Repeated SARS-CoV-2 Positivity: Analysis of 123 Cases

Clinical characteristics associated with recurrent viral RNA positivity in patients within two weeks after recovering from the first SARS-CoV-2 infection

Many studies have shown that recovered coronavirus disease 2019 (COVID-19) patients frequently exhibit recurrent viral RNA positivity (RP) for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our study aimed to summarize the clinical characteristics of these patients and explore potential reasons for RP occurrence. We divided 439 participants into four groups based on the severity of illness prior to the COVID-19 recovery and age: mild-child group, moderate-child group, mild-adult group, and moderate-adult group. Laboratory data were collected and statistical analyzed using the SPSS software, version 24.0. Significant differences were observed in age, alanine aminotransferase (ALT), aspartate aminotransferase (AST), C-reactive protein (CRP), interleukin 6 (IL-6), and neutrophil to lymphocyte ratio (NLR) levels between the mild-adult group and the moderate-adult group (P < 0.05). Additionally, AST levels differed significantly between the mild-child group and the moderate-child group (P < 0.05). The proportion of RP patients within the four groups varied from 7.95% to 26.13% within a 2-week period. Logistic regression analysis revealed that younger age and moderate symptoms were risk factors for RP in children, while the presence of comorbidities (such as chronic heart, lung, liver, and kidney diseases), elevated IL-6 levels, and NLR were risk factors for RP in adults. We constructed two predictive models containing these relevant parameters, and the results of the receiver operating characteristic (ROC) curves indicated strong predictive utility. Our findings suggest that younger children with more severe symptoms, as well as adult patients with elevated levels of IL-6 and NLR and underlying diseases, are at higher risk of RP occurrence.

Prior SARS-CoV-2 infection may not alter the clinical course of COVID-19 in lung transplant recipients: A single-center experience

BACKGROUND

In the general population, prior infection with SARS-CoV-2 reduces the risk of severe COVID-19; however, studies in lung transplant recipients (LTRs) are lacking. We sought to describe the clinical course of COVID-19 recurrence and compare outcomes between the first and second episodes of COVID-19 in LTRs.

METHODS

We conducted a retrospective, single-center cohort study of LTRs with COVID-19 between January 1, 2022, and September 30, 2022, during the Omicron wave. We compared the clinical course of a second episode of COVID-19 to that of the patients' own first episode and to that of LTRs who developed a first episode during the study period.

RESULTS

During the study period, we identified 24 LTRs with COVID-19 recurrence and another 75 LTRs with a first episode of COVID-19. LTRs who survived the initial episode of COVID-19 had a similar disease course with recurrence, with a trend toward reduced hospitalization (10 (41.6%) vs. 4 (16.7%), p = .114). Furthermore, compared to LTRs with a primary infection during the Omicron wave, those with a reinfection had a non-statistically significant trend toward reduced hospitalizations (aOR .391, 95% CI [.115-1.321], p = .131), shorter lengths-of-stay (median, 4 vs. 9 days, p = .181), and reduced intensive care unit admissions, intubations, and COVID-19-related mortality.

CONCLUSIONS

LTRs who survive the first episode of COVID-19 are likely to have a similar clinical course with recurrent episodes. Although recurrent COVID-19 may be milder, larger, well-powered studies are needed to confirm this observation. Ongoing precautions are warranted.

Predictors of SARS-CoV-2 Infection and Severe and Lethal COVID-19 after Three Years of Follow-Up: A Population-Wide Study

In this cohort study, the general population of an Italian Province was followed for three years after the start of the pandemic, in order to identify the predictors of SARS-CoV-2 infection and severe or lethal COVID-19. All the National Healthcare System information on biographical records, vaccinations, SARS-CoV-2 swabs, COVID-19 cases, hospitalizations and co-pay exemptions were extracted from 25 February 2020 to 15 February 2023. Cox proportional hazard analysis was used to compute the relative hazards of infection and severe or lethal COVID-19, adjusting for age, gender, vaccine status, hypertension, diabetes, major cardiovascular diseases (CVD), chronic obstructive pulmonary disease (COPD), kidney disease or cancer. Among the 300,079 residents or domiciled citizens, 41.5% had ≥1 positive swabs during the follow-up (which lasted a mean of 932 days). A total of 3.67% of the infected individuals experienced severe COVID-19 (n = 4574) and 1.76% died (n = 2190). Females, the elderly and subjects with diabetes, CVD, COPD, kidney disease and cancer showed a significantly higher risk of SARS-CoV-2 infection. The likelihood of severe or lethal COVID-19 was >90% lower among the youngest, and all comorbidities were independently associated with a higher risk (ranging from +28% to +214%) of both outcomes. Two years after the start of the immunization campaign, the individuals who received ≥2 doses of COVID-19 vaccines still showed a significantly lower likelihood of severe or lethal disease, with the lowest risk observed among subjects who received at least one booster dose.

