Clinical Characteristics of COVID-19 Patients Infected by the Omicron Variant of SARS-CoV-2

Differences in chest imaging between Omicron and non-Omicron coronavirus disease 2019 (COVID-19) patients: a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) have posed a great threat to human health. We carried out this systematic review and meta-analysis for two objectives. First, to evaluate the differences in lung infection between the Omicron variants and the non-Omicron strains by chest computed tomography (CT); second, to evaluate the differences in chest CT features between COVID-19 patients with the Omicron variants and those with non-Omicron strains in CT-positive cases.

METHODS

We searched PubMed, Embase, Web of Science and China National Knowledge Infrastructure for articles and performed a meta-analysis using Stata 14.0 with a random effects model.

RESULTS

Our study included a total of 8126 patients with COVID-19, 4113 with the Omicron variants, and 4013 with non-Omicron strains. Patients with the Omicron variants were less likely to be CT-positive (OR = 0.14, 95% CI: 0.08-0.25), and further analysis among CT-positive patients was performed. Compared with the CT images of patients with non-Omicron strains, those of patients with the Omicron variants showed atypical pulmonary features (OR = 4.02, 95% CI: 2.31-6.98). Moreover, patients with the Omicron variants typically had lesions that were mainly located in the center of the lung (OR = 4.51, 95% CI: 1.38-14.76) and in a single lobe (OR = 1.72, 95% CI: 1.10-2.70). The patients with the Omicron variants were less likely to have lesions in both lungs (OR = 0.33, 95% CI: 0.15-0.69), more likely to have bronchial wall thickening (OR = 1.99, 95% CI: 1.05-3.77) and less likely to have the crazy-paving pattern (OR = 0.51, 95% CI: 0.33-0.81), linear opacity (OR = 0.26, 95% CI: 0.12-0.60), and vascular enlargement (OR = 0.54, 95% CI: 0.35-0.84).

CONCLUSIONS

Through meta-analysis, which yields the highest level of evidence for evidence-based medicine, we further confirmed that there were significant differences in the distribution and manifestations of lesions between patients with non-Omicron strains and those with the Omicron variants on chest CT. The variation in SARS-CoV-2 has never stopped. Our findings are useful for the diagnosis and treatment of new SARS-CoV-2 variants that may appear in the future and provide a basis for public health decision-making.

PROSPERO REGISTRATION NUMBER

CRD42024581869.

Exploring Tenebrio molitor as a source of low-molecular-weight antimicrobial peptides using a n in silico approach: correlation of molecular features and molecular docking

BACKGROUND

Yellow mealworm (Tenebrio molitor) larvae are increasingly recognized as a potential source of bioactive peptides due to their high protein content. Antimicrobial peptides from sustainable sources are a research topic of interest. This study aims to characterize the peptidome of T. molitor flour and an Alcalase-derived hydrolysate, and to explore the potential presence of antimicrobial peptides using in silico analyses, including prediction tools, molecular docking and parameter correlations.

RESULTS

T. molitor protein was hydrolysed using Alcalase, resulting in a hydrolysate (TMH10A) with a 10% degree of hydrolysis. The peptidome was analysed using LC-TIMS-MS/MS, yielding over 6000 sequences. These sequences were filtered using the PeptideRanker tool, selecting the top 100 sequences with scores >0.8. Bioactivity predictions indicated that specific peptides, particularly WLNSKGGF and GFIPYEPFLKKMMA, showed significant antimicrobial potential, particularly against bacteria, fungi and viruses. Correlations were found between antifungal activity and physicochemical properties such as net charge, hydrophobicity and isoelectric point.

CONCLUSIONS

The study identified specific T. molitor-derived peptides with strong predicted antimicrobial activity through in silico analysis. These peptides, particularly WLNSKGGF and GFIPYEPFLKKMMA, might offer potential applications in food safety and healthcare. Further experimental validation is required to confirm their efficacy. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Addressing Post-Acute COVID-19 Syndrome in Cancer Patients, from Visceral Obesity and Myosteatosis to Systemic Inflammation: Implications in Cardio-Onco-Metabolism

Cardiovascular disease and cancer are the two leading causes of morbidity and mortality in the world. The emerging field of cardio-oncology described several shared risk factors that predispose patients to both cardiovascular disease and cancer. Post-acute COVID-19 syndrome is a chronic condition that occurs in many patients who have experienced a SARS-CoV-2 infection, mainly based on chronic fatigue, sedentary lifestyle, cramps, breathing difficulties, and reduced lung performance. Post-acute COVID-19 exposes patients to increased visceral adiposity, insulin resistance, myosteatosis, and white adipose tissue content (surrounded by M1 macrophages and characterized by a Th1/Th17 phenotype), which increases the risk of cardiovascular mortality and cancer recurrence. In this review, the main metabolic affections of post-acute COVID-19 syndrome in cancer patients at low and high risk of cardiomyopathies will be summarized. Furthermore, several non-pharmacological strategies aimed at reducing atherosclerotic and cardiac risk will be provided, especially through anti-inflammatory nutrition with a low insulin and glycemic index, appropriate physical activity, and immune-modulating bioactivities able to reduce visceral obesity and myosteatosis, improving insulin-related signaling and myocardial metabolism.

