Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibodies in Egyptian Convalescent Plasma Donors

Role of research Laboratories in pandemic and epidemic response in the Eastern Mediterranean Region: Experiences from COVID-19, avian influenza, and MERS-CoV

We share the experience of research laboratories in the Eastern Mediterranean Region (EMR) that contributed to preparedness and response to highly pathogenic avian influenza (HPAI), Middle-East respiratory syndrome coronavirus (MERS-CoV), and coronavirus disease (COVID-19). Research groups in the region were pivotal in identifying, characterizing the pathogens and describing their evolution, distribution, transmission routes, and the immunological profile of exposed populations. They demonstrated the capacity to develop and test antivirals and potential vaccines. The EMR experience is a model of how national systems can work with researchers to improve regional preparedness and response to future epidemics and pandemics.

Determining the SARS-CoV-2 Anti-Spike Cutoff Level Denoting Neutralizing Activity Using Two Commercial Kits

BACKGROUND

The viral neutralization assay is the gold standard to estimate the level of immunity against SARS-CoV-2. This study analyzes the correlation between the quantitative Anti-SARS-CoV-2 QuantiVac ELISA (IgG) and the NeutraLISA neutralization assay.

METHODS

650 serum samples were tested for both SARS-CoV-2 anti-spike (anti-S) immunoglobulin G (IgG) and neutralizing antibodies (nAbs) using kits by EUROIMMUN, Germany.

RESULTS

There was a significant correlation between levels of anti-S and nAbs (Spearman's rho = 0.913). Among the positive samples for anti-S, 77.0% (n = 345) were positive for nAbs. There was a substantial agreement between anti-S and nAbs (Cohen's kappa coefficient = 0.658; agreement of 83.38%). Considering NeutraLISA as a gold standard, anti-S had a sensitivity of 98.57%, specificity of 65.66%, NPV of 97.5%, and PPV of 77.0%. When the anti-S titer was greater than 18.1 RU/mL (57.9 BAU/mL), nAbs were positive, with a sensitivity of 90.0% and specificity of 91%.

CONCLUSIONS

A titer of SARS-CoV-2 anti-S IgG can be correlated with levels of nAbs.

The utility of grey zone testing in improving blood safety

OBJECT

Transfusion-transmitted infections threaten blood safety. The management of samples with weak reactivity is confusing. Our study aimed to investigate the utility of grey zone (GZ) testing in the screening of the hepatitis B virus (HBV), the hepatitis C virus (HCV), and the human immunodeficiency virus (HIV).

METHODS

Chemiluminescence assays (CLA) were used for the blood screening. For each infectious marker, two CLA kits were used, but for each sample, only one kit was used for each infectious marker. An S/CO ≥ 8.0 was considered reactive, and an S/CO < 0.8 was considered non-reactive. A 0.8 ≤ S/CO < 1.0 was set as GZ1, a 1.0, ≤ S/CO < 4.0 was set as GZ2, and a 4.0 ≤ S/CO < 8.0 was set as GZ3. The samples located at different GZs were separately verified using nucleic acid testing (NAT).

RESULTS

22,081 patients requiring blood transfusions were included in this study. The cohort had an average age of 32.6 ± 10.6 years old. HBV test kit B (0.41% reactivity and 0.58% GZ rate) was more sensitive than kit A (0.28% reactivity and 0.43% GZ rate). HCV test kit A (0.29% reactivity and 0.57% GZ rate) was more sensitive than kit B (0.27% reactivity and 0.31% GZ rate). HIV test kit A (0.10% reactivity and 0.20% GZ rate) was more sensitive than kit B (0.08% reactivity and 0.11% GZ rate). All the samples in GZ1 were negative for NAT. HBV test kit A has negativities of 20.00% and 4.35% in GZ2 and GZ3, respectively, while HBV test kit B has negativities of 36.84% and 35.48% in GZ2 and GZ3, respectively. HCV test kit A has negativities of 100.00% and 66.67% in GZ2 and GZ3, respectively, while HCV test kit B has negativities of 72.73% and 27.78% in GZ2 and GZ3, respectively. HIV test kit A has negativities of 100.00% and 88.24% in GZ2 and GZ3, respectively, while HCV test kit B has negativities of 100.00% and 50.00% in GZ2 and GZ3, respectively.

CONCLUSION

The GZ is useful in blood screening for HBV, HCV, and HIV. A test kit with a high sensitivity has a low specificity. Different test kits should be set with different GZs based on their sensitivity and specificity.

