Clinical Severity of Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Relative to Delta in British Columbia, Canada: A Retrospective Analysis of Whole-Genome Sequenced Cases

A cohort study of patients hospitalised with SARS-CoV-2 infection in Ontario: patient characteristics and outcomes by wave

INTRODUCTION

Each wave of the COVID-19 pandemic exhibited a unique combination of epidemiological, social and structural characteristics. We explore similarities and differences in wave-over-wave characteristics of patients hospitalised with COVID-19.

METHODS

This was a population-based study in Ontario province, Canada. Patients hospitalised with SARS-CoV-2 between 26 February 2020 and 31 March 2022 were included. An admission was considered related to SARS-CoV-2 infection if the provincial inpatient or outpatient hospital databases contained the ICD-10 diagnostic codes U071/U072 or the Ontario Laboratories Information System indicated a positive SARS-CoV-2 test result (PCR or rapid antigen testing) during the admission or up to two weeks prior. The primary outcome was 90-day mortality (modified Poisson regression). Secondary outcomes were use of critical care during the admission (logistic regression) and total length-of-stay (linear regression with heteroskedastic-consistent standard-error estimators). All models were adjusted for demographic characteristics, neighbourhood socioeconomic factors and indicators of illness severity.

RESULTS

There were 73,201 SARS-CoV-2-related admissions: 6127 (8%) during wave 1 (wild-type), 14,371 (20%) during wave 2 (wild-type), 16,653 (23%) during wave 3 (Alpha), 5678 (8%) during wave 4 (Delta) and 30,372 (42%) during wave 5 (Omicron). SARS-CoV-2 was the most responsible diagnosis for 70% of admissions during waves 1-2 and 42% in wave 5. The proportion of admitted patients who were long-term care residents was 18% (n = 1111) during wave 1, decreasing to 10% (n = 1468) in wave 2 and <5% in subsequent waves. During waves 1-3, 46% of all admitted patients resided in a neighbourhood assigned to the highest ethnic diversity quintile, which declined to 27% during waves 4-5. Compared to wave 1, 90-day mortality was similar during wave 2 (adjusted risk ratio [aRR]: 1.00 [95% CI: 0.95-1.04]), but lower during wave 3 (aRR: 0.89 [0.85-0.94]), wave 4 (aRR: 0.85 [0.79-0.91]) and wave 5 (aRR: 0.83 [0.80-0.88]). Improvements in survival over waves were observed among elderly patients (p-interaction <0.0001). Critical care admission was significantly less likely during wave 5 than previous waves (adjusted odds ratio: 0.50 [0.47-0.54]). The length of stay was a median of 8.5 (3.6-23.8) days during wave 1 and 5.3 (2.2-12.6) during wave 5. After adjustment, the mean length of stay was on average -10.4 (-11.1 to -9.8) days, i.e. shorter, in wave 5 vs wave 1.

CONCLUSION

Throughout the pandemic, sociodemographic characteristics of patients hospitalised with SARS-CoV-2 changed over time, particularly in terms of ethnic diversity, but still disproportionately affected patients from more marginalised regions. Improved survival and reduced use of critical care during the Omicron wave are reassuring.

Comparing COVID-19 severity in patients hospitalized for community-associated Delta, BA.1 and BA.4/5 variant infection

Background

Despite decreasing COVID-19 disease severity during the Omicron waves, a proportion of patients still require hospitalization and intensive care.

Objective

To compare demographic characteristics, comorbidities, vaccination status, and previous infections in patients hospitalized for community-associated COVID-19 (CAC) in predominantly Delta, Omicron BA.1 and BA.4/5 SARS-CoV-2 waves.

Methods

Data were extracted from three national databases-the National COVID-19 Database, National Vaccination Registry and National Registry of Hospitalizations.