A Comparative Analysis of Innate Immune Responses and the Structural Characterization of Spike from SARS-CoV-2 Gamma Variants and Subvariants

The SARS-CoV-2 P.1 variant, responsible for an outbreak in Manaus, Brazil, is distinguished by 12 amino acid differences in the S protein, potentially increasing its ACE-2 affinity and immune evasion capability. We investigated the innate immune response of this variant compared to the original B.1 strain, particularly concerning cytokine production. Blood samples from three severe COVID-19 patients were analyzed post-infection with both strains. Results showed no significant difference in cytokine production of mononuclear cells and neutrophils for either variant. While B.1 had higher cytopathogenicity, neither showed viral replication in mononuclear cells. Structural analyses of the S protein highlighted physicochemical variations, which might be linked to the differences in infectivity between the strains. Our studies point to the increased infectivity of P.1 could stem from altered immunogenicity and receptor-binding affinity.

Effect of the number of coronavirus disease 2019 (COVID-19) vaccination shots on the occurrence of pneumonia, severe pneumonia, and death in SARS-CoV-2-infected patients

Background

Coronavirus disease (COVID-19) has posed a significant threat to the lives and health of people worldwide since its onset in 2019. However, the relationship between the number of vaccination shots and the severity of SARS-CoV-2 infection in Chinese patients remains unclear.

Methods

We retrospectively collected information from 829 patients infected with SARS-CoV-2 in Ningbo Medical Center Lihuili Hospital from December 05, 2022 to March 31, 2023, then divided them into four groups based on the severity of pneumonia. Last, we compared the difference in the number of shots of COVID-19 vaccine between the four groups, considering potential confounding factors using univariate and multivariate logistic regression.

Results

Vaccination with two and three doses was positively associated with low prevalence of pneumonia and severe pneumonia both in crude and optimal models, while only three doses of the vaccine was correlated with low prevalence of death in SARS-CoV-2-infected patients. In optimal models, male SARS-CoV-2-infected individuals with advanced age were positively associated with high prevalence of pneumonia, severe pneumonia, and death; comorbidity with hypertension (OR = 2.532, p < 0.001) was positively associated with high prevalence of pneumonia (OR = 2.532, p < 0.001); and comorbidity with diabetes was positively associated with high prevalence of death (OR = 1.856, p = 0.011). However, this is a cross-sectional study and the causal relationships need to be further studied.

Conclusion

One dose of vaccine may not have a protective effect against pneumonia, severe pneumonia, and death; more than one dose of vaccine is an independent protective factor for pneumonia and severe pneumonia; and three doses of vaccine is an independent protective factor for death.

BF.7: a new Omicron subvariant characterized by rapid transmission

OBJECTIVES

BF.7 (BA.5.2.1.7) is a novel sublineage of Omicron BA.5, whose clinical characteristics are not yet established.

METHODS

From 28 September 2022 to 3 October 2022, the first 421 patients with BF.7 were assessed in Hohhot China and the clinical data were extracted and analysed. The basic reproduction number (R0) was estimated using a statistical model calculation method.

RESULTS

The R0 value was determined to be 13.79 (95% confidence interval: 12.44-15.24). The mean age was 33.43 ± 18.78 years. Asymptomatic, mild, moderate, severe, and critical patients accounted for 12.35% (52/421), 82.42% (347/421), 4.75% (20/421), 0.24% (1/421), and 0.24% (1/421) proportion, respectively. The main clinical symptoms were fever accounting for 41.09% (173/421), cough accounting for 41.09% (173/421), and throat dryness and soreness accounting for 30.88% (130/421). In the 3-dose vaccination subgroup, 31.22% (64) cases had a fever, which were significantly lower than 51.37% (96) cases of the 2-dose vaccination subgroup (p 0.000). The rates of abnormally increased C-reactive protein level in the 2-dose and 3-dose vaccination subgroups were 10.16% (19/187) and 4.88% (10/205), significantly lower than 66.67% (10/15) of the 1-dose vaccination subgroup (1-dose vs. 2-dose: p 0.000, 1-dose vs. 3-dose: p 0.000). Notably, the population with complete 3 doses of vaccination did not exhibit any severe or critical status.

DISCUSSION

BF.7 exhibited a higher transmission than previously emerged SARS-CoV-2. The vaccine against COVID-19 was found to relieve fever, nausea, and vomiting as well as reduce the abnormal ratio of lymphocytes, eosinophils, neutrophils, and the C-reactive protein level.

