Mortality Benefit of Convalescent Plasma in COVID-19: A Systematic Review and Meta-Analysis

The association between early corticosteroid use and the risk of secondary infections in hospitalized patients with COVID-19: a double-edged sword. Results from the international SCCM discovery viral infection and respiratory illness universal study (VIRUS) COVID-19 registry

Background

Corticosteroids improve survival in hospitalized COVID-19 patients needing supplemental oxygen. However, concern exists about increased risk of secondary infections. This study investigated the impact of early corticosteroids use on these infections.

Methods

Data from the Society of Critical Care Medicine Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS): COVID-19 registry were analyzed for adult patients, stratified by early corticosteroid use (within 48 h of admission). The primary outcome was documented secondary infections, including bacteremia, bacterial pneumonia, empyema, meningitis/encephalitis, septic shock, and ventilator-associated pneumonia. Univariate and multivariable logistic regression models were used to assess the association between early corticosteroids and these outcomes.

Results

Among 17,092 eligible patients, with 13.5% developed at least one secondary bacterial infection during hospitalization. Patients receiving early corticosteroids were older (median 63 years) compared to those who did not (median 60 years), with a similar gender distribution (42.5% vs. 44.2% female). Unadjusted analysis revealed a higher risk for any secondary infection (OR 1.93, 95% CI 1.76-2.12). This association persisted for specific infections including bacteremia (OR 2.0, 95% CI 1.58-2.54), bacterial pneumonia (OR 1.5, 95% CI 1.27-1.77), and septic shock (OR 1.67, 95% CI 1.44-1.93). However, the effect on meningitis/encephalitis (OR 0.62, 95% CI 0.24-1.57) and ventilator-associated pneumonia (VAP; OR 1.08, 95% CI 0.75-1.57) was non-significant. Adjusted analysis maintained significance for any secondary infection (OR 1.15, 95% CI 1.02-1.29), bacteremia (OR 1.43, 95% CI 1.09-1.88), and infections with unknown sources (OR 1.63, 95% CI 1.31-2.02). Notably, the association weakened and became non-significant for bacterial pneumonia (OR 0.98, 95% CI 0.81-1.20) and septic shock (OR 0.94, 95% CI 0.79-1.11), while it became significant for meningitis/encephalitis (OR 0.26, 95% CI 0.08-0.82). VAP remained non-significant (OR 0.87, 95% CI 0.56-1.34).

Conclusion

Early use of corticosteroids increased overall secondary infection risk in hospitalized COVID-19 patients, but the impact varied. Risk of bacteremia was notably increased, while the association with bacterial pneumonia and septic shock weakened after adjustment becoming non-significant and surprisingly reduced meningitis/encephalitis risk was noted suggesting the complexity of corticosteroid effects. Further research is needed to understand how corticosteroids influence specific secondary infections, and thereby optimize the treatment strategies.

Anticoagulant use before COVID-19 diagnosis prevent COVID-19 associated acute venous thromboembolism or not: A systematic review and meta-analysis

BACKGROUND

Coagulopathy and thromboembolic events are associated with poor outcomes in coronavirus disease 2019 (COVID-19) patients. There is conflicting evidence on the effects of chronic anticoagulation on mortality and severity of COVID-19 disease.

AIM

To summarize the body of evidence on the effects of pre-hospital anticoagulation on outcomes in COVID-19 patients.

METHODS

A Literature search was performed on LitCovid PubMed, WHO, and Scopus databases from inception (December 2019) till June 2023 for original studies reporting an association between prior use of anticoagulants and patient outcomes in adults with COVID-19. The primary outcome was the risk of thromboembolic events in COVID-19 patients taking anticoagulants. Secondary outcomes included COVID-19 disease severity, in terms of intensive care unit admission or invasive mechanical ventilation/intubation requirement in patients hospitalized with COVID-19 infection, and mortality. The random effects models were used to calculate crude and adjusted odds ratios (aORs) with 95% confidence intervals (95%CIs).

RESULTS

Forty-six observational studies met our inclusion criteria. The unadjusted analysis found no association between prior anticoagulation and thromboembolic event risk [n = 43851, 9 studies, odds ratio (OR)= 0.67 (0.22, 2.07); P = 0.49; I 2 = 95%]. The association between prior anticoagulation and disease severity was non-significant [n = 186782; 22 studies, OR = 1.08 (0.78, 1.49); P = 0.64; I 2 = 89%]. However, pre-hospital anticoagulation significantly increased all-cause mortality risk [n = 207292; 35 studies, OR = 1.72 (1.37, 2.17); P < 0.00001; I 2 = 93%]. Pooling adjusted estimates revealed a statistically non-significant association between pre-hospital anticoagulation and thromboembolic event risk [aOR = 0.87 (0.42, 1.80); P = 0.71], mortality [aOR = 0.94 (0.84, 1.05); P = 0.31], and disease severity [aOR = 0.96 (0.72, 1.26); P = 0.76].

CONCLUSION

Prehospital anticoagulation was not significantly associated with reduced risk of thromboembolic events, improved survival, and lower disease severity in COVID-19 patients.

Association of hypothyroidism with outcomes in hospitalized adults with COVID-19: Results from the International SCCM Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS): COVID-19 Registry

INTRODUCTION

Coronavirus disease 2019 (COVID-19) is associated with high rates of morbidity and mortality. Primary hypothyroidism is a common comorbid condition, but little is known about its association with COVID-19 severity and outcomes. This study aims to identify the frequency of hypothyroidism in hospitalized patients with COVID-19 as well as describe the differences in outcomes between patients with and without pre-existing hypothyroidism using an observational, multinational registry.

METHODS

In an observational cohort study we enrolled patients 18 years or older, with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 infection between March 2020 and February 2021. The primary outcomes were (1) the disease severity defined as per the World Health Organization Scale for Clinical Improvement, which is an ordinal outcome corresponding with the highest severity level recorded during a patient's index COVID-19 hospitalization, (2) in-hospital mortality and (3) hospital-free days. Secondary outcomes were the rate of intensive care unit (ICU) admission and ICU mortality.