Results

Among the hospitalized CAC patients analyzed in this study, 5,512 were infected with Delta, 1,120 with Omicron BA.1, and 1,143 with the Omicron BA.4/5 variant. The age and sex structure changed from Delta to BA.4/5, with the proportion of women (9.5% increase), children and adolescents (10.4% increase), and octa- and nonagenarians increasing significantly (24.5% increase). Significantly more patients had comorbidities (measured by the Charlson Comorbidity Index), 30.3% in Delta and 43% in BA.4/5 period. The need for non-invasive ventilatory support (NiVS), ICU admission, mechanical ventilation (MV), and in-hospital mortality (IHM) decreased from Delta to Omicron BA.4/5 period for 12.6, 13.5, 11.5, and 6.3%, respectively. Multivariate analysis revealed significantly lower odds for ICU admission (OR 0.68, CI 0.54-0.84, p < 0.001) and IHM (OR 0.74, CI 0.58-0.93, p = 0.011) during the Delta period in patients who had been fully vaccinated or boosted with a COVID-19 vaccine within the previous 6 months. In the BA.1 variant period, patients who had less than 6 months elapsed between the last vaccine dose and SARS-CoV-2 positivity had lower odds for MV (OR 0.38, CI 0.18-0.72, p = 0.005) and IHM (OR 0.56, CI 0.37- 0.83, p = 0.005), but not for NIVS or ICU admission.

Conclusion

The likelihood of developing severe CAC in hospitalized patients was higher in those with the Delta and Omicron BA.1 variant compared to BA.4/5.

Cohort profile: the British Columbia COVID-19 Cohort (BCC19C)-a dynamic, linked population-based cohort

Purpose

The British Columbia COVID-19 Cohort (BCC19C) was developed from an innovative, dynamic surveillance platform and is accessed/analyzed through a cloud-based environment. The platform integrates recently developed provincial COVID-19 datasets (refreshed daily) with existing administrative holdings and provincial registries (refreshed weekly/monthly). The platform/cohort were established to inform the COVID-19 response in near "real-time" and to answer more in-depth epidemiologic questions.

Participants

The surveillance platform facilitates the creation of large, up-to-date analytic cohorts of people accessing COVID-19 related services and their linked medical histories. The program of work focused on creating/analyzing these cohorts is referred to as the BCC19C. The administrative/registry datasets integrated within the platform are not specific to COVID-19 and allow for selection of "control" individuals who have not accessed COVID-19 services.

Findings to date

The platform has vastly broadened the range of COVID-19 analyses possible, and outputs from BCC19C analyses have been used to create dashboards, support routine reporting and contribute to the peer-reviewed literature. Published manuscripts (total of 15 as of July, 2023) have appeared in high-profile publications, generated significant media attention and informed policy and programming. In this paper, we conducted an analysis to identify sociodemographic and health characteristics associated with receiving SARS-CoV-2 laboratory testing, testing positive, and being fully vaccinated. Other published analyses have compared the relative clinical severity of different variants of concern; quantified the high "real-world" effectiveness of vaccines in addition to the higher risk of myocarditis among younger males following a 2nd dose of an mRNA vaccine; developed and validated an algorithm for identifying long-COVID patients in administrative data; identified a higher rate of diabetes and healthcare utilization among people with long-COVID; and measured the impact of the pandemic on mental health, among other analyses.

Future plans

While the global COVID-19 health emergency has ended, our program of work remains robust. We plan to integrate additional datasets into the surveillance platform to further improve and expand covariate measurement and scope of analyses. Our analyses continue to focus on retrospective studies of various aspects of the COVID-19 pandemic, as well as prospective assessment of post-acute COVID-19 conditions and other impacts of the pandemic.

Risk of hospital admission and death from first-ever SARS-CoV-2 infection by age group during the Delta and Omicron periods in British Columbia, Canada

BACKGROUND

Population-based cross-sectional serosurveys within the Lower Mainland, British Columbia, Canada, showed about 10%, 40% and 60% of residents were infected with SARS-CoV-2 by the sixth (September 2021), seventh (March 2022) and eighth (July 2022) serosurveys. We conducted the ninth (December 2022) and tenth (July 2023) serosurveys and sought to assess risk of severe outcomes from a first-ever SARS-CoV-2 infection during intersurvey periods.