Clinical manifestations of pain in patients suffering from COVID-19 infected with Delta variant of SARS-Cov-2

Background

Although respiratory presentations of COVID-19 predominate, the extra pulmonary involvement such as muscle pain, joint pain, headache, back pain, abdominal pain, and sore throat are usually included in the clinical picture of the disease and it can be considered as an early symptom in COVID-19 patients. The objective of the present study was to determine the frequency, localization, and intensity of pain in COVID-19 patients hospitalized in Imam Khomeini hospital of Ardabil, Iran.

Methods and materials

A prospective study was conducted on 388 COVID-19 patients who were admitted to Ardabil, Iran's Imam Khomeini Central Hospital between March and June 2020. Demographic characteristics of patients and general clinical manifestations of pain at the first admission to the hospital, localization, severity, and continuity of pain were evaluated by using a questionnaire and the Visual Analog Scale (VAS).

Findings

For the 388 (51.3% female, age 47.25 + 15.55 and 48.7% male, age 50.12 + 15.26 years old) Delta COVID-19 patients, the median duration from illness onset to hospitalization was 5 days. Patients' complaints included 89.7% fatigue, 85.56% cough, 67.8% fever, 64.17% loss of taste, 63.91% loss of smell, 37.9% diarrhea, and 11.85% skin lesions, respectively. Pain including muscle, joint, bone and low back pain was the chief complaint in both sexes. Pain complaints had started on average 5 days before admission. The distribution of pain was 313 (80.41%) muscle pain, 264 (70.61%) joint pain, 299 (77.1%) headache, 208 (53.6%) low back pain, 312 (80.41%) sore throat, and 157 (40.46%) abdominal pain. Out of 388 patients, 292 (75.25%) had diffuse pain.

Conclusions

Acute pain including myalgia, sore throat, arthralgia, headache, and low back pain were the most common symptoms of COVID-19 patients. Viral diseases such as COVID-19 may trigger the immune system to release cytokines that lead to muscle pain. Patients presenting to healthcare centers with complaints of pain should be evaluated for suspected COVID-19 infection.

A Comparison of the Epidemiological Characteristics Between Influenza and COVID-19 Patients: A Retrospective, Observational Cohort Study

Background and objective It is crucial to make early differentiation between coronavirus disease 2019 (COVID-19) and seasonal influenza infections at the time of a patient's presentation to the emergency department (ED). In light of this, this study aimed to identify key epidemiological, initial laboratory, and radiological differences that would enable early recognition during co-circulation. Methods This was a retrospective, observational cohort study. All adult patients presenting to our ED at the Watford General Hospital, UK, with a laboratory-confirmed diagnosis of COVID-19 (2019/20) or influenza (2018/19) infection were included in this study. Demographic, laboratory, and radiological data were collected. Binary logistic regression was employed to determine features associated with COVID-19 infection rather than influenza. Results Chest radiographs suggestive of viral pneumonitis and older age (≥80 years) were associated with increased odds of having COVID-19 [odds ratio (OR): 47.00, 95% confidence interval (CI): 21.63-102.13 and OR: 64.85, 95% CI: 19.96-210.69 respectively]. Low eosinophils (<0.02 x 109/L) were found to increase the odds of COVID-19 (OR: 2.12, 95% CI: 1.44-3.10, p<0.001). Conclusions Gaining awareness about the epidemiological, biological, and radiologic presentation of influenza-like illness can be useful for clinicians in ED to differentiate between COVID-19 and influenza. This study showed that older age, eosinopenia, and radiographic evidence of viral pneumonitis significantly increase the odds of having COVID-19 compared to influenza. Further research is needed to determine if these findings are affected by acquired or natural immunity.

Differential platelet activation through an interaction with spike proteins of different SARS-CoV-2 variants

COVID-19 disease is associated with an increased risk of thrombotic complications, which contribute to high short-term mortality. Patients with COVID-19 demonstrate enhanced platelet turnover and reactivity, which may have a role in the development of thrombotic events and disease severity. Evidence has suggested direct interaction between SARS-CoV-2 and platelets, resulting in platelets activation. Here, we compare the effect of various SARS-CoV-2 spike variants on platelet activation. Engineered lentiviral particles were pseudotyped with spike SARS-CoV-2 variants and incubated with Platelet Rich Plasma obtained from healthy individuals. The pseudotyped SARS-CoV-2 exhibiting the wild-type Wuhan-Hu spike protein stimulated platelets to increase expression of the surface CD62P and activated αIIbβ3 markers by 3.5 ± 1.2 and 3.3 ± 0.7 fold, respectively (P = 0.004 and 0.003). The Delta variant induced much higher levels of platelet activation; CD62P expression was increased by 6.6 ± 2.2 fold and activated αIIbβ3 expression was increased by 5.0 ± 1.5 fold (P = 0.005 and 0.026, respectively). The Omicron BA.1 and the Alpha variants induced the lowest level of activation; CD62P expression was increased by 1.7 ± 0.4 and 1.6 ± 0.9 fold, respectively (P = 0.003 and 0.008), and activated αIIbβ3 expression by 1.8 ± 1.1 and 1.6 ± 0.8, respectively (P = 0.003 and 0.001). The Omicron BA.2 variant induced an increase of platelets activation comparable to the Wuhan-Hu (2.8 ± 1.2 and 2.1 ± 1.3 fold for CD62P and activated αIIbβ3 markers, respectively). The results obtained for various COVID-19 variants are in correlation with the clinical severity and mortality reported for these variants.

