Transmissibility, hospitalization, and intensive care admissions due to omicron compared to delta variants of SARS-CoV-2 in Catalonia: A cohort study and ecological analysis

From Entry to Outbreak in a High School Setting: Clinical and Wastewater Surveillance of a Rare SARS-CoV-2 Variant

In December 2021, an outbreak of the SARS-CoV-2 B.1.640.2 variant, potentially originating from Cameroon, was investigated among schoolchildren in Germany. The index case, an adult who had recently returned from a three-week stay in the Republic of Congo, introduced the variant into a school setting via their children, resulting in subsequent transmission within the school and ultimately to a hospital ward. Whole-genome sequencing of viral samples identified both B.1.640.1 and B.1.640.2 lineages. This outbreak highlights the unpredictable nature of emerging SARS-CoV-2 variants and emphasizes the importance of early detection and containment to mitigate transmission to high-risk populations. Notably, wastewater surveillance detected the variant during the study peri-od, reinforcing the utility of wastewater-based epidemiology as a complementary tool for the early warning and containment of novel variants. These findings underline the critical need for timely research and adherence to quarantine measures to enhance outbreak control efforts.

Impact of corticosteroid doses on prognosis of severe and critical COVID-19 patients with Omicron variant infection: a propensity score matching study

BACKGROUND

There is lack of research on corticosteroid use for severe and critical COVID-19 patients with Omicron variant infection.

METHODS

This multi-center retrospective cohort study involved 1167 patients from 59 ICUs across the mainland of China diagnosed with severe or critical SARS-CoV-2 Omicron variant infection between November 1, 2022, and February 11, 2023. Patients were segregated into two groups based on their corticosteroid treatment-usual dose (equivalent prednisone dose 30-50 mg/day) and higher dose (equivalent prednisone dose > 50 mg/day). The primary outcome was 28-day ICU mortality. Propensity score matching was used to compare outcomes between cohorts.

RESULTS

After propensity score matching, 520 patients in the usual dose corticosteroid group and 260 patients in the higher dose corticosteroid group were included in the analysis, respectively. The mortality was significantly higher in the higher dose corticosteroid group (67.3%, 175/260) compared to the usual dose group (56.0%, 291/520). Logistic regression showed that higher doses of corticosteroids were significantly associated with increased mortality at 28-day (OR = 1.62,95% CI 1.19-2.21, p = 0.002) and mortality in ICU stay (OR = 1.66,95% CI 1.21-2.28, p = 0.002). Different types of corticosteroids did not affect the effect.

CONCLUSIONS

The study suggests that higher-dose corticosteroids may lead to a poorer prognosis for severe and critical COVID-19 patients with Omicron variant infection in the ICU. Further research is needed to determine the appropriate corticosteroid dosage for these patients.

Severity of Omicron Subvariants and Vaccine Impact in Catalonia, Spain

In the current COVID-19 landscape dominated by Omicron subvariants, understanding the timing and efficacy of vaccination against emergent lineages is crucial for planning future vaccination campaigns, yet detailed studies stratified by subvariant, vaccination timing, and age groups are scarce. This retrospective study analyzed COVID-19 cases from December 2021 to January 2023 in Catalonia, Spain, focusing on vulnerable populations affected by variants BA.1, BA.2, BA.5, and BQ.1 and including two national booster campaigns. Our database includes detailed information such as dates of diagnosis, hospitalization and death, last vaccination, and cause of death, among others. We evaluated the impact of vaccination on disease severity by age, variant, and vaccination status, finding that recent vaccination significantly mitigated severity across all Omicron subvariants, although efficacy waned six months post-vaccination, except for BQ.1, which showed more stable levels. Unvaccinated individuals had higher hospitalization and mortality rates. Our results highlight the importance of periodic vaccination to reduce severe outcomes, which are influenced by variant and vaccination timing. Although the seasonality of COVID-19 is uncertain, our analysis suggests the potential benefit of annual vaccination in populations >60 years old, probably in early fall, if COVID-19 eventually exhibits a major peak similar to other respiratory viruses.

Risk of Arterial and Venous Thrombotic Events Among Patients with COVID-19: A Multi-National Collaboration of Regulatory Agencies from Canada, Europe, and United States

Purpose

Few studies have examined how the absolute risk of thromboembolism with COVID-19 has evolved over time across different countries. Researchers from the European Medicines Agency, Health Canada, and the United States (US) Food and Drug Administration established a collaboration to evaluate the absolute risk of arterial (ATE) and venous thromboembolism (VTE) in the 90 days after diagnosis of COVID-19 in the ambulatory (eg, outpatient, emergency department, nursing facility) setting from seven countries across North America (Canada, US) and Europe (England, Germany, Italy, Netherlands, and Spain) within periods before and during COVID-19 vaccine availability.