RESULTS

Among the 20,366 adult patients included in the study, pre-existing hypothyroidism was identified in 1616 (7.9%). The median age for the Hypothyroidism group was 70 (interquartile range: 59-80) years, and 65% were female and 67% were White. The most common comorbidities were hypertension (68%), diabetes (42%), dyslipidemia (37%) and obesity (28%). After adjusting for age, body mass index, sex, admission date in the quarter year since March 2020, race, smoking history and other comorbid conditions (coronary artery disease, hypertension, diabetes and dyslipidemia), pre-existing hypothyroidism was not associated with higher odds of severe disease using the World Health Organization disease severity index (odds ratio [OR]: 1.02; 95% confidence interval [CI]: 0.92, 1.13; p = .69), in-hospital mortality (OR: 1.03; 95% CI: 0.92, 1.15; p = .58) or differences in hospital-free days (estimated difference 0.01 days; 95% CI: -0.45, 0.47; p = .97). Pre-existing hypothyroidism was not associated with ICU admission or ICU mortality in unadjusted as well as in adjusted analysis.

CONCLUSIONS

In an international registry, hypothyroidism was identified in around 1 of every 12 adult hospitalized patients with COVID-19. Pre-existing hypothyroidism in hospitalized patients with COVID-19 was not associated with higher disease severity or increased risk of mortality or ICU admissions. However, more research on the possible effects of COVID-19 on the thyroid gland and its function is needed in the future.

A systematic review and meta-analysis of new-onset atrial fibrillation in the context of COVID-19 infection

New-onset atrial fibrillation (NOAF) in COVID-19 raises significant clinical and public health issues. This systematic review and meta-analysis aims to compile and analyze the current literature on NOAF in COVID-19 and give a more comprehensive understanding of the prevalence and outcomes of NOAF in COVID-19. A comprehensive literature search was carried out using several databases. The random effect model using inverse variance method and DerSimonian and Laird estimator of Tua2 was used to calculate the pooled prevalence and associated 95% confidence interval (CI). Results for outcome analysis were presented as odds ratios (ORs) with 95% CI and pooled using the Mantel-Haenszel random-effects model. The pooled prevalence of NOAF in COVID-19 was 7.8% (95% CI: 6.54%-9.32%),a pooled estimate from 30 articles (81 929 COVID-19 patients). Furthermore, our analysis reported that COVID-19 patients with NOAF had a higher risk of developing severe disease compared with COVID-19 patients without a history of atrial fibrillation (OR = 4.78, 95% CI: 3.75-6.09) and COVID-19 patients with a history of pre-existing atrial fibrillation (OR = 2.75, 95% CI: 2.10-3.59). Similarly, our analysis also indicated that COVID-19 patients with NOAF had a higher risk of all-cause mortality compared with, COVID-19 patients without a history of atrial fibrillation (OR = 3.83, 95% CI: 2.99-4.92) and COVID-19 patients with a history of pre-existing atrial fibrillation (OR = 2.32, 95% CI: 1.35-3.96). The meta-analysis did not reveal any significant publication bias. The results indicate a strong correlation between NOAF and a higher risk of severe illness and mortality. These results emphasize the importance of careful surveillance, early detection, and customized NOAF management strategies to improve clinical outcomes for COVID-19 patients.

Convalescent plasma and all-cause mortality of COVID-19 patients: systematic review and meta-analysis

Insight into the clinical potential of convalescent plasma in patients with coronavirus disease (COVID-19) is important given the severe clinical courses in unvaccinated and seronegative individuals. The aim of the study was to investigate whether there is a survival benefit of convalescent plasma therapy in COVID-19 patients. The authors independently assessed randomized controlled trials (RCTs) identified by the search strategy for inclusion, extracted data, and assessed risk of bias. The binary primary outcome was all-cause mortality. Risk ratio (RR) of the convalescent plasma treatment (vs. best standard care) and its associated standard error (effect size) were calculated. A random-effects model was employed to statistically pool the effect sizes of the selected studies. We included 19 RCTs with 17,021 patients. The random-effects model resulted in an estimated pooled RR of 0.94 (95% CI 0.81-1.08, p = 0.33), showing no statistical evidence of the benefit of convalescent plasma therapy on all-cause mortality. Convalescent plasma therapy was not found to be effective in reducing all-cause mortality in COVID-19 patients. Further studies are needed to determine in which patients convalescent plasma therapy may lead to a reduction in mortality.

Too Early to Abandon Convalescent Plasma for Supportive Treatment of COVID-19

The authors of a systematic review and meta-analysis conclude that the benefit of convalescent plasma (CP) in the treatment of COVID-19 is limited. Among other systematic reviews, only one found an indication of benefit of CP. However, a meta-analysis needs a focused and meaningful clinical question and should include studies which are designed to test a reasonable hypothesis. Clinical trials to support the licensing of medicines should aim to define as exactly as possible the investigational drug and target disease. In the case of COVID-19, trial details (e.g., duration, stage and severity of disease, and antibody content and dose of CP) are quite heterogeneous. The so far available evidence suggests that the hypothesis should be sharpened as to treat COVID -19 patients at risk for developing severe disease as early enough with a sufficiently high dose of specific antibodies. It has been demonstrated that such an approach is feasible, and the lack of an independent reproduction by further trials with a really comparable design can probably not be compensated by compiling all available, heterogenous trials, even with the best methodology of a systematic review and meta-analysis. Though the COVID-19 pandemic appears to be fading, we should not neglect the search for effective prevention and treatments, given the still high death toll of COVID-19. Monoclonal antibodies were found effective in the early phase of the pandemic; however, due to new variants of SARS-COV2 undermining their efficacy they are no longer recommended by the current NIH guidelines. CP can provide a spectrum of polyclonal antibodies in close timely and regional connection to the particular prevalent virus variant. It would be extremely valuable to obtain a solid scientific foundation for the principle of target specific and temporarily adapted passive immunization, which could be a fast and flexible instrument also in future outbreaks of novel pathogens.

COVID 19 convalescent plasma: Is there still a place for CCP?

BACKGROUND

Convalescent plasma has been used for a long time for the treatment of various infectious diseases. The principle is to collect antibody-containing plasma from recovered patients and to transfuse the plasma to infectious patients thereby modifying their immune system. This approach was also used in the SARS-CoV-2 pandemic when no specific drugs were available for the treatment of the disease.

DESIGN AND METHODS

This short narrative review reports on relevant studies of collection and transfusion of Covid-19 convalescent plasma (CCP) from 2020 until August 2022. Clinical patients' outcome parameters such as need for ventilation, length of hospital stay and mortality were analysed.

RESULTS

Heterogenous patient groups were studied resulting in difficult comparability of the studies. High titer of transfused neutralizing antibodies, early onset of CCP treatment and moderate disease activity were identified as key parameters for effective treatment. Special subgroups of patients were identified to benefit from CCP treatment. No relevant side effects were observed during and after collection and transfusion of CCP.