Epitope Coverage of Anti-SARS-CoV-2 Nucleocapsid IgA and IgG Antibodies Correlates with Protection against Re-Infection by New Variants in Subsequent Waves of the COVID-19 Pandemic

The COVID-19 pandemic continues to affect individuals across the globe, with some individuals experiencing more severe disease than others. The relatively high frequency of re-infections and breakthrough infections observed with SARS-CoV-2 highlights the importance of extending our understanding of immunity to COVID-19. Here, we aim to shed light on the importance of antibody titres and epitope utilization in protection from re-infection. Health care workers are highly exposed to SARS-CoV-2 and are therefore also more likely to become re-infected. We utilized quantitative, multi-antigen, multi-epitope SARS-CoV-2 protein microarrays to measure IgG and IgA titres against various domains of the nucleocapsid and spike proteins. Potential re-infections in a large, diverse health care worker cohort (N = 300) during the second wave of the pandemic were identified by assessing the IgG anti-N titres before and after the second wave. We assessed epitope coverage and antibody titres between the 'single infection' and 're-infection' groups. Clear differences were observed in the breadth of the anti-N response before the second wave, with the epitope coverage for both IgG (p = 0.019) and IgA (p = 0.015) being significantly increased in those who did not become re-infected compared to those who did. Additionally, the IgG anti-N (p = 0.004) and anti-S titres (p = 0.018) were significantly higher in those not re-infected. These results highlight the importance of the breadth of elicited antibody epitope coverage following natural infection in protection from re-infection and disease in the COVID-19 pandemic.

The machine learning model based on trajectory analysis of ribonucleic acid test results predicts the necessity of quarantine in recurrently positive patients with SARS-CoV-2 infection

Background

SARS-CoV-2 patients re-experiencing positive nucleic acid test results after recovery is a concerning phenomenon. Current pandemic prevention strategy demands the quarantine of all recurrently positive patients. This study provided evidence on whether quarantine is required in those patients, and predictive algorithms to detect subjects with infectious possibility.

Methods

This observational study recruited recurrently positive patients who were admitted to our shelter hospital between May 12 and June 10, 2022. The demographic and epidemiologic data was collected, and nucleic acid tests were performed daily. virus isolation was done in randomly selected cases. The group-based trajectory model was developed based on the cycle threshold (Ct) value variations. Machine learning models were validated for prediction accuracy.

Results

Among the 494 subjects, 72.04% were asymptomatic, and 23.08% had a Ct value under 30 at recurrence. Two trajectories were identified with either rapid (92.24%) or delayed (7.76%) recovery of Ct values. The latter had significantly higher incidence of comorbidities; lower Ct value at recurrence; more persistent cough; and more frequently reported close contacts infection compared with those recovered rapidly. However, negative virus isolation was reported in all selected samples. Our predictive model can efficiently discriminate those with delayed Ct value recovery and infectious potentials.

Conclusion

Quarantine seems to be unnecessary for the majority of re-positive patients who may have low transmission risks. Our predictive algorithm can screen out the suspiciously infectious individuals for quarantine. These findings may assist the enaction of SARS-CoV-2 pandemic prevention strategies regarding recurrently positive patients in the future.

The effects of COVID-19 infection on the mortality of patients receiving rituximab therapy

BACKGROUND

Rituximab (RTX) is an important immunosuppressive agent used for many rheumatologic diseases. This study investigated the factors affecting mortality and mortality due to COVID-19 infection in patients receiving RTX.