METHODS

Using increments in cumulative infection-induced seroprevalence, population census, discharge abstract and vital statistics data sets, we estimated infection hospitalization and fatality ratios (IHRs and IFRs) by age and sex for the sixth to seventh (Delta/Omicron-BA.1), seventh to eighth (Omicron-BA.2/BA.5) and eighth to ninth (Omicron-BA.5/BQ.1) intersurvey periods. As derived, IHR and IFR estimates represent the risk of severe outcome from a first-ever SARS-CoV-2 infection acquired during the specified intersurvey period.

RESULTS

The cumulative infection-induced seroprevalence was 74% by December 2022 and 79% by July 2023, exceeding 80% among adults younger than 50 years but remaining less than 60% among those aged 80 years and older. Period-specific IHR and IFR estimates were consistently less than 0.3% and 0.1% overall. By age group, IHR and IFR estimates were less than 1.0% and up to 0.1%, respectively, except among adults aged 70-79 years during the sixth to seventh intersurvey period (IHR 3.3% and IFR 1.0%) and among those aged 80 years and older during all periods (IHR 4.7%, 2.2% and 3.5%; IFR 3.3%, 0.6% and 1.3% during the sixth to seventh, seventh to eighth and eighth to ninth periods, respectively). The risk of severe outcome followed a J-shaped age pattern. During the eighth to ninth period, we estimated about 1 hospital admission for COVID-19 per 300 newly infected children younger than 5 years versus about 1 per 30 newly infected adults aged 80 years and older, with no deaths from COVID-19 among children but about 1 death per 80 newly infected adults aged 80 years and older during that period.

INTERPRETATION

By July 2023, we estimated about 80% of residents in the Lower Mainland, BC, had been infected with SARS-CoV-2 overall, with low risk of hospital admission or death; about 40% of the oldest adults, however, remained uninfected and at highest risk of a severe outcome. First infections among older adults may still contribute substantial burden from COVID-19, reinforcing the need to continue to prioritize this age group for vaccination and to consider them in health care system planning.

Risk of COVID-19 hospitalization in people living with HIV and HIV-negative individuals and the role of COVID-19 vaccination: A retrospective cohort study

OBJECTIVE

To examine the risk of hospitalization within 14 days of COVID-19 diagnosis among people living with HIV (PLWH) and HIV-negative individuals who had laboratory-confirmed SARS-CoV-2 infection.

METHODS

We used Cox proportional hazard models to compare the relative risk of hospitalization in PLWH and HIV-negative individuals. Then, we used propensity score weighting to examine the influence of sociodemographic factors and comorbid conditions on risk of hospitalization. These models were further stratified by vaccination status and pandemic period (pre-Omicron: December 15, 2020, to November 21, 2021; Omicron: November 22, 2021, to October 31, 2022).

RESULTS

The crude hazard ratio (HR) for risk of hospitalization in PLWH was 2.44 (95% confidence interval [CI]: 2.04-2.94). In propensity score-weighted models that included all covariates, the relative risk of hospitalization was substantially attenuated in the overall analyses (adjusted HR [aHR]: 1.03; 95% CI: 0.85-1.25), in vaccinated (aHR 1.00; 95% CI: 0.69-1.45), inadequately vaccinated (aHR: 1.04; 95% CI: 0.76-1.41) and unvaccinated individuals (aHR: 1.15; 95% CI: 0.84-1.56).

CONCLUSION

PLWH had about two times the risk of COVID-19 hospitalization than HIV-negative individuals in crude analyses which attenuated in propensity score-weighted models. This suggests that the risk differential can be explained by sociodemographic factors and history of comorbidity, underscoring the need to address social and comorbid vulnerabilities (e.g., injecting drugs) that were more prominent among PLWH.

Patients Hospitalized for COVID-19 in the Periods of Delta and Omicron Variant Dominance in Greece: Determinants of Severity and Mortality

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been a pandemic since 2020, and depending on the SARS-CoV-2 mutation, different pandemic waves have been observed. The aim of this study was to compare the baseline characteristics of patients in two phases of the pandemic and evaluate possible predictors of mortality.