CONCLUSIONS

Transfusion of CCP plasma is an option for the treatment of special subgroups of patients suffering from SARS-CoV-2 infection. CCP can be easily used in low-to-middle income countries where no specific drugs are available for treatment of the disease. Further clinical trials are necessary to define the role of CCP in the treatment of SARS-CoV-2 disease.

Effect of convalescent plasma transfusion on outcomes of coronavirus disease 2019: a meta-analysis with trial sequential analysis

The aim of this review was to update evidence for benefit of convalescent plasma transfusion (CPT) in patients with coronavirus disease 2019 (COVID-19). Databases were searched for randomized controlled trials (RCT) comparing CPT plus standard treatment versus standard treatment only in adults with COVID-19. Primary outcome measures were mortality and need for invasive mechanical ventilation (IMV). Twenty-Six RCT involving 19,816 patients were included in meta-analysis for mortality. Quantitative synthesis showed no statistically significant benefit of adding CPT to standard treatment (RR = 0.97, 95% CI = 0.92 to 1.02) with unimportant heterogeneity (Q(25) = 26.48, p = .38, I² = 0.00%). Trim-and-fill-adjusted effect size was unimportantly changed and level of evidence was graded as high. Trial sequential analysis (TSA) indicated information size was adequate and CPT was futile. Seventeen trials involving 16,083 patients were included in meta-analysis for need of IMV. There was no statistically significant effect of CPT (RR = 1.02, 95% CI = 0.95 to 1.10) with unimportant heterogeneity (Q(16) = 9.43, p = .89, I² = 3.30%). Trim-and-fill-adjusted effect size was trivially changed and level of evidence was graded as high. TSA showed information size was adequate and indicated futility of CPT. It is concluded with high level of certainty that CPT added to standard treatment of COVID-19 is not associated with reduced mortality or need of IMV compared with standard treatment alone. In view of these findings, further trials on efficacy of CPT in COVID-19 patients are probably not needed.

Prevalence and clinical outcomes of COVID-19 in patients with pre-existing celiac disease: A systematic review and meta-analysis

There is a scarcity of scientific evidence addressing the outcomes of COVID-19 in celiac disease (CD) patients. This systematic review and meta-analysis aimed to evaluate the correlation between pre-existing CD and COVID-19. A rigorous literature search was conducted using multiple databases. All eligible observational studies were included from around the globe. The random effect model calculated the pooled prevalence and associated 95% confidence intervals (CI). Mantel-Haenszel odds ratios were produced to report the overall effect size using random effect models for severity and mortality outcomes. Funnel plots, Egger regression tests, and Begg-Mazumdar's rank correlation test were used to appraise publication bias. Data from 11 articles consisting of 44,378 CD patients were obtained. Overall pooled random-effects estimate of SARS-CoV-2 infection in CD patients was 4.25% (95% CI, I²  = 98%). Our findings also indicated that pre-existing CD was not associated with an increased risk of hospitalisation with COVID-19 illness (OR = 1.04, 95% CI 0.87-1.24, I²  = 0%) and mortality due to illness (OR = 0.92, 95% CI 0.56-1.5, I²  = 45%) compared with patients without pre-existing CD. No significant publication bias was evident in the meta-analysis. The preliminary data from our analysis suggest that SARS-CoV-2 infection in patients with pre-existing CD is not associated with an increased risk of hospitalisation or mortality. Additional studies are required to overcome the restrictions of the limited data available at present.

The evidence base for emergency use authorizations for COVID-19 treatments: A rapid review

Background and Aims

During the COVID-19 pandemic, US Food and Drug Administration (FDA) permitted emergency use authorizations (EUAs) for vaccines/treatments with promising data. Eight treatments were issued EUAs by May 31, 2021; one of these was approved (Remdesivir for certain populations) and two were revoked (chloroquine phosphate/hydroxychloroquine and bamlanivimab) by September 30, 2021. The aim of this study is to find out what evidence the EUAs were based on and how many studies were published while they remained active (up to September 30, 2021).

Methods

A review of published clinical studies for the 6 months before each EUA was issued, and the time after (until September 30, 2021, or until revoked). PubMed and the identified systematic reviews were the sources for identifying published literature.

Results

The number of clinical studies published pre-EUA varied from a single case study (for chloroquine phosphate/hydroxychloroquine) to numerous studies of multiple types (for convalescent plasma). Four treatments had a single randomized controlled trial (RCT) as evidence (bamlanivimab monotherapy, REGN-COV, bamlanivimab + etesevimab, sotrovimab) and two also had other study types (remdesivir and baricitinib). The number of clinical studies published post-EUA (for those active on September 30, 2021) was widely varied. Eighteen RCTs were published for Convalescent plasma, while Remdesivir had eight. Baricitinib, REGN-COV, and bamlanivimab + etesevimab all had one, but none were published for sotrovimab.

Conclusion

The number of trials for treatments with EUAs was limited in all cases before the EUA was issued, and in most cases for those with EUAs ongoing at the end of September 2021. The presence of EUAs may discourage participation in relevant clinical trials, which delays the widespread implementation of evidenced-based therapies. Large, robust RCTs should be completed, such as the RECOVERY trial in the United Kingdom, to quickly find the answers desperately required during a pandemic.

Comparison of allocation strategies of convalescent plasma to reduce excess infections and mortality from SARS-CoV-2 in a US-like population

BACKGROUND

While the use of convalescent plasma (CP) in the ongoing COVID-19 pandemic has been inconsistent, CP has the potential to reduce excess morbidity and mortality in future pandemics. Given constraints on CP supply, decisions surrounding the allocation of CP must be made.

STUDY DESIGN AND METHODS

Using a discrete-time stochastic compartmental model, we simulated implementation of four potential allocation strategies: administering CP to individuals in early hospitalization with COVID-19; administering CP to individuals in outpatient settings; administering CP to hospitalized individuals and administering any remaining CP to outpatient individuals and administering CP in both settings while prioritizing outpatient individuals. We examined the final size of SARS-CoV-2 infections, peak and cumulative hospitalizations, and cumulative deaths under each of the allocation scenarios over a 180-day period. We compared the cost per weighted health benefit under each strategy.

RESULTS

Prioritizing administration to patients in early hospitalization, with remaining plasma administered in outpatient settings, resulted in the highest reduction in mortality, averting on average 15% more COVID-19 deaths than administering to hospitalized individuals alone (95% CI [11%-18%]). Prioritizing administration to outpatients, with remaining plasma administered to hospitalized individuals, had the highest percentage of hospitalizations averted (22% [21%-23%] higher than administering to hospitalized individuals alone).