METHODS

From March 2020 to November 2021, 111 patients who were followed up at a tertiary center with a diagnosis of any rheumatologic disease and who were diagnosed with COVID-19 were enrolled out of 336 patients who received at least one dose of RTX. Age, COVID-19 vaccination status, comorbidities, and some laboratory parameters were determined. The association between them and COVID-19 infection was investigated. In addition, patients were divided into two groups: those with rheumatoid arthritis (RA) and those without RA, and factors affecting mortality were studied.

RESULTS

Thirty (27.0%) of the total 111 patients treated with RTX who tested positive for COVID-19 died. Among these patients, 19 (32.7%) of 58 patients diagnosed with RA died. Of the 53 patients diagnosed with non RA disease, 11 (20.7%) died. Age (p = 0.003, OR: 1.058, 95% CI: 1.025-1.097) and age at diagnosis (p = 0.047, OR: 1.032, 95% CI: 1.000-1.064) were the lowest against COVID-19 infection. Rate of vaccination of at least two doses (p = 0.000, OR: 0.170, 95% CI: 0.065-0.491), number of comorbid conditions (p = 0.001, OR: 1.530, 95% CI: 1.202-1.949), CKD (p = 0.003, significance was found between OR: 7.000, 95% CI: 1.926-25.439) and DM (p = 0.000, OR: 6.978, 95% CI: 2.499-19.483) and death.

CONCLUSION

As a result of the study, it was found that RTX treatment in particular increased the risk of death from COVID-19 infection. However, vaccination against COVID-19 has a very important place in this patient group. It is important that vaccination is administered at the full dose and adjusted according to the RTX treatment time, and that the dose and timing of RTX treatment are regulated.

Milder symptoms and shorter course in patients with re-positive COVID-19: A cohort of 180 patients from Northeast China

China experienced another widespread Coronavirus disease 2019 (COVID-19) outbreak recently caused by the Omicron variant, which is less severe but far more contagious than the other COVID-19 variants, leading local governments to focus efforts on eliminating the spread of the disease. Previous studies showed that after “recovering” from the virus, some patients could re-test positive for COVID-19 with nucleic acid tests, challenging the control of disease spread. In this study, we aimed to analyze the clinical and laboratory characteristics of re-positive COVID-19 patients in Northeast China. We retrospectively analyzed data from confirmed reverse transcription polymerase chain reaction (RT-PCR) re-positive COVID-19 patients who were admitted to the First Hospital of Jilin University, Jilin Province, China, from March to June 2022. Detailed clinical symptoms, medical history, anti-Corona Virus (CoV) IgG and IgM levels, and CoV nucleic acid cycle threshold (Ct) values during the re-positive period were collected and analyzed. A total of 180 patients were included in this study, including 62 asymptomatic cases and 118 mild cases. The cohort included 113 men and 67 women, with an average age of 45.73 years. The median time between recovery from the virus and re-positivity was 13 days. Our results showed that the proportion of re-positive patients with symptoms was lower, and the nucleic acid test-positive duration was shorter during the re-positive period. Furthermore, in patients with underlying disease, the proportion of patients with symptoms was higher, anti-CoV IgG levels were lower, and the total disease duration was longer. In conclusion, during the re-positive period, the symptoms were milder, and the CoV nucleic acid test-positive course was shorter. The concomitant underlying disease is an important factor associated with clinical symptoms, and the overall course of COVID-19 re-positive patients may be associated with lower anti-CoV IgG levels. Large-scale and multicenter studies are recommended to better understand the pathophysiology of recurrence in patients with COVID-19.

SARS-CoV-2 reinfections during the first three major COVID-19 waves in Bulgaria

BACKGROUND

The COVID-19 pandemic has had a devastating impact on the world over the past two years (2020-2021). One of the key questions about its future trajectory is the protection from subsequent infections and disease conferred by a previous infection, as the SARS-CoV-2 virus belongs to the coronaviruses, a group of viruses the members of which are known for their ability to reinfect convalescent individuals. Bulgaria, with high rates of previous infections combined with low vaccination rates and an elderly population, presents a somewhat unique context to study this question.

METHODS

We use detailed governmental data on registered COVID-19 cases to evaluate the incidence and outcomes of COVID-19 reinfections in Bulgaria in the period between March 2020 and early December 2021.