METHODS

This is a retrospective multicenter observational study that included patients with COVID-19 in 4 different centers in Greece. Patients were divided into two groups depending on the period during which they were infected during the Delta and Omicron variant predominance.

RESULTS

A total of 979 patients (433 Delta, 546 Omicron) were included in the study (median age 67 years (54, 81); 452 [46.2%] female). Compared to the Omicron period, the patients during the Delta period were younger (median age [IQR] 65 [51, 77] vs. 70 [55, 83] years, p < 0.001) and required a longer duration of hospitalization (8 [6, 13] vs. 7 [5, 12] days, p = 0.001), had higher procalcitonin levels (ng/mL): 0.08 [0.05, 0.17] vs. 0.06 [0.02, 0.16], p = 0.005, ferritin levels (ng/mL): 301 [159, 644] vs. 239 [128, 473], p = 0.002, C- reactive protein levels (mg/L): 40.4 [16.7, 98.5] vs. 31.8 [11.9, 81.7], p = 0.003, and lactate dehydrogenase levels (U/L): 277 [221, 375] vs. 255 [205, 329], p < 0.001. The Charlson Comorbidity Index was lower (3 [0, 5] vs. 4 [1, 6], p < 0.001), and the extent of disease on computed tomography (CT) was greater during the Delta wave (p < 0.001). No evidence of a difference in risk of death or admission to the intensive care unit was found between the two groups. Age, cardiovascular events, acute kidney injury during hospitalization, extent of disease on chest CT, D-dimer, and neutrophil/lymphocyte ratio values were identified as independent predictors of mortality for patients in the Delta period. Cardiovascular events and acute liver injury during hospitalization and the PaO2/FiO2 ratio on admission were identified as independent predictors of mortality for patients in the Omicron period.

CONCLUSIONS

In the Omicron wave, patients were older with a higher number of comorbidities, but patients with the Delta variant had more severe disease and a longer duration of hospitalization.

Diminished Neutralization Capacity of SARS-CoV-2 Omicron BA.1 in Donor Plasma Collected from January to March 2021

The 50% plaque reduction neutralization assay (PRNT50) has been previously used to assess the neutralization capacity of donor plasma against wild-type and variant of concern (VOC) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging data suggest that plasma with an anti-SARS-CoV-2 level of ≥2 × 104 binding antibody units/mL (BAU/mL) protects against SARS-CoV-2 Omicron BA.1 infection. Specimens were collected using a cross-sectional random sampling approach. For PRNT50 studies, 63 previously analyzed specimens by PRNT50 versus SARS-CoV-2 wild-type, Alpha, Beta, Gamma, and Delta were analyzed by PRNT50 versus Omicron BA.1. The 63 specimens plus 4,390 specimens (randomly sampled regardless of serological evidence of infection) were also tested using the Abbott SARS-CoV-2 IgG II Quant assay (anti-spike [S]; Abbott, Chicago, IL, USA; Abbott Quant assay). In the vaccinated group, the percentages of specimens with any measurable PRNT50 versus wild-type or VOC were wild type (21/25 [84%]), Alpha (19/25 [76%]), Beta (18/25 [72%]), Gamma (13/25 [52%]), Delta (19/25 [76%]), and Omicron BA.1 (9/25 [36%]). In the unvaccinated group, the percentages of specimens with any measurable PRNT50 versus wild type or VOC were wild-type SARS-CoV-2 (16/39 [41%]), Alpha (16/39 [41%]), Beta (10/39 [26%]), Gamma (9/39 [23%]), Delta (16/39 [41%]), and Omicron BA.1 (0/39) (Fisher's exact tests, vaccinated versus unvaccinated for each variant, P < 0.05). None of the 4,453 specimens tested by the Abbott Quant assay had a binding capacity of ≥2 × 104 BAU/mL. Vaccinated donors were more likely than unvaccinated donors to neutralize Omicron when assessed by a PRNT50 assay. IMPORTANCE SARS-CoV-2 Omicron emergence occurred in Canada during the period from November 2021 to January 2022. This study assessed the ability of donor plasma collected earlier (January to March 2021) to generate any neutralizing capacity against Omicron BA.1 SARS-CoV-2. Vaccinated individuals, regardless of infection status, were more likely to neutralize Omicron BA.1 than unvaccinated individuals. This study then used a semiquantitative binding antibody assay to screen a larger number of specimens (4,453) for individual specimens that might have high-titer neutralizing capacity against Omicron BA.1. None of the 4,453 specimens tested by the semiquantitative SARS-CoV-2 assay had a binding capacity suggestive of a high-titer neutralizing capacity against Omicron BA.1. These data do not imply that Canadians lacked immunity to Omicron BA.1 during the study period. Immunity to SARS-CoV-2 is complex, and there is still no wide consensus on correlation of protection to SARS-CoV-2.