DISCUSSION

Convalescent plasma allocation strategy should be determined by the relative priority of averting deaths, infections, or hospitalizations. Under conditions considered, mixed allocation strategies (allocating CP to both outpatient and hospitalized individuals) resulted in a larger percentage of infections and deaths averted than administering CP in a single setting.

SARS-CoV-2: An Updated Review Highlighting Its Evolution and Treatments

Since the SARS-CoV-2 outbreak, pharmaceutical companies and researchers worldwide have worked hard to develop vaccines and drugs to end the SARS-CoV-2 pandemic. The potential pathogen responsible for Coronavirus Disease 2019 (COVID-19), SARS-CoV-2, belongs to a novel lineage of beta coronaviruses in the subgenus arbovirus. Antiviral drugs, convalescent plasma, monoclonal antibodies, and vaccines are effective treatments for SARS-CoV-2 and are beneficial in preventing infection. Numerous studies have already been conducted using the genome sequence of SARS-CoV-2 in comparison with that of other SARS-like viruses, and numerous treatments/prevention measures are currently undergoing or have already undergone clinical trials. We summarize these studies in depth in the hopes of highlighting some key details that will help us to better understand the viral origin, epidemiology, and treatments of the virus.

Rate of COVID-19 infection and 30 day mortality between blue and green (dedicated COVID-19 safe) pathways: Results from phase 1 and 2 of the UK foot and ankle COVID-19 national (UK-FAlCoN) audit

OBJECTIVES

The primary aim was to determine the differences in COVID-19 infection rate and 30-day mortality in patients undergoing foot and ankle surgery between different treatment pathways over the two phases of the UK-FALCON audit, spanning the first and second UK national lockdowns.

SETTING

This was an ambispective (retrospective Phase 1 and prospective Phase 2) national audit of foot and ankle procedures in the UK in 2020 completed between 13th January 2020 and 30th November 2020.

PARTICIPANTS

All adult patients undergoing foot and ankle surgery in an operating theatre during the study period were included from 46 participating centres in England, Scotland, Wales and Northern Ireland. Patients were categorised as either a green pathway (designated COVID-19 free) or blue pathway (no protocols to prevent COVID-19 infection).

RESULTS

10,846 patients were included, 6644 from phase 1 and 4202 from phase 2. Over the 2 phases the infection rate on a blue pathway was 1.07% (69/6470) and 0.21% on a green pathway (9/4280). In phase 1, there was no significant difference in the COVID-19 perioperative infection rate between the blue and green pathways in any element of the first phase (pre-lockdown (p = .109), lockdown (p = .923) or post-lockdown (p = .577)). However, in phase 2 there was a significant reduction in perioperative infection rate when using the green pathway in both the pre-lockdown (p < .001) and lockdown periods (Odd's Ratio 0.077, p < .001). There was no significant difference in COVID-19 related mortality between pathways.

CONCLUSIONS

There was a five-fold reduction in the perioperative COVID-19 infection rate when using designated COVID-19 green pathways over the whole study period; however the success of the pathways only became significant in phase 2 of the study, where there was a 13-fold reduction in infection rate. The study shows a developing success to using green pathways in reducing the risk to patients undergoing foot and ankle surgery.

COVID-19-Induced Seizures: A Meta-Analysis of Case Series and Retrospective Cohorts

The adverse events and complications of coronavirus disease 2019 (COVID-19) continue to challenge the medical profession despite the worldwide vaccination against the severe acute respiratory coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. Other than typical respiratory manifestations, COVID-19 also presents a wide range of neurological manifestations. This article underlines the pooled incidence of COVID-19-induced seizures in patients with epilepsy and without epilepsy. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocols, we conducted a bibliographical search, and an initial search revealed 1,375 articles. In total, 21 articles were included in the final analysis by following the inclusion criteria. A total of 11,526 patients from 21 published articles that met the predetermined search criteria were included. The median age of the patients was 61.9 years, of whom 51.5% were males. A total of 255 patients presented with seizures as the first manifestation of COVID-19 with a prevalence of 2.2% (95% confidence interval = 0.05-0.24, p < 0.01) (I² = 97%), of which 71 patients had previously been diagnosed with epilepsy. Among patients with epilepsy, 49 patients had seizures as an initial presentation of SARA-CoV-2 with an incidence of 72% (0.54-0.85, p = 0.1) (I² = 34). Although the incidence of COVID-19-induced seizures is not high compared to other neurological manifestations, seizure incidence in epileptic patients with COVID-19 is remarkably high. New-onset seizures in any patient should be considered a presentation of COVID-19 in the absence of other causative factors.

Characterization of Pathogen Inactivated COVID ‐19 Convalescent Plasma and Responses in Transfused Patients

Background

Efficacy of donated COVID‐19 convalescent plasma (dCCP) is uncertain and may depend on antibody titers, neutralizing capacity, timing of administration, and patient characteristics.

Study Design and Methods

In a single‐center hypothesis‐generating prospective case–control study with 1:2 matched dCCP recipients to controls according to disease severity at day 1, hospitalized adults with COVID‐19 pneumonia received 2 × 200 ml pathogen‐reduced treated dCCP from 2 different donors. We evaluated severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) antibodies in COVID‐19 convalescent plasma donors and recipients using multiple antibody assays including a Coronavirus antigen microarray (COVAM), and binding and neutralizing antibody assays. Outcomes were dCCP characteristics, antibody responses, 28‐day mortality, and dCCP ‐related adverse events in recipients.

Results

Eleven of 13 dCCPs (85%) contained neutralizing antibodies (nAb). PRT did not affect dCCP antibody activity. Fifteen CCP recipients and 30 controls (median age 64 and 65 years, respectively) were enrolled. dCCP recipients received 2 dCCPs from 2 different donors after a median of one hospital day and 11 days after symptom onset. One dCCP recipient (6.7%) and 6 controls (20%) died (p = 0.233). We observed no dCCP‐related adverse events. Transfusion of unselected dCCP led to heterogeneous SARS CoV‐2 antibody responses. COVAM clustered dCCPs in 4 distinct groups and showed endogenous immune responses to SARS‐CoV‐2 antigens over 14–21 days post dCCP in all except 4 immunosuppressed recipients.

Discussion

PRT did not impact dCCP anti‐virus neutralizing activity. Transfusion of unselected dCCP did not impact survival and had no adverse effects. Variable dCCP antibodies and post‐transfusion antibody responses indicate the need for controlled trials using well‐characterized dCCP with informative assays.