RESULTS

For the period analyzed, a total of 4,106 cases of individuals infected more than once were observed, including 31 cases of three infections and one of four infections. The number of reinfections increased dramatically during the Delta variant-driven wave of the pandemic towards the end of 2021. We observe a moderate reduction of severe outcomes (hospitalization and death) in reinfections relative to primary infections, and a more substantial reduction of severe outcomes in breakthrough infections in vaccinated individuals.

CONCLUSIONS

In the available datasets from Bulgaria, prior infection appears to provide some protection from severe outcomes, but to a lower degree than the reduction in severity of breakthrough infections in the vaccinated compared to primary infections in the unvaccinated.

The prevalence of adaptive immunity to COVID-19 and reinfection after recovery - a comprehensive systematic review and meta-analysis

This study aims to estimate the prevalence and longevity of detectable SARS-CoV-2 antibodies and T and B memory cells after recovery. In addition, the prevalence of COVID-19 reinfection and the preventive efficacy of previous infection with SARS-CoV-2 were investigated. A synthesis of existing research was conducted. The Cochrane Library, the China Academic Journals Full Text Database, PubMed, and Scopus, and preprint servers were searched for studies conducted between 1 January 2020 to 1 April 2021. Included studies were assessed for methodological quality and pooled estimates of relevant outcomes were obtained in a meta-analysis using a bias adjusted synthesis method. Proportions were synthesized with the Freeman-Tukey double arcsine transformation and binary outcomes using the odds ratio (OR). Heterogeneity was assessed using the I² and Cochran's Q statistics and publication bias was assessed using Doi plots. Fifty-four studies from 18 countries, with around 12,000,000 individuals, followed up to 8 months after recovery, were included. At 6-8 months after recovery, the prevalence of SARS-CoV-2 specific immunological memory remained high; IgG - 90.4% (95%CI 72.2-99.9, I² = 89.0%), CD4+ - 91.7% (95%CI 78.2-97.1y), and memory B cells 80.6% (95%CI 65.0-90.2) and the pooled prevalence of reinfection was 0.2% (95%CI 0.0-0.7, I² = 98.8). Individuals previously infected with SARS-CoV-2 had an 81% reduction in odds of a reinfection (OR 0.19, 95% CI 0.1-0.3, I² = 90.5%). Around 90% of recovered individuals had evidence of immunological memory to SARS-CoV-2, at 6-8 months after recovery and had a low risk of reinfection.RegistrationPROSPERO: CRD42020201234.

Screening the hub genes and analyzing the mechanisms in discharged COVID-19 patients retesting positive through bioinformatics analysis

BACKGROUND

After encountering COVID-19 patients who test positive again after discharge, our study analyzed the pathogenesis to further assess the risk and possibility of virus reactivation.

METHODS

A separate microarray was acquired from the Gene Expression Omnibus (GEO), and its samples were divided into two groups: a "convalescent-RTP" group consisting of convalescent and "retesting positive" (RTP) patients (group CR) and a "healthy-RTP" group consisting of healthy control and RTP patients (group HR). The enrichment analysis was performed with R software, obtaining the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, the protein-protein interaction (PPI) networks of each group were established, and the hub genes were discovered using the cytoHubba plugin.

RESULTS

In this study, 6622 differentially expressed genes were identified in the group CR, among which RAB11B-AS1, DISP1, MICAL3, PSMG1, and DOCK4 were up-regulated genes, and ANAPC1, IGLV1-40, SORT1, PLPPR2, and ATP1A1-AS1 were down-regulated. 7335 genes were screened in the group HR, including the top 5 up-regulated genes ALKBH6, AMBRA1, MIR1249, TRAV18, and LRRC69, and the top 5 down-regulated genes FAM241B, AC018529.3, AL031963.3, AC006946.1, and FAM149B1. The GO and KEGG analysis of the two groups revealed a significant enrichment in immune response and apoptosis. In the PPI network constructed, group CR and group HR identified 10 genes, respectively, and TP53BP1, SNRPD1, and SNRPD2 were selected as hub genes.