SARS-CoV-2 Omicron variant infection affects blood platelets, a comparative analysis with Delta variant

Introduction

In November 2021, the SARS-CoV-2 Omicron variant of concern has emerged and is currently dominating the COVID-19 pandemic over the world. Omicron displays a number of mutations, particularly in the spike protein, leading to specific characteristics including a higher potential for transmission. Although Omicron has caused a significant number of deaths worldwide, it generally induces less severe clinical signs compared to earlier variants. As its impact on blood platelets remains unknown, we investigated platelet behavior in severe patients infected with Omicron in comparison to Delta.

Methods

Clinical and biological characteristics of severe COVID-19 patients infected with the Omicron (n=9) or Delta (n=11) variants were analyzed. Using complementary methods such as flow cytometry, confocal imaging and electron microscopy, we examined platelet activation, responsiveness and phenotype, presence of virus in platelets and induction of selective autophagy. We also explored the direct effect of spike proteins from the Omicron or Delta variants on healthy platelet signaling.

Results

Severe Omicron variant infection resulted in platelet activation and partial desensitization, presence of the virus in platelets and selective autophagy response. The intraplatelet processing of Omicron viral cargo was different from Delta as evidenced by the distribution of spike protein-positive structures near the plasma membrane and the colocalization of spike and Rab7. Moreover, spike proteins from the Omicron or Delta variants alone activated signaling pathways in healthy platelets including phosphorylation of AKT, p38MAPK, LIMK and SPL76 with different kinetics.

Discussion

Although SARS-CoV-2 Omicron has different biological characteristics compared to prior variants, it leads to platelet activation and desensitization as previously observed with the Delta variant. Omicron is also found in platelets from severe patients where it induces selective autophagy, but the mechanisms of intraplatelet processing of Omicron cargo, as part of the innate response, differs from Delta, suggesting that mutations on spike protein modify virus to platelet interactions.

[COVID-19: Neurological manifestations and complications during the acute phase of the disease]

The neurological manifestations and complications of the acute phase of COVID-19 are numerous. They mainly concern the central nervous system in the frequent forms of encephalopathy, encephalitis and neurovascular pathologies. Peripheral neurological manifestations mainly include acute polyneuropathies such as Guillain-Barré syndrome and intensive care neuromyopathies. Most of these manifestations were described during the first wave of the pandemic. The epidemiological, clinical, paraclinical, pathophysiological and therapeutic aspects are addressed in this general review of the literature published from 2020 to early 2023.

Risk Factors and Disease Profile Associated with the Nucleic Acid Conversion Time of COVID-19 Patients Infected with the SARS-CoV-2 Omicron Variant in Fangcang Shelter Hospitals

Purpose

This study aimed to determine the clinical profile connected to the nucleic acid conversion time of COVID-19 patients harboring the SARS-CoV-2 Omicron variant at the hospitals at the Fangcang shelter.

Methods

We reported 39,584 COVID-19 patients who were hospitalized in Shanghai, China, between April 5 and May 5, 2022, and who had contracted the Omicron strain of SARS-CoV-2. Demographic data, medical and vaccination history, clinical symptoms, and NCT were reported for the patient.

Results

The median age of the patients with COVID-19 included in this study was 45 (interquartile range [IQR]: 33-54), and 64.2% of them were male. The two most prevalent comorbidities among the patients were hypertension and diabetes. Additionally, we discovered that the percentage of unimmunized patients was negligible (13.2%). We found that male sex, age under 60, and other comorbidities including hypertension and diabetes are significant risk factors for extending NCT when we analyzed the risk variables for NCT. We discovered that vaccination with two or more doses can significantly reduce NCT. The analysis of the young (18-59 years) and older (60 years) populations produced the same outcomes.

Conclusion

Our findings confirm that a full COVID-19 vaccine series or booster doses are highly recommended to significantly reduce NCT. In order to reduce NCT, it is also advised that elderly people who have no clear contraindications take vaccination shots.