Association of Obesity With COVID-19 Severity and Mortality: An Updated Systemic Review, Meta-Analysis, and Meta-Regression

Background

Obesity affects the course of critical illnesses. We aimed to estimate the association of obesity with the severity and mortality in coronavirus disease 2019 (COVID-19) patients.

Data Sources

A systematic search was conducted from the inception of the COVID-19 pandemic through to 13 October 2021, on databases including Medline (PubMed), Embase, Science Web, and Cochrane Central Controlled Trials Registry. Preprint servers such as BioRxiv, MedRxiv, ChemRxiv, and SSRN were also scanned.

Study Selection and Data Extraction

Full-length articles focusing on the association of obesity and outcome in COVID-19 patients were included. Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were used for study selection and data extraction. Our Population of interest were COVID-19 positive patients, obesity is our Intervention/Exposure point, Comparators are Non-obese vs obese patients The chief outcome of the study was the severity of the confirmed COVID-19 positive hospitalized patients in terms of admission to the intensive care unit (ICU) or the requirement of invasive mechanical ventilation/intubation with obesity. All-cause mortality in COVID-19 positive hospitalized patients with obesity was the secondary outcome of the study.

Results

In total, 3,140,413 patients from 167 studies were included in the study. Obesity was associated with an increased risk of severe disease (RR=1.52, 95% CI 1.41-1.63, p<0.001, I2 = 97%). Similarly, high mortality was observed in obese patients (RR=1.09, 95% CI 1.02-1.16, p=0.006, I2 = 97%). In multivariate meta-regression on severity, the covariate of the female gender, pulmonary disease, diabetes, older age, cardiovascular diseases, and hypertension was found to be significant and explained R2 = 40% of the between-study heterogeneity for severity. The aforementioned covariates were found to be significant for mortality as well, and these covariates collectively explained R2 = 50% of the between-study variability for mortality.

Conclusions

Our findings suggest that obesity is significantly associated with increased severity and higher mortality among COVID-19 patients. Therefore, the inclusion of obesity or its surrogate body mass index in prognostic scores and improvement of guidelines for patient care management is recommended.

Comparison of Two Waves of COVID-19 in Critically Ill Patients: A Retrospective Observational Study

Background

The SARS-CoV-2 virus caused the global COVID-19 pandemic, with waxing and waning course. This study was conducted to compare outcomes in the first two waves, in mechanically ventilated patients.

Methods

This retrospective observational study included all mechanically ventilated COVID-19 patients above 18 years of age, between March 2020 and January 2021. Patients were grouped into first wave from March 2020 to July 2020, and second wave from August 2020 to January 2021. Outcome measures were mortality, the development of acute kidney injury (AKI), and need for renal replacement therapy (RRT). Univariate and multivariate cox regression analysis were used to delineate risk factors for the outcome measures.

Results

A total of 426 patients, 285 in the first wave and 185 in the second wave, were included. The incidence of AKI was significantly lower in the second wave (72% vs. 63%; p=0.04). There was no significant difference in mortality (70% vs. 63%; p=0.16) and need for RRT (36% vs. 30%; p=0.1). Risk factors for mortality were increasing age and AKI in both waves, and chronic kidney disease (CKD) (adj. HR 1.7; 95% CI 1.02-2.68; p=0.04) in the second wave. Risk factors for AKI were CKD in both the waves, while it was diabetes (adj. HR 1.4; 95% CI 1.02-1.95; p=0.04) and increasing age in the first wave. Remdesivir (adj. HR 0.5; 95% CI 0.3-0.7; p < 0.01) decreased the risk of AKI, and convalescent plasma (adj. HR 0.5; 95% CI 0.3-0.9; p=0.02) decreased the risk of mortality in the first wave, however, such benefit was not observed in the second wave.

Conclusions

Our study shows a decrease in the incidence of AKI in critically ill patients, however, the reason for this decrease is still unknown. Studies comparing the waves of the pandemic would not only help in understanding disease evolution but also to develop tailored management strategies.

SARS-CoV-2 antibody changes in patients receiving COVID-19 convalescent plasma from normal and vaccinated donors

Vaccination has been shown to stimulate remarkably high antibody levels in donors who have recovered from COVID-19. Our objective was to measure patient antibody levels before and after transfusion with COVID-19 Convalescent Plasma (CCP) and compare the antibody levels following transfusion of CCP from vaccinated and nonvaccinated donors. Plasma samples before and after transfusion were obtained from 25 recipients of CCP and COVID-19 antibody levels measured. Factors that effect changes in antibody levels were examined. In the 21 patients who received CCP from nonvaccinated donors, modest increases in antibody levels were observed. Patients who received two units were more likely to seroconvert than those receiving just one unit. The strongest predictor of changes in patient antibody level was the CCP dose, calculated by the unit volume multiplied by the donor antibody level. Using patient plasma volume and donor antibody level, the post-transfusion antibody level could be predicted with reasonable accuracy(R²> 0.90). In contrast, the 4 patients who received CCP from vaccinated donors all had dramatic increases in antibody levels following transfusion of a single unit. In this subset of recipients, antibody levels observed after transfusion of CCP were comparable to those seen in donors who had fully recovered from COVID-19. If available, CCP from vaccinated donors with very high antibody levels should be used. One unit of CCP from vaccinated donors increases patient antibody levels much more than 1 or 2 units of CCP from unvaccinated donors.

Association of latitude and altitude with adverse outcomes in patients with COVID-19: The VIRUS registry

BACKGROUND

The coronavirus disease 2019 (COVID-19) course may be affected by environmental factors. Ecological studies previously suggested a link between climatological factors and COVID-19 fatality rates. However, individual-level impact of these factors has not been thoroughly evaluated yet.

AIM

To study the association of climatological factors related to patient location with unfavorable outcomes in patients.

METHODS

In this observational analysis of the Society of Critical Care Medicine Discovery Viral Infection and Respiratory Illness Universal Study: COVID-19 Registry cohort, the latitudes and altitudes of hospitals were examined as a covariate for mortality within 28 d of admission and the length of hospital stay. Adjusting for baseline parameters and admission date, multivariable regression modeling was utilized. Generalized estimating equations were used to fit the models.