CONCLUSIONS

Using the messenger ribonucleic acid (mRNA) expression data from GSE166253, we found TP53BP1, SNRPD1, and SNRPD2 as hub genes in RTP patients, which is vital to the management and prognostic prediction of RTP patients.

Clinical Characteristics in Patients with Redetected Positive RNA Test After Recovery from Foreign-Imported COVID-19 Cases in Xi’an, China

Purpose

At present, it has been found that managing patients with a redetected positive RNA test after recovery from foreign-imported coronavirus disease 2019 (COVID-19) cases in China is challenging. The purpose of the current study was to describe the clinical characteristics of these patients.

Methods

This retrospective cohort study included 137 COVID-19 patients who were discharged from the Xi’an Public Health Center from 28 July 2020 to 31 December 2021. We compared the clinical characteristics between positive retest patients and non-positive retest patients.

Results

137 COVID-19 patients entered our study, 27 (19.7%) cases of COVID-19 with a redetected positive RNA test by the end of the follow-up period. Fever [(n = 31 (22.6%)], cough [n = 26 (18.9%)] and sore throat [n = 20 (14.5%)] were the most common initial symptoms among the foreign-imported COVID-19 patients, and there were almost no significant differences in initial symptoms between positive retest patients and non-positive retest patients. The positive retest patients had a higher lymphocyte count (p = 0.031) and lymphocyte percentage (p = 0.007) during readmission. There were generally no significant differences in other routine blood test findings, IgG and IgM antibody responses, between positive retest patients and non-positive retest patients, or in positive retest patients over time (before, during, or after positive patient detection). After readmission, positive retest patients displayed fewer symptoms or no obvious disease progression and more sustained remission by CT imaging.

Conclusion

Our findings revealed that the clinical characteristics at the time of initial diagnosis were not closely related to redetected positive RNA tests after recovery from foreign-imported COVID-19 cases. Positive retest patients had virtually no symptoms and displayed no obvious disease progression during readmission. These findings provide important information and clinical evidence for the effective management of foreign-imported COVID-19 patients during their convalescent phase.

Clinical Characteristics and Outcomes of Patients with SARS-CoV-2 Reinfection

Objective

To examine the clinical characteristics, risk of hospitalization and mortality of patients diagnosed with SARS-CoV-2 reinfection.

Patients and Methods

We retrospectively reviewed all patients with SARS-CoV-2 reinfection all Mayo Clinic sites between May 23, 2020, and June 30, 2021 (the period before emergence of delta variant in United States). The reinfection was defined as positive SARS-CoV-2 test ≥ 90 days after initial infection or 45-89 days after with symptomatic second episode. Vaccination status was classified as fully vaccinated, first dose and unvaccinated. Comparative analysis of baseline characteristics and comorbidities was performed by hospitalization and vaccination status. The survival analysis of hospitalized patients was performed using cox-proportional hazard regression.

Results

Among 554 reinfected patients, 59 (10.6%) were pediatric, and 495 (89.4%) were adults. The median age was 13.9 years (interquartile range [IQR], 8.5-16.5) for pediatric and 50.2 years (IQR, 28.4-65.6) for adult population. Among adult patients, majority were unvaccinated (83.4%, n=413) and duration to reinfection from initial infection was longest in fully vaccinated group (p < .001). 42 (75%) out of 56 patients were seropositive within seven days of reinfection. In hospitalized adult patients, Charlson Comorbidity Index (CCI) was an independent risk factor for mortality (adjusted hazard ratio [aHR], 0.35; 95% CI, 0.19 to 0.51).

Conclusion

In this study, majority of adult patients with SARS-CoV-2 reinfection were unvaccinated. Furthermore, the duration to reinfection was longest in fully vaccinated individuals. Seropositivity was common among adult patients.

Evidence of SARS-CoV-2 symptomatic reinfection in four healthcare professionals from the same hospital despite the presence of antibodies

OBJECTIVES

Since the onset of the COVID-19 pandemic, cases of reinfection with SARS-CoV-2 have been reported, raising additional public health concerns. SARS-CoV-2 reinfection was assessed in healthcare workers (HCWs) in Tunisia because they are at the greatest exposure to infection by different variants.