Multidimensional analysis of immune cells from COVID-19 patients identified cell subsets associated with the severity at hospital admission

BACKGROUND

SARS-CoV-2 emerged as a new coronavirus causing COVID-19, and it has been responsible for more than 760 million cases and 6.8 million deaths worldwide until March 2023. Although infected individuals could be asymptomatic, other patients presented heterogeneity and a wide range of symptoms. Therefore, identifying those infected individuals and being able to classify them according to their expected severity could help target health efforts more effectively.

METHODOLOGY/PRINCIPAL FINDINGS

Therefore, we wanted to develop a machine learning model to predict those who will develop severe disease at the moment of hospital admission. We recruited 75 individuals and analysed innate and adaptive immune system subsets by flow cytometry. Also, we collected clinical and biochemical information. The objective of the study was to leverage machine learning techniques to identify clinical features associated with disease severity progression. Additionally, the study sought to elucidate the specific cellular subsets involved in the disease following the onset of symptoms. Among the several machine learning models tested, we found that the Elastic Net model was the better to predict the severity score according to a modified WHO classification. This model was able to predict the severity score of 72 out of 75 individuals. Besides, all the machine learning models revealed that CD38+ Treg and CD16+ CD56neg HLA-DR+ NK cells were highly correlated with the severity.

CONCLUSIONS/SIGNIFICANCE

The Elastic Net model could stratify the uninfected individuals and the COVID-19 patients from asymptomatic to severe COVID-19 patients. On the other hand, these cellular subsets presented here could help to understand better the induction and progression of the symptoms in COVID-19 individuals.

Flattening the Curve after the Initial Outbreak of Coronavirus Disease 2019: A Data-Driven Modeling Analysis for the Omicron Pandemic in China

China is relaxing COVID-19 measures from the "dynamic zero tolerance" (DZT) level. The "flatten-the-curve" (FTC) strategy, which decreases and maintains the low rate of infection to avoid overwhelming the healthcare system by adopting relaxed nonpharmaceutical interventions (NPIs) after the outbreak, has been perceived as the most appropriate and effective method in preventing the spread of the Omicron variant. Hence, we established an improved data-driven model of Omicron transmission based on the age-structured stochastic compartmental susceptible-latent-infectious-removed-susceptible model constructed by Cai to deduce the overall prevention effect throughout China. At the current level of immunity without the application of any NPIs, more than 1.27 billion (including asymptomatic individuals) were infected within 90 days. Moreover, the Omicron outbreak would result in 1.49 million deaths within 180 days. The application of FTC could decrease the number of deaths by 36.91% within 360 days. The strict implementation of FTC policy combined with completed vaccination and drug use, which only resulted in 0.19 million deaths in an age-stratified model, will help end the pandemic within about 240 days. The pandemic would be successfully controlled within a shorter period of time without a high fatality rate; therefore, the FTC policy could be strictly implemented through enhancement of immunity and drug use.

Plasma metabolomic characterization of SARS-CoV-2 Omicron infection

Omicron variants of SARS-CoV-2 have spread rapidly worldwide; however, most infected patients have mild or no symptoms. This study aimed to understand the host response to Omicron infections by performing metabolomic profiling of plasma. We observed that Omicron infections triggered an inflammatory response and innate immune, and adaptive immunity was suppressed, including reduced T-cell response and immunoglobulin antibody production. Similar to the original SARS-CoV-2 strain circulating in 2019, the host developed an anti-inflammatory response and accelerated energy metabolism in response to Omicron infection. However, differential regulation of macrophage polarization and reduced neutrophil function has been observed in Omicron infections. Interferon-induced antiviral immunity was not as strong in Omicron infections as in the original SARS-CoV-2 infections. The host response to Omicron infections increased antioxidant capacity and liver detoxification more than in the original strain. Hence, these findings suggest that Omicron infections cause weaker inflammatory alterations and immune responses than the original SARS-CoV-2 strain.