Patients and Methods

We conducted cohort studies of patients initially diagnosed with COVID-19 in the ambulatory setting from the seven specified countries. Patients were followed for 90 days after COVID-19 diagnosis. The primary outcomes were ATE and VTE over 90 days from diagnosis date. We measured country-level estimates of 90-day absolute risk (with 95% confidence intervals) of ATE and VTE.

Results

The seven cohorts included 1,061,565 patients initially diagnosed with COVID-19 in the ambulatory setting before COVID-19 vaccines were available (through November 2020). The 90-day absolute risk of ATE during this period ranged from 0.11% (0.09-0.13%) in Canada to 1.01% (0.97-1.05%) in the US, and the 90-day absolute risk of VTE ranged from 0.23% (0.21-0.26%) in Canada to 0.84% (0.80-0.89%) in England. The seven cohorts included 3,544,062 patients with COVID-19 during vaccine availability (beginning December 2020). The 90-day absolute risk of ATE during this period ranged from 0.06% (0.06-0.07%) in England to 1.04% (1.01-1.06%) in the US, and the 90-day absolute risk of VTE ranged from 0.25% (0.24-0.26%) in England to 1.02% (0.99-1.04%) in the US.

Conclusion

There was heterogeneity by country in 90-day absolute risk of ATE and VTE after ambulatory COVID-19 diagnosis both before and during COVID-19 vaccine availability.

Effects of entecavir and tenofovir disoproxil fumarate on the incidence and severity of COVID-19 in patients with chronic hepatitis B

BACKGROUND

Whether different anti-hepatitis B virus (HBV) drugs have different effects on COVID-19 is controversial. We aimed to evaluate the incidence of COVID-19 in chronic hepatitis B (CHB) patients receiving anti-HBV treatment, and to compare the impact of entecavir (ETV) and tenofovir disoproxil fumarate (TDF) on the severity of COVID-19.

METHODS

CHB outpatients were enrolled from December 2022 to February 2023. Questionnaires were used to collect whether subjects were currently or previously had COVID-19 within the past 2 months, and the information of symptoms, duration, and severity if infected.

RESULTS

Six hundred thirty CHB patients were enrolled, 64.3% (405/630) patients were currently or previously had COVID-19. No COVID-19 patient required hospitalization, intensive care unit admission, oxygen support or died. Majority of patients reported mild (32.8% [133/405]) and moderate (48.1% [195/405]) symptoms. After propensity score matching, 400 matched patients were obtained (ETV: 238; TDF: 162), among which the incidences of COVID-19 were comparable between ETV and TDF-treated patients (60.1% [143/238] vs. 64.2% [104/162], p = 0.468). The proportion of patients complicated with any symptom caused by COVID-19 were also similar (ETV vs. TDF: 90.9% [130/143] vs. 91.3% [95/104], p = 1.000). In addition, the severity of overall symptom was comparable between ETV and TDF-treated patients, in terms of proportion of patients complicated with severe symptom (9.8% vs. 8.7%, p = 0.989), symptom duration (4.3 vs. 4.3 days, p = 0.927), and symptom severity score (4.1 vs. 4.0, p = 0.758). Subgroup analysis supported these results.

CONCLUSIONS

During the current pandemic, the vast majority of CHB patients experienced non-severe COVID-19, and ETV and TDF did not affect COVID-19 severity differently.

Risk of partial school closure for COVID-19 by socio-economic level in the period 2020-22

BACKGROUND

The objective was to analyse the risk of partial school closure by economic level in Barcelona city.

METHODS

In this ecological study, the risk of partial school closure for the academic years 2020-21 and 2021-22 was estimated by dividing the total number of days that each child was in quarantine or isolation by the total number of days that each child was at risk to be in quarantine or isolation in the academic year. The association between partial school closure risk and mean income by district was estimated with the Spearman rho.

RESULTS

The lower the mean income, the higher the risk of partial closure (Spearman rho = 0.83; P-value = 0.003) during the academic year 2020-21. Specifically, the children from the district with the lowest income had a six times greater risk of partial school closure compared with those from the highest-income district. This risk did not show a significant socioeconomic gradient in the academic year 2021-22.

CONCLUSIONS

The risk of partial school closure presented an inverse socioeconomic gradient in the city of Barcelona according to average income by district in the academic year 2020-21. This distribution was not observed in the academic year 2021-22.