Assessment of clinical characteristics and viral load in individuals infected by Delta and Omicron variants of SARS-CoV-2

In late 2021, a new variant of SARS-CoV-2 called Omicron emerged, replacing Delta worldwide. Although it has been associated with a lower risk of hospitalization and severe forms of COVID-19, there is little evidence of its relationship with specific symptoms and viral load. The aim of this study was to verify the relationship between Delta and Omicron variants of concern, viral load, and the occurrence of symptoms in individuals with COVID-19. Nasopharyngeal swab samples were collected and sequenced from patients with COVID-19 from the Northeast Region of Brazil between August 2021 and March 2022. The results showed a gradual replacement of the Delta variant by the Omicron variant during the study period. A total of 316 samples (157 Delta and 159 Omicron) were included. There was a higher prevalence of symptoms in Delta-infected individuals, such as coryza, olfactory and taste disturbances, headache, and myalgia. There was no association between viral load and the variants analyzed. The results reported here contribute to the understanding of the symptoms associated with the Delta and Omicron variants in individuals affected by COVID-19.

Factors associated with COVID-19 vaccination coverage in hypertensive patients with Omicron infection in Shanghai, China

The potential future burden of COVID-19 is determined by the level of susceptibility of the population to infection. The protective effect provided by those previously infected diminishes over several months, while individuals with mixed immunity have the highest degree and persistence of protection. This study aimed to clarify the vaccination status of COVID-19 patients with hypertension and to analyze the characteristics and risk factors of non-vaccinated patients to protect this vulnerable population in the future. The study ultimately enrolled 4576 hypertensive patients with Omicron infection from April 6, 2022, to May 15, 2022. Among them, 3556 patients (77.7%) had received at least one dose of vaccine, and 2058 patients (45.0%) received a booster dose. In the multivariate logistic analysis, male (OR 1.328, 95% CI 1.138-1.550, p < .001), age (60-69 years vs.18-49 years) (OR 0.348, 95% CI 0.270-0.448, p < .001), age (≥70 years vs.18-49 years) (OR 0.130, 95% CI 0.100-0.169, p < .001), diabetes mellitus (OR 0.553, 95% CI 0.463-0.661, p < .001), chronic pulmonary diseases (OR 0.474, 95% CI 0.260-0.863, p = .015), chronic kidney disease (OR 0.177, 95% CI 0.076-0.410, p < .001), and cancer (OR 0.225, 95% CI 0.094-0.535, p = .001) were associated with vaccinated status. The vaccine coverage rate, especially the booster vaccine, was low for hypertensive patients with Omicron infection. Females, increasing age, and coexisting chronic diseases were associated with more inadequate vaccine coverage in hypertensive COVID-19 patients. Targeted interventions are required to address the under-vaccination of diverse hypertensive populations.

