Seroprevalence of SARS-CoV-2 antibodies in 2115 blood donors from Romania

Utility of COVID-19 Seropositive Plasma as Convalescent Plasma: An Immune and Neutralization Antibody Seroprevalence Analysis in Blood Donors for Future Potential Pandemic Readiness

OBJECTIVES

To analyze the seroprevalence of SARS-CoV-2 IgG antibodies and neutralizing antibodies in blood donors during the second wave of the pandemic and to explore the utility of COVID-19 seropositive plasma as convalescent plasma.

MATERIALS AND METHODS

In this study, 696 blood donors were tested for anti-SARS-CoV-2 IgG antibodies using a chemiluminescence assay. By blinding, 271 samples were chosen randomly for testing of neutralizing antibodies by enzyme-linked immunosorbent assay (ELISA) in duplicate among the 696 blood donors tested for anti-SARS-CoV-2 IgG antibodies, irrespective of the positivity or negativity of the result of the anti-SARS-CoV-2 IgG antibodies by chemiluminescence assay. IgG antibody levels were analyzed in signal-to-cutoff (S/Co), while neutralizing antibody levels were analyzed in percentage inhibition.

RESULTS

The seroprevalence of IgG antibodies based on the S/Co for the positive results ≥ 1.00 was 82.75%, while the seroprevalence of neutralizing antibodies based on the percentage inhibition for the positive results ≥ 30% was 89.59%. Frontline workers (FLWs) and Covishield-vaccinated individuals showed higher levels of the anti-SARS-CoV-2 IgG antibodies regarding higher S/Co. In comparison, levels of neutralization antibodies regarding percentage inhibition were higher only in FLWs. Covishield-vaccinated donors elicited a statistically higher seroprevalence of anti-SARS-CoV-2 IgG antibodies compared to the Covaxin-vaccinated, while the seroprevalence of neutralizing antibodies was not statistically different among this group. There was a positive correlation (0.762) between anti-SARS-CoV-2 IgG antibodies and neutralizing antibodies, and almost all donors' of S/Co ≥ 9.5 had neutralizing antibodies.

CONCLUSION

This study showed higher seroprevalence in the blood donor population compared to published seroprevalence in India's second wave of the pandemic. In the current study, 328 donors (47.12%) of the 696 screened donors were neither vaccinated nor had previous SARS-CoV-2 infection, but many had antibodies. The seroprevalence of neutralizing antibodies (96.42%) was higher than the seroprevalence of the anti-SARS-CoV-2 IgG antibodies (85.71%) in the donors who had previous infection of COVID-19. On the other hand, vaccinated donors showed similar immune responses for neutralizing antibodies and the anti-SARS-CoV-2 IgG antibodies. Higher IgG immune reactivity in S/Co showed a good correlation with neutralizing antibodies and can be used to screen whole blood donors for convalescent plasma donations.

Estimation of anti-SARS-CoV-2 IgG titre among blood donors in Ranchi

Introduction

Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as novel coronavirus (2019-nCoV). The disease presentation ranges from asymptomatic to severe acute respiratory failure requiring intensive care support. Anti-SARS-CoV-2 IgG antibodies are developed either by natural infection from SARS-CoV-2 or by vaccination against COVID-19. The persistence of IgG antibodies allows identification of the people who have been infected in the past, recovered from illness, and possibly become immune. 7 IgG detection and other serological assays will play an important role in research and surveillance.

Aims and Objective

The objective of the study is to assess anti-SARS-CoV-2 IgG titre among blood donors and to assess the decreasing incidence of COVID-19 in the department of blood bank, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand.

Materials and Methods

An observational, cross-sectional study was conducted at the department of blood bank, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand over a period of 2 months and 14 days from 06 February 2021 to 20 April 2021 who donated at least one unit of blood.

Results

This study recorded a greater number of male donors with B+ blood group. The anti-SARS-CoV-2 titre were mostly young adults between 18 and 31 years of age.