METHODS

We conducted whole-genome sequencing of the viral RNA from clinical specimens collected during the initial infection and the suspected reinfection from 4 HCWs, who were working at the Habib Bourguiba University Hospital (Sfax, Tunisia) and retested positive for SARS-CoV-2 through reverse transcriptase-polymerase chain reaction (RT-PCR) after recovery from a first infection. A total of 8 viral RNAs from the patients' respiratory specimens were obtained, which allowed us to characterize the differences between viral genomes from initial infection and positive retest. The serology status for total Ig, IgG, and IgM against SARS-CoV-2 was also determined and followed after the first infection.

RESULTS

We confirmed through whole-genome sequencing of the viral samples that all 4 cases experienced a reinfection event. The interval between the 2 infection events ranged between 45 and 141 days, and symptoms were milder in the second infection for 2 patients and more severe for the remaining 2 patients. Reinfection occurred in all 4 patients despite the presence of antibodies in 3 of them.

CONCLUSION

This study adds to the rapidly growing evidence of COVID-19 reinfection, where viral sequences were used to confirm infection by distinct isolates of SARS-CoV-2 in HCWs. These findings suggest that individuals who are exposed to different SARS-CoV-2 variants might not acquire sufficiently protective immunity through natural infection and emphasize the necessity of their vaccination and the regular follow-up of their immune status both in quantitative and qualitative terms.

Reinfection by SARS CoV2 in Valle Del Cauca, Colombia: A Descriptive Retrospective Study

Introduction: In coronavirus cases, reinfection has been associated with short-term immunity and genetic changes in viruses which allow them to escape from immune response, viral genotyping is required to make the precise diagnosis of reinfection, but the suspicion occurs in patients with more than 90 days between the tests and total improvement between them. We made a descriptive retrospective study with the cases of reinfection in Valle del Cauca, Colombia. Results: We found up to June 30, 3249 cases with suspected reinfection, 1.1% of all cases. During the first infection episode, 68% of the patients had symptoms, while at the moment of reinfection, the percentage was 73.4%. 55% of the analyzed cases had symptoms in both infection episodes, hospitalization of reinfection cases was 2% during the first episode and 2.2% in the second one. Conclusion: the reinfection percentage was low, as well as the hospitalization and ICU cases. These results allow to define that in terms of the provision of healthcare services, reinfection defined in this study, does not generate any differences in care required vs the first episode.

Recurrent COVID-19 infection in a case of rituximab-induced hypogammaglobulinaemia

Patients with immunodeficiency are at an increased risk of recurrent COVID-19 infection. They may lack the natural immune response that usually confers long-lasting immunity. Here, we present our experience managing one such patient, who had a COVID-19 infection twice, 5 months apart. He had a positive SARS-CoV-2 real-time reverse transcription polymerase chain reaction (RT-PCR) and computed tomography (CT) thorax with classical findings of COVID-19 on both occasions. He had multiple negative RT-PCR tests and two CT scans without COVID-19 features between these two infections. While the antibody response to the first infection was not detectable, the response to the second infection was robust. Live attenuated vaccines are contraindicated in patients with immunodeficiency, and other vaccines may not elicit an adequate immune response. A high index of suspicion for recurrent COVID-19 is warranted in this group of patients.

An update on host immunity correlates and prospects of re-infection in COVID-19

Reinfection with SARS-CoV-2 is not frequent yet the incidence rate of it is increasing globally owing to the slow emergence of drift variants that pose a perpetual threat to vaccination strategies and have a greater propensity for disease reoccurrence. Long-term protection against SARS-CoV-2 reinfection relies on the induction of the innate as well as the adaptive immune response endowed with immune memory. However, a multitude of factors including the selection pressure, the waning immunity against SARS-CoV-2 over the first year after infection possibly favors evolution of more infectious immune escape variants, amplifying the risk of reinfection. Additionally, the correlates of immune protection, the novel SARS-CoV-2 variants of concern (VOC), the durability of the adaptive and mucosal immunity remain major challenges for the development of therapeutic and prophylactic interventions. Interestingly, a recent body of evidence indicated that the gastrointestinal (GI) tract is another important target organ for SARS-CoV-2 besides the respiratory system, potentially increasing the likelihood of reinfection by impacting the microbiome and the immune response via the gut-lung axis. In this review, we summarized the latest development in SARS-CoV-2 reinfection, and explored the untapped potential of trained immunity. We also highlighted the immune memory kinetics of the humoral and cell-mediated immune response, genetic drift of the emerging viral variants, and discussed the current challenges in vaccine development. Understanding the dynamics and the quality of immune response by unlocking the power of the innate, humoral and cell-mediated immunity during SARS-CoV-2 reinfection would open newer avenues for drug discovery and vaccine designs.