Complement and COVID-19: Three years on, what we know, what we don't know, and what we ought to know

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus was identified in China in 2019 as the causative agent of COVID-19, and quickly spread throughout the world, causing over 7 million deaths, of which 2 million occurred prior to the introduction of the first vaccine. In the following discussion, while recognising that complement is just one of many players in COVID-19, we focus on the relationship between complement and COVID-19 disease, with limited digression into directly-related areas such as the relationship between complement, kinin release, and coagulation. Prior to the 2019 COVID-19 outbreak, an important role for complement in coronavirus diseases had been established. Subsequently, multiple investigations of patients with COVID-19 confirmed that complement dysregulation is likely to be a major driver of disease pathology, in some, if not all, patients. These data fuelled evaluation of many complement-directed therapeutic agents in small patient cohorts, with claims of significant beneficial effect. As yet, these early results have not been reflected in larger clinical trials, posing questions such as who to treat, appropriate time to treat, duration of treatment, and optimal target for treatment. While significant control of the pandemic has been achieved through a global scientific and medical effort to comprehend the etiology of the disease, through extensive SARS-CoV-2 testing and quarantine measures, through vaccine development, and through improved therapy, possibly aided by attenuation of the dominant strains, it is not yet over. In this review, we summarise complement-relevant literature, emphasise its main conclusions, and formulate a hypothesis for complement involvement in COVID-19. Based on this we make suggestions as to how any future outbreak might be better managed in order to minimise impact on patients.

Clinical severity of Omicron subvariants BA.1, BA.2, and BA.5 in a population-based cohort study in British Columbia, Canada

The SARS-CoV-2 variant Omicron emerged in late 2021. In British Columbia (BC), Canada, and globally, three genetically distinct subvariants of Omicron, BA.1, BA.2, and BA.5, emerged and became dominant successively within an 8-month period. SARS-CoV-2 subvariants continue to circulate in the population, acquiring new mutations that have the potential to alter infectivity, immunity, and disease severity. Here, we report a propensity-matched severity analysis from residents of BC over the course of the Omicron wave, including 39,237 individuals infected with BA.1, BA.2, or BA.5 based on paired high-quality sequence data and linked to comprehensive clinical outcomes data between December 23, 2021 and August 31, 2022. Relative to BA.1, BA.2 cases were associated with a 15% and 28% lower risk of hospitalization and intensive care unit (ICU) admission (aHR_hospital  = 1.17; 95% confidence interval [CI] = 1.096-1.252; aHR_ICU  = 1.368; 95% CI = 1.152-1.624), whereas BA.5 infections were associated with an 18% higher risk of hospitalization (aHR_hospital  = 1.18; 95% CI = 1.133-1.224) after accounting for age, sex, comorbidities, vaccination status, geography, and social determinants of health. Phylogenetic analysis revealed no specific subclades associated with more severe clinical outcomes for any Omicron subvariant. In summary, BA.1, BA.2, and BA.5 subvariants were associated with differences in clinical severity, emphasizing how variant-specific monitoring programs remain critical components of patient and population-level public health responses as the pandemic continues.

Value of Laboratory Indicators in Predicting Pneumonia in Symptomatic COVID-19 Patients Infected with the SARS-CoV-2 Omicron Variant

Background

The pathogenicity of Omicron is different from that of the previous strains. The value of hematological indicators in patients at high risk of Omicron infection remains unclear. We need rapid, inexpensive and widely available biomarkers to guide the early detection of people at risk of pneumonia and to provide early intervention. We aimed to assess the value of hematological indicators as risk factors for pneumonia in symptomatic COVID-19 patients infected with the SARS-CoV-2 Omicron variant.

Patients and Methods

The study enrolled 144 symptomatic COVID-19 patients with Omicron infection. We collected available clinical details, including laboratory tests and CT examinations. Univariate and multivariate logistic analyses and receiver operating characteristic (ROC) curve analyses were used to assess the value of laboratory markers in predicting the development of pneumonia.