Clinical Characteristics of SARS-CoV-2 Omicron Cases in Pune, Maharashtra, India

Background The SARS-CoV-2 Omicron variant, within two months of its detection, replaced the Delta variant to become the dominant circulating variant globally. Therefore, it is essential to understand the characteristics of the disease caused by the variant and its impact on vaccination. Methods A total of 165 confirmed Omicron cases attending a tertiary care hospital in Pune, Maharashtra, between December 2021 to February 2022 were studied. Their demographic, clinical, and immunization history was recorded. Results Among the 165 cases, 7.88% were B.1.1.529 Omicron cases, 25.45% were BA.1 Omicron cases, and 66.67% were BA.2 Omicron cases. Of these 165 patients, 146 (88.48%) were discharged after treatment, 12 (7.27%) died during hospitalization, and seven (4.24%) were brought dead. The presence of one or more comorbid conditions was seen in 15.15%, of which diabetes mellitus and hypertension (28% each) were the most common conditions. Older age (greater than 60 years), an important risk factor for poor outcomes, was present in 9.1% of cases. Among the 165 cases, vaccination with at least one dose of vaccine was found in 80.61% of cases. Out of 165 cases, clinical data was available for 158 cases. Of these 158 cases, 86.71% had symptoms, and 13.29% were asymptomatic. Fever, followed by cough, myalgia, runny nose, and headache, were the most common presenting symptoms. The mean duration of illness was 2.69 days, with 91.14% of cases having the illness for less than five days, and 89.24% of cases had a National Early Warning Score (NEWS) of 1-4, suggesting a good prognosis. In 93.90% of cases, the chest X-ray findings were normal. Of the 158 cases, 92.41% of cases recovered with supportive treatment, and only 7.59% of cases required oxygen therapy. Conclusion The current study shows that the Omicron variant caused mild disease with reduced need for hospital admission and oxygen therapy in India.

Increased SARS-CoV-2 seroprevalence and spread of infection without awareness among healthcare workers through 2020-2022 in a Japanese medical center

Despite Japan's high vaccination coverage, daily numbers of new COVID-19 cases have been high. However, studies on the seroprevalence among Japanese people and the causative factors for rapid spread have remained limited. In this study, we aimed to examine the seroprevalence and associated factors in healthcare workers (HCWs) of a medical center in Tokyo using blood samples drawn at annual check-ups from 2020 to 2022. We found that of the 3,788 HCWs in 2022 (by mid-June), 669 were seropositive for N-specific antibodies (tested by Roche Elecsys Anti-SARS-CoV-2 assay); the seroprevalence surged from 0.3% in 2020 and 1.6% in 2021 to 17.7% in 2022. Notably, our study found 325 (48.6%; 325/669) cases were infected without awareness. Among those with a previously PCR-confirmed SARS-CoV-2 infection during the past three years, 79.0% (282/357) were found after January 2022, after the Omicron variant was first detected in Tokyo at the end of 2021. This study indicates the fast spread of the SARS-CoV-2 among HCWs during the Omicron surge in Japan. The high percentage of infection without awareness may be a key driving factor causing rapid person-to-person transmission, as shown in this medical center with high vaccination coverage and strict infection control measures.

Predictive factors for severe placental damage in pregnant women with SARS-CoV-2 infection

INTRODUCTION

SARS-Cov-2 infection during pregnancy can lead to severe placental lesions characterized by massive perivillous fibrin deposition, histiocytic intervillositis and trophoblast necrosis. Diffuse placental damage of this kind is rare, but can sometimes lead to obstetric complications, such as intrauterine fetal death (IUFD). The objectives of this study were to identify possible predictors of severe placental lesions.

METHODS

We retrospectively studied 96 placentas from SARS-Cov-2 positive pregnant women who gave birth between March 2020 and March 2022. Cases with and without severe placental lesions were compared in terms of clinical and laboratory findings.

RESULTS

Twelve of the 96 patients had severe placental lesions. There was no significant association with diabetes, obesity or severe clinical maternal disease. In contrast, presence of severe placental lesions was significantly associated with neonatal intensive care, cesarean section, prematurity, IUFD, intrauterine growth restriction (IUGR), gestational age, maternal hypofibrinogenemia and thrombocytopenia. No cases of severe placental lesions were observed in vaccinated patients or in those with the Omicron variant.

DISCUSSION

In these patients, severe placental lesions due to SARS-Cov-2 were significantly associated with the presence of coagulation abnormalities (hypofibrinogenemia and thrombocytopenia), IUGR and gestational age. These results support laboratory and ultrasound monitoring of these parameters in pregnant women with SARS-Cov-2 infection, especially during the second trimester, to predict potential negative fetal outcomes.

Prolonged SARS-CoV-2 Infection and Intra-Patient Viral Evolution in an Immunodeficient Child

BACKGROUND

With the progression of the Coronavirus disease pandemic, the number of mutations in the viral genome has increased, showing the adaptive evolution of severe acute respiratory syndrome coronavirus 2 in humans and intensification in transmissibility. Long-term infections also allow the development of viral diversity. In this study, we report the case of a child with severe combined immu presenting a prolonged severe acute respiratory syndrome coronavirus 2 infection. We aimed to analyze 3 naso-oropharyngeal swab samples collected between August and December 2021 to describe the amino acid changes present in the sequence reads that may have a role in the emergence of new viral variants.

METHODS

The whole genome from clinical samples was sequenced through high throughput sequencing and analyzed using a workflow to map reads and then find variations/single-nucleotide polymorphisms. In addition, the samples were isolated in cell culture, and a plaque forming units assay was performed, which indicates the presence of viable viral particles.