RESULTS

Twenty-two thousand one hundred eight patients from over 20 countries were evaluated. The median age was 62 (interquartile range: 49-74) years, and 54% of the included patients were males. The median age increased with increasing latitude as well as the frequency of comorbidities. Contrarily, the percentage of comorbidities was lower in elevated altitudes. Mortality within 28 d of hospital admission was found to be 25%. The median hospital-free days among all included patients was 20 d. Despite the significant linear relationship between mortality and hospital-free days (adjusted odds ratio (aOR) = 1.39 (1.04, 1.86), P = 0.025 for mortality within 28 d of admission; aOR = -1.47 (-2.60, -0.33), P = 0.011 for hospital-free days), suggesting that adverse patient outcomes were more common in locations further away from the Equator; the results were no longer significant when adjusted for baseline differences (aOR = 1.32 (1.00, 1.74), P = 0.051 for 28-day mortality; aOR = -1.07 (-2.13, -0.01), P = 0.050 for hospital-free days). When we looked at the altitude's effect, we discovered that it demonstrated a non-linear association with mortality within 28 d of hospital admission (aOR = 0.96 (0.62, 1.47), 1.04 (0.92, 1.19), 0.49 (0.22, 0.90), and 0.51 (0.27, 0.98), for the altitude points of 75 MASL, 125 MASL, 400 MASL, and 600 MASL, in comparison to the reference altitude of 148 m.a.s.l, respectively. P = 0.001). We detected an association between latitude and 28-day mortality as well as hospital-free days in this worldwide study. When the baseline features were taken into account, however, this did not stay significant.

CONCLUSION

Our findings suggest that differences observed in previous epidemiological studies may be due to ecological fallacy rather than implying a causal relationship at the patient level.

Cross-Neutralizing Breadth and Longevity Against SARS-CoV-2 Variants After Infections

Background

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the virus responsible for the Coronavirus Disease 2019 (COVID-19) pandemic. The emergence of variants of concern (VOCs) has become one of the most pressing issues in public health. To control VOCs, it is important to know which COVID-19 convalescent sera have cross-neutralizing activity against VOCs and how long the sera maintain this protective activity.

Methods

Sera of patients infected with SARS-CoV-2 from March 2020 to January 2021 and admitted to Hyogo Prefectural Kakogawa Medical Center were selected. Blood was drawn from patients at 1-3, 3-6, and 6-8 months post onset. Then, a virus neutralization assay against SARS-CoV-2 variants (D614G mutation as conventional strain; B.1.1.7, P.1, and B.1.351 as VOCs) was performed using authentic viruses.

Results

We assessed 97 sera from 42 patients. Sera from 28 patients showed neutralizing activity that was sustained for 3-8 months post onset. The neutralizing antibody titer against D614G significantly decreased in sera of 6-8 months post onset compared to those of 1-3 months post onset. However, the neutralizing antibody titers against the three VOCs were not significantly different among 1-3, 3-6, and 6-8 months post onset.

Discussion

Our results indicate that neutralizing antibodies that recognize the common epitope for several variants may be maintained for a long time, while neutralizing antibodies having specific epitopes for a variant, produced in large quantities immediately after infection, may decrease quite rapidly.

The Role of Disease Severity and Demographics in the Clinical Course of COVID-19 Patients Treated With Convalescent Plasma

Treatment of patients with COVID-19 using convalescent plasma from recently recovered patients has been shown to be safe, but the time course of change in clinical status following plasma transfusion in relation to baseline disease severity has not yet been described. We analyzed short, descriptive daily reports of patient status in 7,180 hospitalized recipients of COVID-19 convalescent plasma in the Mayo Clinic Expanded Access Program. We assessed, from the day following transfusion, whether the patient was categorized by his or her physician as better, worse or unchanged compared to the day before, and whether, on the reporting day, the patient received mechanical ventilation, was in the ICU, had died or had been discharged. Most patients improved following transfusion, but clinical improvement was most notable in mild to moderately ill patients. Patients classified as severely ill upon enrollment improved, but not as rapidly, while patients classified as critically ill/end-stage and patients on ventilators showed worsening of disease status even after treatment with convalescent plasma. Patients age 80 and over showed little or no clinical improvement following transfusion. Clinical status at the time of convalescent plasma treatment and age appear to be the primary factors in determining the therapeutic effectiveness of COVID-19 convalescent plasma among hospitalized patients.

Convalescent plasma therapy against the emerging SARS-CoV-2 variants: Delineation of the potentialities and risks

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in a catastrophic pandemic and severely impacted people's livelihoods worldwide. In addition, the emergence of SARS-CoV-2 variants has posed a severe threat to humankind. Due to the dearth of therapeutic options during the commencement of the pandemic, convalescent plasma therapy (CPT) played a significant part in the management of patients with severe form of COVID-19. Several recent studies have proposed various protective effects of CPT, such as antiviral, anti-inflammatory, anti-thrombotic, and immunomodulatory actions, curtailing the devastating consequences of the SARS-CoV-2 infection. On the contrary, several clinical studies have raised some serious concerns about the effectiveness and reliability of CPT in the management of patients with COVID-19. The protective effects of CPT in severely ill patients are yet to be proved. Moreover, the emergence of SARS-CoV-2 variants has raised concerns about the effectiveness of CPT against COVID-19. Therefore, to establish concrete evidence of the efficacy of CPT and adjudicate its inclusion in the management of COVID-19, an updated review of present literature is required, which could help in the development of an efficient therapeutic regimen to treat COVID-19 amid the emergence of new viral variants.

Prevalence and clinical outcomes of pleural effusion in COVID-19 patients: A systematic review and meta-analysis

Observational studies indicate that pleural effusion has an association with risk and the clinical prognosis of COVID-19 disease; however, the available literature on this area is inconsistent. The objective of this systematic review and meta-analysis is to evaluate the correlation between COVID-19 disease and pleural effusion. A rigorous literature search was conducted using multiple databases. All eligible observational studies were included from around the globe. The pooled prevalence and associated 95% confidence interval (CI) were calculated using the random effect model. Mantel-Haenszel odds ratios were produced to report overall effect size using random effect models for severity and mortality outcomes. Funnel plots, Egger regression tests, and Begg-Mazumdar's rank correlation test were used to appraise publication bias. Data from 23 studies including 6234 COVID-19 patients was obtained. The overall prevalence of pleural effusion in COVID-19 patients was 9.55% (95% CI, I2  = 92%). Our findings also indicated that the presence of pleural effusions associated with increased risk of severity of disease(OR = 5.08, 95% CI 3.14-8.22, I2  = 77.4%) and mortality due to illness(OR = 4.53, 95% CI 2.16-9.49, I2  = 66%) compared with patients without pleural effusion. Sensitivity analyses illustrated a similar effect size while decreasing the heterogeneity. No significant publication bias was evident in the meta-analysis. The presence of pleural effusion can assist as a prognostic factor to evaluate the risk of worse outcomes in COVID-19 patients hence, it is recommended that hospitalized COVID-19 patients with pleural effusion should be managed on an early basis.