Conclusion

Seroprevalence was high in males having blood group B+ between 18 and 32 years of age.

SARS-CoV-2 Seroprevalence Among Whole Blood Donors During First Wave of Covid-19 Pandemic in India

The current study aimed to estimate the seroprevalence of SARS-CoV-2 IgG (S-protein) antibodies along with neutralizing assay (RBD-domain) among the whole blood donors without any prior Covid-19 history or symptoms visiting Blood Centre at a Tertiary care institution, South India amidst the ongoing pandemic. During September 2020 to March 2021, 1034 whole blood donors were enrolled into the study and were screened for anti-SARS-CoV-2 IgG antibodies using Chemiluminescence assay followed by neutralizing antibodies using surrogate neutralization ELISA. The study reported seroprevalence of 49.4%, (95% CI 46.3–52.5) among whole blood donors, with test sensitivity and specificity adjusted prevalence of 54.9% (95% CI 51.5–58.3). Seroprevalence was similar across age groups, gender, voluntary/replacement donations, area of residence, ABO and Rh groups without any statistical significance. However higher IgG antibody responses were found to be elicited in the 30–45 years age group when compared with 18–29 years age group (p value 0.046). This study also analysed the mean neutralizing capacity of SARS-CoV-2 antibodies among 97 blood donors which was 71.9 (SD: + 21.03, range 15.5 to 97.3). Donor samples with SARS-CoV-2 IgG S/Co > 9.5 had significantly higher neutralising capacity (> 68%) when compared with donor samples of S/Co < 9.5 (p value 0.000). Real-time seroprevalence studies will help to know the herd immunityamong the blood donors which will assist in knowing the Covid-19 transmission dynamics, distribution of immunity levels at a particular point in time, immunity gaps, development of novel therapeutics and prioritize the vaccination programmes to high risk individuals.

SARS-CoV-2 Seroprevalence in Western Romania, March to June 2021

Background and Objectives: The extent of SARS-CoV-2 infection among a population may be assessed by the presence of serum SARS-CoV-2 antibodies, which indicates previous exposure. The aim of this study was to determine the seroprevalence of SARS-CoV-2 infection in the adult population from Western Romania. Materials and Methods: Samples of 2443 consecutive individuals, referred for routine laboratory investigations, were tested for SARS-CoV-2 antibodies using the Elecsys immunoassay that targets the nucleocapsid protein, for identifying the presence of the total antibodies against SARS-CoV-2. Results: The overall SARS-CoV-2 seroprevalence was 45.60%. SARS-CoV-2 seroprevalence was significantly higher in age group 30-49 years (53.94%) compared to age groups 50-69 years (43.53%) and 70-91 years (30.79%) (p < 0.001, p < 0.001, respectively). No significant difference in seroprevalence was observed between females (44.83%) and males (47.05%). Conclusions: Our data revealed a high seroprevalence of SARS-CoV-2 infection in the adult population from Western Romania and indicate the rapid and significant spread of the virus. The estimated prevalence of 45.60% was 6 times higher than the rate of confirmed COVID-19 cases reported in the study area. This indicates the magnitude of virus transmission in the community.

Current challenges of severe acute respiratory syndrome coronavirus 2 seroprevalence studies among blood donors: A scoping review

BACKGROUND AND OBJECTIVES

Blood donors are increasingly being recognized as an informative resource for surveillance. We aimed to review severe acute respiratory syndrome coronavirus 2 seroprevalence studies conducted among blood donors to investigate methodological biases and provide guidance for future research.

MATERIALS AND METHODS

We conducted a scoping review of peer-reviewed and preprint publications between January 2020 and January 2021. Two reviewers used standardized forms to extract seroprevalence estimates and data on methodology pertaining to population sampling, periodicity, assay characteristics, and antibody kinetics. National data on cumulative incidence and social distancing policies were extracted from publicly available sources and summarized.