RESULTS

The results obtained showed that the virus present in all samples is infectious. Also, there were 20 common mutations among the 3 sequence reads, found in the ORF1ab and ORF10 proteins. As well, a considerable number of uncommon mutations were found.

CONCLUSIONS

In conclusion, we emphasize that genomic surveillance can be a useful tool to assess possible evolution signals in long-term patients.

Factors associated with prolonged viral shedding in older patients infected with Omicron BA.2.2

Background

This study explores the risk factors associated with viral shedding time in elderly Chinese patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron.

Methods

Participants infected with SARS-CoV-2 omicron were enrolled in a retrospective study, and divided into two groups according to shedding time (≥10 days, "late clearance group" and <10 days, "early clearance group").

Results

A total of 180 patients were enrolled in the study (88 early, 92 late), with a median viral shedding time of 10 days and a mean age of 77.02 years. Prolonged SARS-CoV-2 omicron shedding was associated with old age (p = 0.007), lack of vaccination (p = 0.001), delayed admission to hospital after onset of diagnosis (p = 0.001), D-dimer (p = 0.003), and methylprednisolone treatment (p = 0.048). In multivariate analysis, vaccination (OR, 0.319, 95% CI, 0.130-0.786, p = 0.013), Paxlovid (OR, 0.259, 95% CI, 0.104-0.643, p = 0.004), and time from onset of diagnosis to admission (OR, 1.802, 95% CI, 1.391-2.355, p = 0.000) were significantly associated with viral clearance.

Conclusions

Time from onset of diagnosis to hospitalization, lack of treatment with Paxlovid, and lack of vaccination were independent risk factors in elderly Chinese patients infected with SARS-CoV-2 omicron for prolonged viral shedding.

A Detailed Overview of SARS-CoV-2 Omicron: Its Sub-Variants, Mutations and Pathophysiology, Clinical Characteristics, Immunological Landscape, Immune Escape, and Therapies

The COVID-19 pandemic has created significant concern for everyone. Recent data from many worldwide reports suggest that most infections are caused by the Omicron variant and its sub-lineages, dominating all the previously emerged variants. The numerous mutations in Omicron's viral genome and its sub-lineages attribute it a larger amount of viral fitness, owing to the alteration of the transmission and pathophysiology of the virus. With a rapid change to the viral structure, Omicron and its sub-variants, namely BA.1, BA.2, BA.3, BA.4, and BA.5, dominate the community with an ability to escape the neutralization efficiency induced by prior vaccination or infections. Similarly, several recombinant sub-variants of Omicron, namely XBB, XBD, and XBF, etc., have emerged, which a better understanding. This review mainly entails the changes to Omicron and its sub-lineages due to it having a higher number of mutations. The binding affinity, cellular entry, disease severity, infection rates, and most importantly, the immune evading potential of them are discussed in this review. A comparative analysis of the Delta variant and the other dominating variants that evolved before Omicron gives the readers an in-depth understanding of the landscape of Omicron's transmission and infection. Furthermore, this review discusses the range of neutralization abilities possessed by several approved antiviral therapeutic molecules and neutralizing antibodies which are functional against Omicron and its sub-variants. The rapid evolution of the sub-variants is causing infections, but the broader aspect of their transmission and neutralization has not been explored. Thus, the scientific community should adopt an elucidative approach to obtain a clear idea about the recently emerged sub-variants, including the recombinant variants, so that effective neutralization with vaccines and drugs can be achieved. This, in turn, will lead to a drop in the number of cases and, finally, an end to the pandemic.

Clinical characteristics of 1139 mild cases of the SARS-CoV-2 Omicron variant infected patients in Shanghai

In March 2022, the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surged during the Coronavirus Disease 2019 (COVID-19) pandemic in Shanghai, but over 90% of patients were mild. This study included 1139 COVID-19 patients mildly infected with the Omicron variant of SARS-CoV-2 in Shanghai from May 1 to 10, 2022, aiming to clarify the demographic characteristics and clinical symptoms of patients with mild Omicron infection. The clinical phenotypes of Omicron infection were identified by model-based cluster analysis to explore the features of different clusters. The median age of the patients was 41.0 years [IQR: 31.0-52.0 years] and 73.0% were male. The top three clinical manifestations are cough (57.5%), expectoration (48.3%), and nasal congestion and runny nose (43.4%). The prevalence of nasal congestion and runny nose varied significantly across the doses of vaccinations, with 23.1% in the unvaccinated population and 30%, 45.9%, and 44.3% in the 1-dose, 2-dose and 3-dose vaccinated populations, respectively. In addition, there were significant differences for fever (23.1%, 26.0%, 28.6%, 18.4%), head and body heaviness (15.4%, 14.0%, 26.7%, 22.4%), and loss of appetite (25.6%, 30.0%, 33.6%, 27.7%). The unvaccinated population had a lower incidence of symptoms than the vaccinated population. Cluster analysis revealed that all four clusters had multisystemic symptoms and were dominated by both general and respiratory symptoms. The more severe the degree of the symptoms was, the higher the prevalence of multisystemic symptoms will be. The Omicron variant produced a lower incidence of symptoms in mildly infected patients than previous SARS-CoV-2 variants, but the clinical symptoms caused by the Omicron variant are more complex, so that it needs to be differentiated from influenza.