Immunological effects of convalescent plasma therapy for coronavirus: a scoping review

BACKGROUND

Preliminary studies revealed the safety and effectiveness of convalescent plasma (CP) therapy for patients with coronavirus. In this study, we aimed to evaluate and summarize the available evidence on CP therapy, identify the research gap regarding the immunological response to CP therapy and pave the road for future studies.

METHODS

This study was conducted according to the Hilary Arksey and Lisa O'Malley framework. To find out the relevant studies, we searched PubMed, Scopus and Embase databases up to 30th May 2021. Data have been extracted according to three categories: (1) patients' characteristics, (2) clinical and immunological responses to CP therapy and (3) pre-infusion screening of the CP samples.

RESULTS

A total of 12,553 articles were identified. One hundred fifty-four studies met the inclusion criteria for full-text review. More than half of the included studies (112 studies, (75.6%)) concluded satisfactory outcomes and or safety of CP infusion in patients. Results of studies showed the efficacy of CP therapy in clinical improvement (101 studies), decreasing in the level of inflammatory factors (62 studies), elimination or decreasing in viral load (60 studies), and induction or increase in antibody response (37 studies). Despite these promising results, the results of the 49 studies revealed that CP therapy was ineffective in the survival of patients, clinical improvement, viral infection elimination or decrease in the inflammatory factor levels. Furthermore, the adaptive immune response was evaluated in 3 studies. Information related to the pre-infusion screening for human leukocyte antigen/human neutrophil antigen (HLA/HNA) antibodies was not reported in most of the studies. Our gap analysis revealed that the influence of the CP infusion on the adaptive immune and inflammatory responses in patients with coronavirus needs further investigation.

CONCLUSIONS

Based on the results of most included studies, CP infusion was safe and resulted in clinical improvement of patients and decreasing the viral load. The effect of the CP infusion on adaptive immune response and inflammatory cytokines in patients with coronavirus needs further investigation.

An update on drugs with therapeutic potential for SARS-CoV-2 (COVID-19) treatment

The COVID-19 pandemic is one of the greatest threats to human health in the 21st century with more than 257 million cases and over 5.17 million deaths reported worldwide (as of November 23, 2021. Various agents were initially proclaimed to be effective against SARS-CoV-2, the etiological agent of COVID-19. Hydroxychloroquine, lopinavir/ritonavir, and ribavirin are all examples of therapeutic agents, whose efficacy against COVID-19 was later disproved. Meanwhile, concentrated efforts of researchers and clinicians worldwide have led to the identification of novel therapeutic options to control the disease including PAXLOVID™ (PF-07321332). Although COVID-19 cases are currently treated using a comprehensive approach of anticoagulants, oxygen, and antibiotics, the novel Pfizer agent PAXLOVID™ (PF-07321332), an investigational COVID-19 oral antiviral candidate, significantly reduced hospitalization time and death rates, based on an interim analysis of the phase 2/3 EPIC-HR (Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients) randomized, double-blind study of non-hospitalized adult patients with COVID-19, who are at high risk of progressing to severe illness. The scheduled interim analysis demonstrated an 89 % reduction in risk of COVID-19-related hospitalization or death from any cause compared to placebo in patients treated within three days of symptom onset (primary endpoint). However, there still exists a great need for the development of additional treatments, as the recommended therapeutic options are insufficient in many cases. Thus far, mRNA and vector vaccines appear to be the most effective modalities to control the pandemic. In the current review, we provide an update on the progress that has been made since April 2020 in clinical trials concerning the effectiveness of therapies available to combat COVID-19. We focus on currently recommended therapeutic agents, including steroids, various monoclonal antibodies, remdesivir, baricitinib, anticoagulants and PAXLOVID™ summarizing the latest original studies and meta-analyses. Moreover, we aim to discuss other currently and previously studied agents targeting COVID-19 that either show no or only limited therapeutic activity. The results of recent studies report that hydroxychloroquine and convalescent plasma demonstrate no efficacy against SARS-CoV-2 infection. Lastly, we summarize the studies on various drugs with incoherent or insufficient data concerning their effectiveness, such as amantadine, ivermectin, or niclosamide.

Myocarditis associated with Covid-19 disease: A systematic review of published case reports and case series

BACKGROUND

Covid-19 is an extremely contagious illness caused by the severe acute respiratory syndrome (SARS-CoV-2) virus. The cardiac involvement in such a public health emergency disease has not been well studied and a conflicting evidence exists on this issue.

OBJECTIVE

This systematic review article aimed to compile and illustrate clinical characteristics, diagnostic findings, management, and outcomes manifesting in myocarditis linked with Covid-19.

METHODS

A literature search was accomplished for published eligible articles with MEDLINE/PubMed and Embase databases. All eligible case reports and case series were included from around the world without any language restrictions. For this review, inclusion criteria were laboratory-confirmed SARS-CoV-2 infection cases reporting a diagnosis of acute myocarditis.

RESULTS

Data from 41 studies describing myocarditis in 42 Covid-19 patients was obtained. The median age of these patients was 43.4 years, with 71.4% of them being men. Fever was the most prevalent presenting symptoms seen in 57% of patients. Hypertension was the most pervasive comorbidity accompanying these patients. Cardiac biomarkers troponin and brain natriuretic peptide (BNP) were raised in almost 90% and 87% of patients, respectively. Electrocardiogram findings were nonspecific and included ST-segment and T-wave changes. Echocardiogram commonly showed left ventricular systolic dysfunction with increased heart size. Cardiac magnetic resonance imaging (CMRI) exhibited myocardial edema and injury. The most prevalent histopathological feature appreciated was diffuse lymphocytic inflammatory infiltrates. Antivirals and corticosteroids were the most frequently used medications. About 38% of patients also needed vasopressor assistance. Out of 42 patients, 67% recovered, and eight died.

CONCLUSION

Because of the risk of a sudden worsening of patients conditions and myocarditis association with considerable mortality and morbidity, a knowledge of this cardiac complication of Covid-19 disease is crucial for healthcare professionals.