Comparing methods to classify admitted patients with SARS-CoV-2 as admitted for COVID-19 versus with incidental SARS-CoV-2: A cohort study

INTRODUCTION

Not all patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection develop symptomatic coronavirus disease 2019 (COVID-19), making it challenging to assess the burden of COVID-19-related hospitalizations and mortality. We aimed to determine the proportion, resource utilization, and outcomes of SARS-CoV-2 positive patients admitted for COVID-19, and assess the impact of using the Center for Disease Control's (CDC) discharge diagnosis-based algorithm and the Massachusetts state department's drug administration-based classification system on identifying admissions for COVID-19.

METHODS

In this retrospective cohort study, we enrolled consecutive SARS-CoV-2 positive patients admitted to one of five hospitals in British Columbia between December 19, 2021 and May 31,2022. We completed medical record reviews, and classified hospitalizations as being primarily for COVID-19 or with incidental SARS-CoV-2 infection. We applied the CDC algorithm and the Massachusetts classification to estimate the difference in hospital days, intensive care unit (ICU) days and in-hospital mortality and calculated sensitivity and specificity.

RESULTS

Of 42,505 Emergency Department patients, 1,651 were admitted and tested positive for SARS-CoV-2, with 858 (52.0%, 95% CI 49.6-54.4) admitted for COVID-19. Patients hospitalized for COVID-19 required ICU admission (14.0% versus 8.2%, p<0.001) and died (12.6% versus 6.4%, p<0.001) more frequently compared with patients with incidental SARS-CoV-2. Compared to case classification by clinicians, the CDC algorithm had a sensitivity of 82.9% (711/858, 95% CI 80.3%, 85.4%) and specificity of 98.1% (778/793, 95% CI 97.2%, 99.1%) for COVID-19-related admissions and underestimated COVID-19 attributable hospital days. The Massachusetts classification had a sensitivity of 60.5% (519/858, 95% CI 57.2%, 63.8%) and specificity of 78.6% (623/793, 95% CI 75.7%, 81.4%) for COVID-19-related admissions, underestimating total number of hospital and ICU bed days while overestimating COVID-19-related intubations, ICU admissions, and deaths.

CONCLUSION

Half of SARS-CoV-2 hospitalizations were for COVID-19 during the Omicron wave. The CDC algorithm was more specific and sensitive than the Massachusetts classification, but underestimated the burden of COVID-19 admissions.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT04702945.

Multimorbidity and Serological Response to SARS-CoV-2 Nine Months after 1st Vaccine Dose: European Cohort of Healthcare Workers-Orchestra Project

Understanding antibody persistence concerning multimorbidity is crucial for vaccination policies. Our goal is to assess the link between multimorbidity and serological response to SARS-CoV-2 nine months post-first vaccine. We analyzed Healthcare Workers (HCWs) from three cohorts from Italy, and one each from Germany, Romania, Slovakia, and Spain. Seven groups of chronic diseases were analyzed. We included 2941 HCWs (78.5% female, 73.4% ≥ 40 years old). Multimorbidity was present in 6.9% of HCWs. The prevalence of each chronic condition ranged between 1.9% (cancer) to 10.3% (allergies). Two regression models were fitted, one considering the chronic conditions groups and the other considering whether HCWs had diseases from ≥2 groups. Multimorbidity was present in 6.9% of HCWs, and higher 9-months post-vaccine anti-S levels were significantly associated with having received three doses of the vaccine (RR = 2.45, CI = 1.92-3.13) and with having a prior COVID-19 infection (RR = 2.30, CI = 2.15-2.46). Conversely, lower levels were associated with higher age (RR = 0.94, CI = 0.91-0.96), more time since the last vaccine dose (RR = 0.95, CI = 0.94-0.96), and multimorbidity (RR = 0.89, CI = 0.80-1.00). Hypertension is significantly associated with lower anti-S levels (RR = 0.87, CI = 0.80-0.95). The serological response to vaccines is more inadequate in individuals with multimorbidity.

Mortality in Catalonia during the summer of 2022 and its relation with high temperatures and COVID-19 cases

Purpose

To analyse the association between the mortality during the summer 2022 and either high temperatures or the COVID-19 wave with data from the Catalan Health Care System (7.8 million people).

Methods

We performed a retrospective study using publicly available data of meteorological variables, influenza-like illness (ILI) cases (including COVID-19) and deaths. The study comprises the summer months of the years 2021 and 2022. To compare the curves of mortality, ILI and temperature we calculated the z-score of each series. We assessed the observed lag between curves using the cross-correlation function. Finally, we calculated the correlation between the z-scores using the Pearson correlation coefficient (R²).