RESULTS

Thirty-three studies representing 1,323,307 blood donations from 20 countries worldwide were included (sample sizes ranged from 22 to 953,926 donations). The majority of the studies (79%) reported seroprevalence rates <10% (ranging from 0% to 76% [after adjusting for waning antibodies]). Overall, less than 1 in 5 studies reported standardized seroprevalence rates to reflect the demographics of the general population. Stratification by age and sex were most common (64% of studies), followed by region (48%). A total of 52% of studies reported seroprevalence at a single time point. Overall, 27 unique assay combinations were identified, 55% of studies used a single assay and only 39% adjusted seroprevalence rates for imperfect test characteristics. Among the nationally representative studies, case detection was most underrepresented in Kenya (1:1264).

CONCLUSION

By the end of 2020, seroprevalence rates were far from reaching herd immunity. In addition to differences in community transmission and diverse public health policies, study designs and methodology were likely contributing factors to seroprevalence heterogeneity.

The prevalence of SARS-CoV-2 antibodies in triage-negative patients and staff of a fertility setting from lockdown release throughout 2020

STUDY QUESTION

What is the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in triage-negative patients undergoing ART and fertility care providers after lockdown release and throughout 2020?

SUMMARY ANSWER

Out of the triage-negative patients whose blood samples were assessed for SARS-CoV-2 antibodies over 6 months, 5.2% yielded positive results with a significantly higher rate in health care workers (HCWs) and a significant month-by-month increase in those with evidence of antibodies.

WHAT IS KNOWN ALREADY

Patients of reproductive age are more prone to asymptomatic or minimal forms of coronavirus disease 2019 (COVID-19) as compared to older age groups, and the identification of those with active infection and those already exposed (and probably immunized) is important for safety and cost-effective use of testing resources in the fertility setting. Data on the prevalence of SARS-CoV-2 in ART patients are limited and encompass short time frames; current rates are unknown. There is also no consensus on the optimal way of screening triage-negative ART patients in moderate/high-risk areas.

STUDY DESIGN, SIZE, DURATION

A prospective longitudinal unicentric study on triage negative ART patients (n = 516) and clinical staff (n = 30) was carried out. We analyzed 705 serological tests for SARS-CoV-2 sampled between 17 May 2020 (the first working day after lockdown release) up to 1 December 2020, to assess the positivity rates for SARS-CoV-2 antibodies.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We collected data on the serological status for IgM and IgG antibodies against SARS-CoV-2 in 516 triage-negative men (n = 123) and women (n = 393) undergoing ART at a private fertility center and 30 HCWs that were at work during the study period. Antibodies were detected with a capture chemiluminescence assay (CLIA) targeting the highly Immunogenic S1 and S2 domains on the virus spike protein. We also analyzed the molecular test results of the cases exhibiting a positive serology.

MAIN RESULTS AND THE ROLE OF CHANCE

The data showed that 5.2% of the triage-negative ART patients had a positive serological result for SARS-CoV-2, with an overall conversion rate of 2.1% for IgG and 4.6% for IgM. There was no significant difference in seroprevalence between sexes. The small cohort (n = 30) of HCWs had a markedly increased seroprevalence (12.9% for Ig M and 22.6% for IgG). The highest seropositivity in our cohort was recorded in November (16.2%). The IgM positivity rates revealed significant monthly increments, paralleling official prevalence rates based on nasopharyngeal swabs. No positive molecular tests were identified in cases exhibiting a solitary positive IgG result. We show that despite a 6-fold increase in the number of ART patients with a positive serology between May and December 2020, most of our patients remain unexposed to the virus. The study was undertaken in a high-risk area for COVID-19, with a 20-times increase in the active cases across the study period.

LIMITATIONS, REASONS FOR CAUTION

The geographical restriction, alongside the lack of running a second, differently-targeted immunoassay (orthogonal testing), could limit the generalizability and translation of our results to other fertility settings or other immunoassays.