The Effectiveness of Convalescent Plasma for the Treatment of Novel Corona Virus Disease 2019: A Systematic Review and Meta-Analysis

Background: Coronavirus disease 2019 (COVID-19), sweeping across the world, has created a worldwide pandemic. Effective treatments of COVID-19 are extremely urgent. Objective: To analyze the efficacy and safety of convalescent plasma (CCP) on patients with COVID-19. Methods: All the relevant studies were searched from PubMed, EMBASE,Cochrane library, Scopus, Web of Science, CBM, CNKI, Wan fang, VIP, Medrxiv, Biorxiv, and SSRN on July 19, 2021. PICOS criteria were as follows: (P) the study interests were human subjects with the infection of COVID-19; (I) the intervention of interest was CCP; (C) comparator treatments contained placebo, sham therapy, and standard treatment; (O) the primary outcome was mortality rates by the novel coronavirus. The secondary outcomes included the incidence of serious adverse events, the rate of ICU admission and mechanical ventilation (MV); the length of hospital stay; the duration of MV and ICU stay; the antibody levels, inflammatory factor levels, and viral loads. (S) Only randomized controlled trials (RCTs) of CCP were included. Subanalysis, quality assessment, sensitive analysis, and publication bias were conducted by two reviewers independently. Results: Sixteen RCTs were included and enrolled a total of 16,296 participants in this meta-analysis. The pooled data showed that no significant difference was observed in reducing the rate of overall mortality between CCP treatment group and placebo group (OR 0.96; 95% CI 0.90 to 1.03; p = 0.30; I 2 = 6%). According to the results of subgroup analysis, severe or critical patients with CCP showed significant difference in reducing the 28-day mortality of compared with placebo (OR 0.58, 95% CI 0.36 to 0.93, p = 0.02, I 2 = 0%). CCP groups have a significantly shorter duration of MV compared with the control group (weighted MD -1.00, 95% CI -1.86 to -0.14 d p = 0.02, I 2 = 0%). No significant difference was observed in the length of hospital stay, the duration of ICU, and the rate of ICU and MV. There is no conclusive evidence about the safety of CCP. Conclusion: Convalescent plasma can significantly reduce the 28-day mortality of severe or critical COVID-19 patients and the duration of MV. However, more evidence was needed to prove the safety of convalescent plasma.

Kinetics of Nucleocapsid, Spike and Neutralizing Antibodies, and Viral Load in Patients with Severe COVID-19 Treated with Convalescent Plasma

COVID-19 is an ongoing pandemic with high morbidity and mortality. Despite meticulous research, only dexamethasone has shown consistent mortality reduction. Convalescent plasma (CP) infusion might also develop into a safe and effective treatment modality on the basis of recent studies and meta-analyses; however, little is known regarding the kinetics of antibodies in CP recipients. To evaluate the kinetics, we followed 31 CP recipients longitudinally enrolled at a median of 3 days post symptom onset for changes in binding and neutralizing antibody titers and viral loads. Antibodies against the complete trimeric Spike protein and the receptor-binding domain (Spike-RBD), as well as against the complete Nucleocapsid protein and the RNA binding domain (N-RBD) were determined at baseline and weekly following CP infusion. Neutralizing antibody (pseudotype NAb) titers were determined at the same time points. Viral loads were determined semi-quantitatively by SARS-CoV-2 PCR. Patients with low humoral responses at entry showed a robust increase of antibodies to all SARS-CoV-2 proteins and Nab, reaching peak levels within 2 weeks. The rapid increase in binding and neutralizing antibodies was paralleled by a concomitant clearance of the virus within the same timeframe. Patients with high humoral responses at entry demonstrated low or no further increases; however, virus clearance followed the same trajectory as in patients with low antibody response at baseline. Together, the sequential immunological and virological analysis of this well-defined cohort of patients early in infection shows the presence of high levels of binding and neutralizing antibodies and potent clearance of the virus.

Safety and Efficacy of Convalescent Plasma in COVID-19: An Overview of Systematic Reviews

Convalescent plasma (CP) from patients recovered from COVID-19 is one of the most studied anti-viral therapies against SARS-COV-2 infection. The aim of this study is to summarize the evidence from the available systematic reviews on the efficacy and safety of CP in COVID-19 through an overview of the published systematic reviews (SRs). A systematic literature search was conducted up to August 2021 in Embase, PubMed, Web of Science, Cochrane and Medrxiv databases to identify systematic reviews focusing on CP use in COVID-19. Two review authors independently evaluated reviews for inclusion, extracted data and assessed quality of evidence using AMSTAR (A Measurement Tool to Assess Reviews) and GRADE tools. The following outcomes were analyzed: mortality, viral clearance, clinical improvement, length of hospital stay, adverse reactions. In addition, where possible, subgroup analyses were performed according to study design (e.g., RCTs vs. non-RCTs), CP neutralizing antibody titer and timing of administration, and disease severity. The methodological quality of included studies was assessed using the checklist for systematic reviews AMSTAR-2 and the GRADE assessment. Overall, 29 SRs met the inclusion criteria based on 53 unique primary studies (17 RCT and 36 non-RCT). Limitations to the methodological quality of reviews most commonly related to absence of a protocol (11/29) and funding sources of primary studies (27/29). Of the 89 analyses on which GRADE judgements were made, effect estimates were judged to be of high/moderate certainty in four analyses, moderate in 38, low in 38, very low in nine. Despite the variability in the certainty of the evidence, mostly related to the risk of bias and inconsistency, the results of this umbrella review highlight a mortality reduction in CP over standard therapy when administered early and at high titer, without increased adverse reactions.

Pandemics Throughout the History

As we move amidst the coronavirus disease 2019 (COVID-19) pandemic, we have witnessed tremendous distress, death, and turmoil of everyday life for more than one year now. However, they are not modern phenomena; deadly pandemics have happened throughout recorded history. Pandemics such as the plague, Spanish Flu, HIV, and Ebola caused deaths, destruction of political regimes, as well as financial and psychosocial burdens. However, they sometimes resulted in scientific discoveries. Understanding the mechanism of the emergence of these pandemics is crucial to control any spreading pandemic and prevent the emergence of a potential new one. Public health agencies need to work on improving the countries' pandemic preparedness to prevent any future pandemics. The review article aims to shed light on some of the deadliest pandemics throughout history, information of critical importance for clinicians and researchers.

Vaccine Development Throughout History

The emergence of the coronavirus disease 2019 (COVID-19) pandemic has made us appreciate how important it is to quickly develop treatments and save lives. The race to develop a vaccine for this novel coronavirus began as soon as the pandemic emerged. Time was the only limiting factor. From the first vaccine developed in 1796 against smallpox to the latest COVID-19 vaccine, there have been several vaccines that have reduced the burden of disease, with the associated mortality and morbidity. Over the years we have seen many new advancements in organism isolation, cell culture, whole-genome sequencing, and recombinant nuclear techniques. These techniques have greatly facilitated the development of vaccines. Each vaccine has its own development story and there is much wisdom to be gained from learning about breakthroughs in vaccine development.