The mystery of COVID-19 reinfections: A global systematic review and meta-analysis

BACKGROUND

As the COVID-19 pandemic rages on, reports on disparities in vaccine roll out alongside COVID-19 reinfection have been emerging. We conducted a systematic review to assess the determinants and disease spectrum of COVID-19 reinfection.

MATERIALS AND METHODS

A comprehensive search covering relevant databases was conducted for observational studies reporting Polymerase Chain Reaction (PCR) confirmed infection and reinfection cases. A quality assessment tool developed by the National Institute of Health (NIH) for the assessment of case series was utilized. Meta-analyses were performed using RevMan 5.3 for pooled proportions of findings in first infection and reinfection with a 95% confidence interval (CI).

RESULTS

Eighty-one studies reporting 577 cases were included from 22 countries. The mean age of patients was 46.2 ± 18.9 years and 179 (31.0%) cases of comorbidities were reported. The average time duration between first infection and reinfection was 63.6 ± 48.9 days. During first infection and reinfection, fever was the most common symptom (41.4% and 36.4%, respectively) whilst anti-viral therapy was the most common treatment regimen administered (44.5% and 43.0%, respectively). Comparable odds of symptomatic presentation and management were reported for the two infections. However, a higher Intensive Care Unit (ICU) admission rate was observed in reinfection compared to first infection (10 vs 3). Ten deaths were reported with respiratory failure being the most common cause of death (7/10 deaths).

CONCLUSION

Our findings support immunization practices given increased ICU admissions and mortality in reinfections. Our cohort serves as a guide for clinicians and authorities in devising an optimal strategy for controlling the pandemic. (249 words).

Duration of Viral Nucleic Acid Shedding and Early Reinfection With Severe Respiratory Syndrome Coronavirus 2 in Healthcare Workers and First Responders

We estimated the distributions of duration of SARS-CoV-2 nucleic acid shedding and time to reinfection among 137 persons with at least two positive nucleic acid amplification test (NAAT) results from March to September 2020. We analyzed gaps of varying length between subsequent positive and negative NAAT results and estimated a mean duration of nucleic acid shedding of 30.1 (95% CI 26.3, 34.5) days. The mean time to reinfection was 89.1 (95% CI 75.3, 103.5) days. Together, these indicate that a 90-day period between positive NAAT results can reliably define reinfection in immunocompetent persons although reinfection can occur at shorter intervals.

Clinical features and independent predictors for recurrence of positive SARS-CoV-2 RNA: A propensity score-matched analysis

Patients with COVID‐19 may be recurrence positive for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) RNA after being cured and discharged from the hospital. The aim of this study was to explore independent influencing factors as markers for predicting positive SARS‐CoV‐2 RNA recurrence. The study included 601 COVID‐19 patients who were cured and discharged from the Public and Health Clinic Centre of Chengdu from January 2020 to March 2021, and the recurrence positive of patients within 6 weeks after SARS‐CoV‐2 RNA turned negative was followed up. We used propensity score matching to eliminate the influence of confounding factors, and multivariate Logistic regression analysis was used to determine the independent influencing factors for positive SARS‐CoV‐2 RNA recurrence. Multivariate Logistic regression showed that the elevated serum potassium (odds ratio [OR] = 6.537, 95% confidence interval [CI]: 1.864–22.931, p = 0.003), elevated blood chlorine (OR = 1.169, 95% CI: 1.032–1.324, p = 0.014) and elevated CD3⁺CD4⁺ count (OR = 1.003, 95% CI: 1.001–1.004, p < 0.001) were identified as independent risk factors for positive SARS‐CoV‐2 RNA recurrence (p < 0.05). The difference in virus shedding duration (OR = 1.049, 95% CI: 1.000–1.100, p = 0.05) was borderline statistically significant. For sensitivity analysis, we included virus shedding duration as a categorical variable in the model again and found that the OR value related to recurrence positively increased with delayed virus shedding duration, and the trend test showed a statistical difference (P trend = 0.03). Meanwhile, shortening of activated partial prothrombinase time (OR = 0.908, 95% CI: 0.824–1.000, p = 0.049) was identified as an independent protection factor for SARS‐CoV‐2 RNA recurrence positive. We have identified independent factors that affect the recurrence of SARS‐CoV‐2 RNA positive. It is recommended that doctors pay attention to these indicators when first admitted to the hospital.

