Evaluation of potential COVID-19 recurrence in patients with late repeat positive SARS-CoV-2 testing

Neutralizing Antibodies against SARS-CoV-2: Importance of Comorbidities in Health Personnel against Reinfections

One of the priority lines of action to contain the SARS-CoV-2 pandemic was vaccination programs for healthcare workers. However, with the emergence of highly contagious strains, such as the Omicron variant, it was necessary to know the serological status of health personnel to make decisions for the application of reinforcements. The aim of this work was to determine the seroprevalence against SARS-CoV-2 in healthcare workers in a Mexican hospital after six months of the administration of the Pfizer-BioNTech vaccine (two doses, 4 weeks apart) and to investigate the association between comorbidities, response to the vaccine, and reinfections. Neutralizing antibodies against SARS-CoV-2 were determined using ELISA assays for 262 employees of Hospital Juárez de México with and without a history of COVID-19. A beta regression analysis was performed to study the associated comorbidities and their relationship with the levels of antibodies against SARS-CoV-2. Finally, an epidemiological follow-up was carried out to detect reinfections in this population. A significant difference in SARS-CoV-2 seroprevalence was observed in workers with a history of COVID-19 prior to vaccination compared to those without a history of the disease (MD: 0.961 and SD: 0.049; <0.001). Beta regression showed that workers with a history of COVID-19 have greater protection compared to those without a history of the infection. Neutralizing antibodies were found to be decreased in alcoholic and diabetic subjects (80.1%). Notably, eight cases of Omicron reinfections were identified, and gender and obesity were associated with the presence of reinfections (6.41 OR; 95% BCa CI: 1.15, 105.0). The response to the vaccine was influenced by the history of SARS-CoV-2 infection and associated comorbidities. The above highlights the importance of prioritizing this segment of the population for reinforcements in periods of less than one year to guarantee their effectiveness against new variants.

Asymptomatic COVID-19 Reinfection in a Pediatric Patient with Heterotaxy Syndrome

We report an asymptomatic child with heterotaxy syndrome who had recurrent positive SARS-CoV-2 polymerase chain reaction testing. An aberrant lymphocyte population expressing CD19, CD16, and CD56 was identified; its phenotyping revealing atypical NK cells. This subset's role in protection from severe disease or in reinfection cannot be ascertained.

Results from a systematic programme of evaluating COVID-19 reinfection cases in the early phase of the pandemic, Singapore

OBJECTIVES

The objectives of this study were to describe the coronavirus disease caused by SARS-CoV-2 (COVID-19) reinfection evaluation algorithm used in the early phase of the pandemic in Singapore and analyze the clinical and laboratory characteristics of the cases evaluated.

METHODS

We performed a retrospective case-control analysis including all COVID-19 cases evaluated for possible reinfection under the local COVID-19 reinfection evaluation programme between 1 June 2020-30 June 2021. Whole genome sequencing (WGS) was used as confirmatory testing. We compared all reinfection ("RI") cases against those who were evaluated but eventually assessed not to be reinfection ("non-RI").

RESULTS

There were 74 possible reinfection cases evaluated through the programme, of which 32 were subsequently classified as RI. There was strong statistical evidence that RI cases had a longer interval between 1st and 2nd episode (mean 297 days; 95%-confidence interval (CI) 267-327) compared to non-RI cases (mean 186 days; 95%-CI 144-228). The cycle threshold (Ct) value of initial polymerase chain rection (PCR) at 2nd episode was also found to be significantly lower in RI cases (mean 23; 95%-CI 20-26) compared to non-RI cases (mean 34; 95%-CI 32-36). There was no significant difference in the proportion of individuals who had fever, acute respiratory symptoms or asymptomatic in both groups. Delta and beta variants were most commonly identified from WGS and provide indication of re-infection as these were not 'wild-type' and were not circulating during the time period of the index infection.

CONCLUSIONS

Using a combination of serologic, microbiologic and genomic criteria to evaluate possible reinfection cases is useful and can provide a framework for evaluation that may be modified for future similar situations.

Screening and confirmation tests for SARS-CoV-2: benefits and drawbacks

Background

Coronavirus disease 2019 is a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that emerged in late 2019 and has activated an ongoing international public health emergency. SARS-CoV-2 was discovered in Wuhan, China, in December 2019 and rapidly spread to other cities and countries. Currently, SARS-CoV-2 diagnostic tests have relied heavily on detecting viral genes, antigens, and human antibodies. Hence, this review discusses and analyses the existing screening and confirmation tests for SARS-CoV-2, including the real-time reverse transcriptase polymerase chain reaction (RT-PCR), lateral flow immunoassay (LFIA), and enzyme-linked immunosorbent assay (ELISA).

Main body

The illustrations of each testing were presented to provide the readers with an understanding of the scientific principles behind the testing methods. The comparison was made by highlighting the advantages and disadvantages of each testing. ELISA is ideal for performing the maximum population screening to determine immunological capacity, although its inability to provide reliable results on the status of the infection. Recently, LFIA has been approved as a quicker way of determining whether a patient is infected at the analysis time without using particular instruments and non-laboratory settings. RT-PCR is the gold-standard approach in terms of sensitivity and specificity.