WIDER IMPLICATIONS OF THE FINDINGS

The low positivity rates for IgG against the SARS-CoV-2 spike protein seen at the end of 2020 imply that most of the fertility patients are still at risk for SARS-CoV-2 infection. Until mass vaccination and other measures effectively diminish the pandemic, risk mitigation strategies must be maintained in the fertility units in the foreseeable future. Patients with a solitary IgG+ status are most likely ‘non-infectious’ and can elude further testing without giving up the strict use of universal protective measures. With increasing seroprevalences owing to infection or vaccination, and with the consecutive increase in test performance, it is possible that serological screening of ART patients might be more cost-effective than PCR testing, especially for the many patients with repeat treatments/procedures in a time-frame of months.

STUDY FUNDING/COMPETING INTERESTS

This research received no external funding. All authors declare having no conflict of interest with regard to this trial.

Dramatic rise in seroprevalence rates of SARS-CoV-2 antibodies among healthy blood donors: The evolution of a pandemic

BACKGROUND

Seroprevalence studies of SARS-CoV-2 antibodies are useful in assessing the epidemiological status in the community, and the degree of spread.

OBJECTIVE

To study the seroprevalence rates of SARS-CoV-2 antibodies among healthy blood donors in Jordan, at various points of time and as the pandemic evolves in the community.

METHODS

In total, 1374 blood donor samples, from three groups, were tested for SARS-CoV-2 total immunoglobulin antibodies. In the first group, samples from 734 individuals (from donations made between January and June 2020) were tested in June. In the second group, 348 individuals were tested in September 2020. The third group of 292 individuals was tested in February 2021. A qualitative assay was used for testing (specificity 99.8%, sensitivity 100%).

RESULTS

The first two groups, from January-June and September 2020, when confirmed Covid-19 cases numbered between several hundred and 3000, showed a seroprevalence rate of 0% (95% CI 0.00-0.51%). The third group (early February 2021), when the number of confirmed cases had reached 100 times that of September 2020, revealed a seroprevalence of 27.4% (95% CI 22.5-32.9%).

CONCLUSIONS

A dramatic rise in seroprevalence of SARS-CoV-2 antibodies was seen among healthy blood donors in Jordan, in parallel with widespread intracommunity transmission of the disease. This information is useful for assessing the degree of herd immunity, and provides for better understanding of the pandemic.

Dramatic rise in seroprevalence rates of SARS-CoV-2 antibodies among healthy blood donors: The evolution of a pandemic

BACKGROUND

Seroprevalence studies of SARS-CoV-2 antibodies are useful in assessing the epidemiological status in the community, and the degree of spread.

OBJECTIVE

To study the seroprevalence rates of SARS-CoV-2 antibodies among healthy blood donors in Jordan, at various points of time and as the pandemic evolves in the community.

METHODS

In total, 1374 blood donor samples, from three groups, were tested for SARS-CoV-2 total immunoglobulin antibodies. In the first group, samples from 734 individuals (from donations made between January and June 2020) were tested in June. In the second group, 348 individuals were tested in September 2020. The third group of 292 individuals was tested in February 2021. A qualitative assay was used for testing (specificity 99.8%, sensitivity 100%).

RESULTS

The first two groups, from January-June and September 2020, when confirmed Covid-19 cases numbered between several hundred and 3000, showed a seroprevalence rate of 0% (95% CI 0.00-0.51%). The third group (early February 2021), when the number of confirmed cases had reached 100 times that of September 2020, revealed a seroprevalence of 27.4% (95% CI 22.5-32.9%).

CONCLUSIONS

A dramatic rise in seroprevalence of SARS-CoV-2 antibodies was seen among healthy blood donors in Jordan, in parallel with widespread intracommunity transmission of the disease. This information is useful for assessing the degree of herd immunity, and provides for better understanding of the pandemic.