Results

During the study period, 33,967 deaths were reported in Catalonia (16,416 in the summer of 2021 and 17,551 in the summer of 2022). In 2022, the observed lag and the correlation between the z-scores of temperature and all-cause deaths was 3 days and R² = 0.86, while between ILI and all-cause deaths was 22 days and R² = 0.21. This high correlation between temperature and deaths increased up to 0.91 when we excluded those deaths reported as COVID-19 deaths, while the correlation between ILI and non-COVID-19 deaths decreased to -0.19. No correlation was observed between non-COVID deaths and temperature or ILI cases in 2021.

Conclusion

Our study suggests that the main cause of the increase in deaths during summer 2022 in Catalonia was the high temperatures and its duration. The contribution of the COVID-19 seems to be limited.

Elder and booster vaccination associates with decreased risk of serious clinical outcomes in comparison of Omicron and Delta variant: A meta-analysis of SARS-CoV-2 infection

BACKGROUND

The COVID-19 pandemic brings great pressure to the public health systems. This meta-analysis aimed to compare the clinical outcomes among different virus variants, to clarify their impact on medical resources and to provide evidence for the formulation of epidemic prevention policies.

METHODS

A systematic literature search was performed in the PubMed, Embase, and Cochrane Library databases using the key words "Omicron" and "Delta." The adjusted Risk ratios (RRs), Odds ratios (ORs) and Hazard ratios (HRs) were extracted, and RRs and Rate difference % (RD%) were used to interpret the risk estimates of the outcomes ultimately.

RESULTS

Forty-three studies were included, with 3,812,681 and 14,926,841 individuals infected with SARS-CoV-2 Delta and Omicron variant, respectively. The relative risks of hospitalization, death, ICU admission, and mechanical ventilation use after infection with the Omicron variant were all significantly reduced compared those after infection with the Delta variant (RRhospitalization = 0.45, 95%CI: 0.40-0.52; RRdeath = 0.37, 95%CI: 0.30-0.45; RRICU = 0.35, 95%CI: 0.29-0.42; RRmechanical ventilation = 0.33, 95%CI: 0.25-0.44). The change of both absolute and relative risks for hospitalization was more evident (RR = 0.47, 95%CI: 0.42-0.53；RD% =10.61, 95%CI: 8.64-12.59) and a significant increase was observed for the absolute differences in death in the elderly (RD% = 5.60, 95CI%: 4.65-6.55); the change of the absolute differences in the risk of hospitalization and death were most markedly observed in the patients with booster vaccination (RD%hospitalization = 8.60, 95CI%: 5.95-11.24; RD%death = 3.70, 95CI%: 0.34-7.06).

CONCLUSION

The ability of the Omicron variant to cause severe clinical events has decreased significantly, as compared with the Delta variant, but vulnerable populations still need to be vigilant. There was no interaction between the vaccination doses and different variants.

Pathophysiology of SARS-CoV-2 Infection of Nasal Respiratory and Olfactory Epithelia and Its Clinical Impact

PURPOSE OF REVIEW

While the predominant cause for morbidity and mortality with SARS-CoV-2 infection is the lower respiratory tract manifestations of the disease, the effects of SARS-CoV-2 infection on the sinonasal tract have also come to the forefront especially with the increased recognition of olfactory symptom. This review presents a comprehensive summary of the mechanisms of action of the SARS-CoV-2 virus, sinonasal pathophysiology of COVID-19, and the correlation with the clinical and epidemiological impact on olfactory dysfunction.

RECENT FINDINGS

ACE2 and TMPRSS2 receptors are key players in the mechanism of infection of SARS-CoV-2. They are present within both the nasal respiratory as well as olfactory epithelia. There are however differences in susceptibility between different groups of individuals, as well as between the different SARS-CoV-2 variants. The sinonasal cavity is an important route for SARS-CoV-2 infection. While the mechanism of infection of SARS-CoV-2 in nasal respiratory and olfactory epithelia is similar, there exist small but significant differences in the susceptibility of these epithelia and consequently clinical manifestations of the disease. Understanding the differences and nuances in sinonasal pathophysiology in COVID-19 would allow the clinician to predict and counsel patients suffering from COVID-19. Future research into molecular pathways and cytokine responses at different stages of infection and different variants of SARS-CoV-2 would evaluate the individual clinical phenotype, prognosis, and possibly response to vaccines and therapeutics.