study showed a significant increase in SARS-CoV-2 seroprevalence in blood donors and suggests that asymptomatic individuals might contribute to the spread of SARS-CoV-2. These results may contribute to revised containment measures, priorities in vaccine campaigns and monitoring of seroprevalence in public places like Transfusion Centres. Serologic testing of blood donors may be relevant to monitor SARS-CoV-2 circulation in the general population.

Clinical Utility of COVID-19 Real Time-Polymerase Chain Reaction Testing of Ocular Tissues of Non-COVID-19 Cornea Donors Deemed Suitable for Corneal Retrieval and Transplantation.

The purpose of this study was to evaluate the prevalence of SARS-CoV-2 in human postmortem ocular tissues of asymptomatic donors and its implications on our eye banking protocols. The expression of SARS-CoV-2 RNA was assessed by reverse transcription-polymerase chain reaction in corneal rims and conjunctival tissues from 100 donors who were found suitable for transplantation as per the donor screening guidelines of the Global Alliance of Eye Bank Associations. The donor's clinical history and cause of death were assessed for secondary analysis. Of 200 ocular tissues (100 corneal and 100 conjunctival) from the same 1 eye of 100 surgical-intended donors, between September 2020 and April 2021, the overall positivity rate for SARS-CoV-2 was ∼1% (2/200). Both the ocular samples that tested positive were conjunctival biopsies (2/100, 2%), whereas corneal samples were negative (0/100, 0%) in both donors. The causes of donor death were trauma in 51 donors, suicide in 33, cardiac arrest in 7, electric shock in 5, metabolic cause in 2, malignancy in 1, and snake bite in 1. None of the donors had a medical history suggestive of COVID infection or possible contact. None of the recipients from the donors were reported to have any systemic adverse event after keratoplasty until the follow-up of 6 weeks. The overall prevalence of SARS-CoV-2 was 1% (2% for conjunctival and 0% for corneal samples, P value = 0.5) in the donors who were found suitable for cornea recovery and transplantation. The findings of exceptionally low positive rates in our samples validate the criticality of history-based donor screening and do not support the necessity of postmortem PCR testing as a criterion for procurement and subsequent use for corneal transplantation.

Trends and risk factors of SARS-CoV-2 infection in asymptomatic blood donors.

BackgroundA large proportion of SARS‐CoV‐2‐infected individuals does not develop severe symptoms. Serological tests help in evaluating the spread of infection and disease immunization. The aim of this study was to prospectively examine the trends and risk factors of SARS‐CoV‐2 infection in blood donors.Study design and methodsWe screened 8798 asymptomatic donors presenting in Milan from July 2020 to February 2021 (10,680 presentations) before the vaccination campaign for anti‐nucleoprotein (NP) antibodies, and for anti‐spike receptor‐binding domain (RBD) antibodies and nasopharyngeal swab PCR in those who tested positive.ResultsThe prevalence of anti‐NP+/RBD+ tests increased progressively with time up to ~15% (p < .0001), preceded by a peak of PCR+ tests. Anti‐RBD titers were higher in anti‐NP IgG+/IgM+ than in IgG+/IgM− individuals and in those with a history of infection (p < .0001); of these 197/630 (31.2%) displayed high titers (>80 AU/ml). Anti‐RBD titers declined during follow‐up, depending on baseline titers (p < .0001) and time (p = .025). Risk factors for seroconversion were a later presentation date and non‐O ABO blood group (p < .001). A positive PCR was detected in 0.7% of participants in the absence of SARS‐CoV‐2 viremia.ConclusionsDuring the second wave of SARS‐CoV‐2 infection in Northern Italy, we detected an increase in seroprevalence in healthy blood donors from ~4% to ~15%, with a trend paralleling that observed in the general population. Seroconversion was more frequent in carriers of non‐O blood groups. The persistence of anti‐RBD antibodies was short‐lived.