Conclusion

However, the combination of LFIA or ELISA with RT-PCR is also proposed in this review to obtain an adequate level of sensitivity and specificity.

Graphic Abstract

Correlation between chest CT scores and clinical impact in patients re-infected with COVID-19 during the two attacks: an observational study

Background

Worldwide, millions of people got COVID-19 infection since the start of the pandemic with a large number of deaths. Re-infection with SARS-CoV-2 is possible, because it can mutate into new strains as it is an RNA virus. The main objective of our study is to correlate between CT severity score of the patients re-infected with COVID-19 during the first and second attack and its clinical impact.

Results

We performed a retrospective cohort study. It was carried out on fifty symptomatic patients (11 females and 39 males). Their ages ranged from 38 to 71 years. We included only patients who were re-infected after more than 6 months of the first infection and showed clinical symptoms with SARS-CoV-2 PCR-positive test. We found that CT severity score was decreased in the second infection in 47 (94%) of our patients associated with decreased respiratory distress as well as oxygen requirements, while the CT severity score was increased in two patients and only one patient showed no change in CT score severity between two infections.

Conclusion

The reduction in CT severity score in the majority of re-infected patients suggested the role of the immunity developed from first infection in protection against severe lung affection in case of repeated infection even after 6 months despite poor immunity against re-infection.

Risk of reinfection and disease after SARS-CoV-2 primary infection: Meta-analysis

INTRODUCTION

A precise estimate of the frequency and severity of SARS-CoV-2 reinfections would be critical to optimize restriction and vaccination policies for the hundreds of millions previously infected subjects. We performed a meta-analysis to evaluate the risk of reinfection and COVID-19 following primary infection.

METHODS

We searched MedLine, Scopus and preprint repositories for cohort studies evaluating the onset of new infections among baseline SARS-CoV-2-positive subjects. Random-effect meta-analyses of proportions were stratified by gender, exposure risk, vaccination status, viral strain, time between episodes, and reinfection definition.

RESULTS

Ninety-one studies, enrolling 15,034,624 subjects, were included. Overall, 158,478 reinfections were recorded, corresponding to a pooled rate of 0.97% (95% CI: 0.71%-1.27%), with no substantial differences by definition criteria, exposure risk or gender. Reinfection rates were still 0.66% after ≥12 months from first infection, and the risk was substantially lower among vaccinated subjects (0.32% vs. 0.74% for unvaccinated individuals). During the first 3 months of Omicron wave, the reinfection rates reached 3.31%. Overall rates of severe/lethal COVID-19 were very low (2-7 per 10,000 subjects according to definition criteria) and were not affected by strain predominance.

CONCLUSIONS

A strong natural immunity follows the primary infection and may last for more than one year, suggesting that the risk and health care needs of recovered subjects might be limited. Although the reinfection rates considerably increased during the Omicron wave, the risk of a secondary severe or lethal disease remained very low. The risk-benefit profile of multiple vaccine doses for this subset of population needs to be carefully evaluated.

Transcriptomics, Cheminformatics, and Systems Pharmacology Strategies Unveil the Potential Bioactives to Combat COVID-19

Coronavirus disease (COVID-19) is a viral disease caused by the SARS-CoV-2 virus and is becoming a global threat again because of the higher transmission rate and lack of proper therapeutics as well as the rapid mutations in the genetic pattern of SARS-CoV-2. Despite vaccinations, the prevalence and recurrence of this infection are still on the rise, which urges the identification of potential global therapeutics for a complete cure. Plant-based alternative medicine is becoming popular worldwide because of its higher efficiency and minimal side effects. Yet, identifying the potential medicinal plants and formulating a plant-based medicine is still a bottleneck. Hence, in this study, the systems pharmacology, transcriptomics, and cheminformatics approaches were employed to uncover the multi-targeted mechanisms and to screen the potential phytocompounds from significant medicinal plants to treat COVID-19. These approaches have identified 30 unique COVID-19 human immune genes targeted by the 25 phytocompounds present in four selected ethnobotanical plants. Differential and co-expression profiling and pathway enrichment analyses delineate the molecular signaling and immune functional regulations of the COVID-19 unique genes. In addition, the credibility of these compounds was analyzed by the pharmacological features. The current holistic finding is the first to explore whether the identified potential bioactives could reform into a drug candidate to treat COVID-19. Furthermore, the molecular docking analysis was employed to identify the important bioactive compounds; thus, an ultimately significant medicinal plant was also determined. However, further laboratory evaluation and clinical validation are required to determine the efficiency of a therapeutic formulation against COVID-19.