SARS-CoV-2 in Urine May Predict a Severe Evolution of COVID-19

We hypothesized that the spread of SARS-CoV-2 in urine during a severe COVID-19 infection may be the expression of the worsening disease evolution. Therefore, the aim of this study was to verify if the COVID-19 disease severity is related to the viral presence in urine samples. We evaluated the clinical evolution in acute COVID-19 patients admitted in the sub-intensive care and intensive care units between 28 of December 2020 and 15th of February 2021 and being positive for SARS-CoV-2 RNA in the respiratory tract, including repeated endotracheal aspirates (ETA), sputum, nasopharyngeal swabs (NPS) and urine. We found that those subjects with SARS-COV-2 in the urine at admittance (8 out of 60 eligible patients) had a more severe disease than those with negative SARS-CoV-2 in urine. Further, they showed an increase in fibrinogen and (C-reactive Protein) CRP serum levels, requiring mechanic ventilation. Of those with positive SARS-CoV-2 in the urine, 50% died. According to our preliminary results, it seems that the presence of SARS-CoV-2 in the urine characterizes patients with a more severe disease and is also related to a higher death rate.

Elucidating reasons of COVID-19 re-infection and its management strategies

BACKGROUND AND AIMS

Reinfection is gradually being recognised after symptomatic or asymptomatic COVID-19 infection. We try to elucidate various explanations behind COVID-19 reinfection and suggest possible strategies to counteract this threat.

METHODS

We carried out a comprehensive review of the literature using suitable keywords such as 'COVID-19', 'Pandemics', 'Reinfection', 'Vaccines' and 'India' on the search engines of PubMed, SCOPUS, Google Scholar and Research Gate in March 2021 and first half of April 2021 during the current COVID-19 pandemic. Epidemiology, risk factors and trends of reinfection were assessed.

RESULTS

A multitude of factors have been associated with rising incidence of COVID-19 reinfection in India and across the world. Emergence of 'Variants of Concern (VOC)', pandemic fatigue and disregard of infection prevention strategies appear to be the most obvious reasons.

CONCLUSIONS

COVID-19 reinfection is an emerging concern amongst the worldwide population with newer mutant strains demonstrating increasing transmissibility and responsible for continuing waves of the pandemic. COVID Appropriate Behaviour (CAB), improvised vaccines and enhanced vaccination drives are necessary to mitigate global threat.

Immunoglobulin Response and Prognostic Factors in Repeated SARS-CoV-2 Positive Patients: A Systematic Review and Meta-Analysis

With repeated positivity being an undiscovered and major concern, we aimed to evaluate which prognostic factors may impact repeated SARS-CoV-2 positivity (RSP) and their association with immunoglobulin detectability among recovered patients. A systematic literature search was performed on 5 April 2021. Cohort studies with risk factors for repeated RSP or information about the immunoglobulin response (immunoglobulin M (IgM) and/or immunoglobulin G (IgG)) were included in this analysis. The main examined risk factors were severity of the initial infection, body mass index (BMI), length of hospitalization (LOH), age, and gender, for which we pooled mean differences and odds ratios (ORs). Thirty-four cohort studies (N = 9269) were included in our analysis. We found that increased RSP rate might be associated with IgG positivity; IgG presence was higher in RSP patients (OR: 1.72, CI: 0.87–3.41, p = 0.117). Among the examined risk factors, only mild initial disease course showed a significant association with RSP (OR: 0.3, CI: 0.14–0.67, p = 0.003). Age, male gender, BMI, LOH, and severity of the first episode do not seem to be linked with repeated positivity. However, further prospective follow-up studies focusing on this topic are required.