Passive Immunity Should and Will Work for COVID-19 for Some Patients

In the absence of effective antiviral chemotherapy and still in the context of emerging vaccines for severe acute respiratory syndrome-CoV-2 infections, passive immunotherapy remains a key treatment and possible prevention strategy. What might initially be conceived as a simplified donor-recipient process, the intricacies of donor plasma, IV immunoglobulins, and monoclonal antibody modality applications are becoming more apparent. Key targets of such treatment have largely focused on virus neutralization and the specific viral components of the attachment Spike protein and its constituents (e.g., receptor binding domain, N-terminal domain). The cumulative laboratory and clinical experience suggests that beneficial protective and treatment outcomes are possible. Both a dose- and a time-dependency emerge. Lesser understood are the concepts of bioavailability and distribution. Apart from direct antigen binding from protective immunoglobulins, antibody effector functions have potential roles in outcome. In attempting to mimic the natural but variable response to infection or vaccination, a strong functional polyclonal approach attracts the potential benefits of attacking antigen diversity, high antibody avidity, antibody persistence, and protection against escape viral mutation. The availability and ease of administration for any passive immunotherapy product must be considered in the current climate of need. There is never a perfect product, but yet there is considerable room for improving patient outcomes. Given the variability of human genetics, immunity, and disease, and given the nuances of the virus and its potential for change, passive immunotherapy can be developed that will be effective for some but not all patients. An understanding of such patient variability and limitations is just as important as the understanding of the direct interactions between immunotherapy and virus.

The predictors of high titer of anti-SARS-CoV-2 antibody of convalescent plasma donors

Background

Recent evidence suggested that the higher titers of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody from convalescent plasma donors contributed to the clinical improvement in coronavirus disease 2019 (COVID-19) patients. However, the titers of anti-SARS-CoV-2 antibodies varied in each individual, and the precise factors that might govern such variation have not been elucidated.

Objectives

To assess the factors associated with high titers of anti-SARS-CoV-2 antibody among COVID-19 convalescent plasma (CCP) donors.

Methods

A cross-sectional study was conducted in Saiful Anwar General Hospital, Malang, Indonesia. Information of interest including demographic characteristics, clinical symptoms, comorbidities, laboratory findings, and the titers of anti-SARS-CoV-2 antibody among COVID-19 CCP donors were collected. The correlation was assessed using multiple logistic regression.

Results

A total of 50 COVID-19 CCP donors with the titers of anti-SARS-CoV-2 antibody of more than 1:320 and 33 donors with the titers of less than 1:320 were analyzed. Our analysis revealed that CCP donors with history of cough, fever, dyspnea, and pneumonia significantly had higher titers of anti-SARS-CoV-2 antibody compared to asymptomatic donors. Moreover, CCP donors with elevated levels of eosinophils and immature granulocytes and low levels of albumins had higher levels of anti-SARS-CoV-2 antibody. The titer of antibody was not affected by comorbidities of donors.

Conclusions

CPP donors who had experience of symptomatic COVID-19 with high eosinophils level, high immature granulocytes and low albumin level have higher titers of anti-SARS-COV-2 antibody than those who experienced asymptomatic COVID-19. Our current findings may be used as the additional baseline criteria for selecting the donors of CCP for the management of COVID-19.

Immunogenicity and Safety of an Inactivated SARS-CoV-2 Vaccine: Preclinical Studies

Since the emergence of SARS-CoV-2 at the end of 2019, 64 candidate vaccines are in clinical development and 173 are in the pre-clinical phase. Five types of vaccines are currently approved for emergency use in many countries (Inactivated, Sinopharm; Viral-vector, Astrazeneca, and Gamaleya Research Institute; mRNA, Moderna, and BioNTech/Pfizer). The main challenge in this pandemic was the availability to produce an effective vaccine to be distributed to the world's population in a short time. Herein, we developed a whole virus NRC-VACC-01 inactivated candidate SARS-CoV-2 vaccine and tested its safety and immunogenicity in laboratory animals. In the preclinical studies, we used four experimental animals (mice, rats, guinea pigs, and hamsters). Antibodies were detected as of week three post vaccination and continued up to week ten in the four experimental models. Safety evaluation of NRC-VACC-01 inactivated candidate vaccine in rats revealed that the vaccine was highly tolerable. By studying the effect of booster dose in the immunological profile of vaccinated mice, we observed an increase in neutralizing antibody titers after the booster shot, thus a booster dose was highly recommended after week three or four. Challenge infection of hamsters showed that the vaccinated group had lower morbidity and shedding than the control group. A phase I clinical trial will be performed to assess safety in human subjects.