Risk of SARS-CoV-2 Reinfection 18 Months After Primary Infection: Population-Level Observational Study

Current data suggest that SARS-CoV-2 reinfections are rare. Uncertainties remain, however, on the duration of the natural immunity, its protection against Omicron variant, and on the impact of vaccination to reduce reinfection rates. In this retrospective cohort analysis of the entire population of an Italian region, we followed 1,293,941 subjects from the beginning of the pandemic to the current scenario of Omicron predominance (up to mid-February 2022). After an average of 277 days, we recorded 729 reinfections among 119,266 previously infected subjects (overall rate: 6.1‰), eight COVID-19-related hospitalizations (7/100,000), and two deaths. Importantly, the incidence of reinfection did not vary substantially over time: after 18-22 months from the primary infection, the reinfection rate was still 6.7‰, suggesting that protection conferred by natural immunity may last beyond 12 months. The risk of reinfection was significantly higher among females, unvaccinated subjects, and during the Omicron wave.

Ofeleein i mi Vlaptin-Volume II: Immunity Following Infection or mRNA Vaccination, Drug Therapies and Non-Pharmacological Management at Post-Two Years SARS-CoV-2 Pandemic

The persistence of the coronavirus disease 2019 (COVID-19) pandemic has triggered research into limiting transmission, morbidity and mortality, thus warranting a comprehensive approach to guide balanced healthcare policies with respect to people's physical and mental health. The mainstay priority during COVID-19 is to achieve widespread immunity, which could be established through natural contact or vaccination. Deep knowledge of the immune response combined with recent specific data indicates the potential inferiority of induced immunity against infection. Moreover, the prevention of transmission has been founded on general non-pharmacological measures of protection, albeit debate exists considering their efficacy and, among other issues, their socio-psychological burden. The second line of defense is engaged after infection and is supported by a plethora of studied agents, such as antibiotics, steroids and non-steroid anti-inflammatory drugs, antiviral medications and other biological agents that have been proposed, though variability in terms of benefits and adverse events has not allowed distinct solutions, albeit certain treatments might have a role in prevention and/or treatment of the disease. This narrative review summarizes the existing literature on the advantages and weaknesses of current COVID-19 management measures, thus underlining the necessity of acting based on the classical principle of "ofeleein i mi vlaptin", that is, to help or not to harm.

Monoclonal antibody therapies in the management of SARS-CoV-2 infection

Introduction

Neutralizing antibodies (NAbs) that target key domains of the spike protein in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may have therapeutic value because of their specificity. Depending on the targeted epitope, single agents may be effective, but combined treatment involving multiple NAbs may be necessary to prevent the emergence of resistant variants.

Areas covered

This article highlights the accelerated regulatory processes established to facilitate the review and approval of potential therapies. An overview of treatment approaches for SARS-CoV-2 infection, with detailed examination of the preclinical and clinical evidence supporting the use of NAbs, is provided. Finally, insights are offered into the potential benefits and challenges associated with the use of these agents.

Expert opinion

NAbs offer an effective, evidence-based therapeutic intervention during the early stages of SARS-CoV-2 infection when viral replication is the primary factor driving disease progression. As the pandemic progresses, appropriate use of NAbs will be important to minimize the risk of escape variants. Ultimately, the availability of effective treatments for COVID-19 will allow the establishment of treatment algorithms for minimizing the substantial rates of hospitalization, morbidity (including long COVID) and mortality currently associated with the disease.

Incidence of COVID-19 reinfection among Midwestern healthcare employees

Given the overwhelming worldwide rate of infection and the disappointing pace of vaccination, addressing reinfection is critical. Understanding reinfection, including longevity after natural infection, will allow us to better know the prospect of herd immunity, which hinges on the assumption that natural infection generates sufficient, protective immunity. The primary objective of this observational cohort study is to establish the incidence of reinfection of COVID-19 among healthcare employees who experienced a prior COVID-19 infection over a 10-month period. Of 2,625 participants who experienced at least one COVID-19 infection during the 10-month study period, 156 (5.94%) experienced reinfection and 540 (20.57%) experienced recurrence after prior infection. Median days were 126.50 (105.50–171.00) to reinfection and 31.50 (10.00–72.00) to recurrence. Incidence rate of COVID-19 reinfection was 0.35 cases per 1,000 person-days, with participants working in COVID-clinical and clinical units experiencing 3.77 and 3.57 times, respectively, greater risk of reinfection relative to those working in non-clinical units. Incidence rate of COVID-19 recurrence was 1.47 cases per 1,000 person-days. This study supports the consensus that COVID-19 reinfection, defined as subsequent infection ≥ 90 days after prior infection, is rare, even among a sample of healthcare workers with frequent exposure.

SARS-CoV-2 Reinfection: A Case Series from a 12-Month Longitudinal Occupational Cohort

Seven cases of COVID-19 SARS-CoV-2 reinfection from the NBA 2020-2021 occupational testing cohort are described including clinical details, antibody test results, genomic sequencing, and longitudinal RT-PCR results. Reinfections were infrequent and varied in clinical presentation, viral dynamics, and immune response.