Results

Among the 144 patients, 50 (34.7%) had pneumonia. The ROC analysis revealed that the areas under the ROC curve (AUC) for leukocytes, lymphocytes, neutrophils, and fibrinogen were 0.603 (95% confidence interval (CI): 0.501-0.704, P=0.043), 0.615 (95% CI: 0.517-0.712, P=0.024), 0.632 (95% CI: 0.534-0.730, P=0.009) and 0.635 (95% CI: 0.539-0.730, P=0.008), respectively. The AUC for neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR), fibrinogen to lymphocyte ratio (FLR), and fibrinogen to D-dimer ratio (FDR) were 0.670 (95% CI: 0.580-0.760, P=0.001), 0.632 (95% CI: 0.535-0.728, P=0.009), 0.669 (95% CI: 0.575-0.763, P=0.001) and 0.615 (95% CI: 0.510-0.721, P=0.023), respectively. Univariate analysis showed that elevated levels of NLR (odds ratio (OR): 1.219, 95% CI: 1.046-1.421, P=0.011), FLR (OR: 1.170, 95% CI: 1.014-1.349, P=0.031) and FDR (OR: 1.131, 95% CI: 1.039-1.231, P=0.005) were significantly correlated with the presence of pneumonia. Multivariate analysis indicated elevated NLR (OR: 1.248, 95% CI: 1.068-1.459, P=0.005) and FDR (OR: 1.160, 95% CI: 1.054-1.276, P=0.002) levels were associated with the existence of pneumonia. The AUC for the combination of NLR and FDR was 0.701 (95% CI: 0.606-0.796, P<0.001, sensitivity 56.0%, specificity 83.0%).

Conclusion

NLR and FDR can predict the presence of pneumonia in symptomatic COVID-19 patients infected with the SARS-CoV-2 Omicron variant.

Nanomaterials to combat SARS-CoV-2: Strategies to prevent, diagnose and treat COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the associated coronavirus disease 2019 (COVID-19), which severely affect the respiratory system and several organs and tissues, and may lead to death, have shown how science can respond when challenged by a global emergency, offering as a response a myriad of rapid technological developments. Development of vaccines at lightning speed is one of them. SARS-CoV-2 outbreaks have stressed healthcare systems, questioning patients care by using standard non-adapted therapies and diagnostic tools. In this scenario, nanotechnology has offered new tools, techniques and opportunities for prevention, for rapid, accurate and sensitive diagnosis and treatment of COVID-19. In this review, we focus on the nanotechnological applications and nano-based materials (i.e., personal protective equipment) to combat SARS-CoV-2 transmission, infection, organ damage and for the development of new tools for virosurveillance, diagnose and immune protection by mRNA and other nano-based vaccines. All the nano-based developed tools have allowed a historical, unprecedented, real time epidemiological surveillance and diagnosis of SARS-CoV-2 infection, at community and international levels. The nano-based technology has help to predict and detect how this Sarbecovirus is mutating and the severity of the associated COVID-19 disease, thereby assisting the administration and public health services to make decisions and measures for preparedness against the emerging variants of SARS-CoV-2 and severe or lethal COVID-19.

Old Age is an Independent Risk Factor for Pneumonia Development in Patients with SARS-CoV-2 Omicron Variant Infection and a History of Inactivated Vaccine Injection

Objective

Analyzing the risk factors for pneumonia development in breakthrough cases with a history of inactivated vaccine injection is important. The present study aimed to investigate the risk factors for pneumonia development during Omicron variant infection.

Design and Methods

The clinical data were retrospectively collected from 187 patients who previously received inactivated vaccine and were infected by the Omicron variant.

Results

Among the 187 patients, 73 had 2 doses of inactivated vaccine injection and the remaining 114 had 3 doses; 19 patients had pneumonia at admission. The univariate logistic analysis showed that age, baseline platelet count, D-dimer level, and CD8⁺ T lymphocyte count were associated with pneumonia development at admission. The multivariate analysis showed that only age was the independent risk factor for pneumonia development (odds ratio = 1.046, 95% confidence interval: 1.003-1.091, P = 0.04). With an optimal cutoff value of 46, 4.4% (4/91) patients in the age <46 years group and 15.63% (15/96) patients in the age ≥46 years group had pneumonia (χ ² = 6.454, P = 0.01). Moreover, age negatively correlated with CD8⁺ T cell count, B cell count, and albumin and uric acid levels (all P < 0.01), while age positively correlated with the glucose level (P < 0.01).

Conclusion

Old age was the only independent risk factor for pneumonia development in patients with Omicron variant infection and a history of inactivated vaccine injection.