Hematological characteristics of COVID-19 patients with fever infected by the Omicron variant in Shanghai: A retrospective cohort study in China

BACKGROUND

A wave of the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has rapidly spread in Shanghai, China. Hematological abnormalities have been reported in coronavirus disease 2019 (COVID-19) patients; however, the difference in hematological parameters between COVID-19 patients with fever and patients who are febrile from other causes remains unexplored.

METHODS

This retrospective cohort study enrolled 663 SARS-CoV-2 positive patients identified by RT-PCR. Clinical parameters, including age, sex, and threshold cycle values of all COVID-19 patients, and hematological parameters of COVID-19 patients in the fever clinic were abstracted for analysis.

RESULTS

Overall, 60.8% of COVID-19 patients were male, and the median age was 45 years. Most of COVID-19 patients were asymptomatic, while 25.8% of patients showed fever and 10.9% of patients had other emergencies. COVID-19 patients with fever had significantly lower white blood cells (WBCs), neutrophils, lymphocytes, platelets and C-reactive protein (CRP), and significantly higher monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), mean platelet volume (MPV), and mean platelet volume-to-platelet ratio (MPR) levels, compared with those in SARS-CoV-2 negative patients with fever from other causes (p < 0.05). Neutrophil-to-lymphocyte ratio (NLR), PLR, and systemic inflammatory index (SII) levels were significantly higher in COVID-19 patients with emergencies (p < 0.05). WBCs showed the best performance with an area under the curve (0.756), followed by neutrophils (0.730) and lymphocytes (0.694) in the diagnosis of COVID-19 in the fever clinic.

CONCLUSION

WBCs, neutrophils, lymphocytes, platelets, CRP and MLR, PLR, and MPR may be useful in early diagnosis of COVID-19 in the fever clinic.

[Short-term persistent symptoms in preschool children with mild/common coronavirus disease 2019 caused by Omicron variant infection after discharge: a follow-up study]

OBJECTIVES

To investigate the persistent symptoms in preschool children after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection, and to provide a basis for developing follow-up plans after infection and reducing and preventing related symptoms after infection.

METHODS

The children, aged 0-5 years, who had Omicron BA.2 infection and were discharged from the pediatric ward of Shanghai Renji Hospital South Branch from April 13 to May 8, 2022, were enrolled as subjects, and related demographic and clinical data were collected. The children were followed up from the time to SARS-CoV-2 clearance for two consecutive tests with an interval of >24 hours till 4-5 weeks after clearance, and telephone follow-up was performed on the primary caregivers to investigate related persistent symptoms.

RESULTS

Among the 103 children who met the inclusion criteria, there were 61 boys and 42 girls, with a median age of 18 months. The primary caregivers who had received two or more doses of COVID-19 vaccine accounted for 64.1% (66/103). Fever (98.1%, 101/103) was the most common symptom in these children, followed by cough/expectoration (63.1%, 65/103), gastrointestinal problems (37.9%, 39/103), loss of appetite (30.1%, 31/103), weakness (27.2%, 28/103), and nasal obstruction/runny nose (16.5%, 17/103). The follow-up at 1 month after discharge reported that 44 children (42.7%) had at least one persistent symptom, including respiratory symptoms in 14 children (13.6%) and gastrointestinal problems in 19 children (18.4%). The children whose primary caregivers received two or more doses of COVID-19 vaccine had a significantly shorter time to SARS-CoV-2 clearance than those whose primary caregivers did not receive or only received one dose of COVID-19 vaccine (P<0.05), while there was no significant difference between the two groups in the proportion of children with at least one persistent symptom (P>0.05).

CONCLUSIONS

Nearly half of the preschool children may have related persistent symptoms after SARS-CoV-2 Omicron variant infection, mainly gastrointestinal and respiratory symptoms. Most of the symptoms may be mild, and continuous follow-up is needed to observe their outcomes. Vaccination of COVID-19 vaccine for primary caregivers has a certain protective effect on children.

Effect of Hypertension Comorbidity on Clinical Characteristics of COVID-19 Patients Infected by the Wild-Type, the Delta or Omicron Variant SARS-CoV-2

Background

Hypertension was the most common comorbidity in patients with the coronavirus disease 2019 (COVID-19). We aim to study the effect of comorbid hypertension on the clinical characteristics of COVID-19 patients with the underlying mechanism.

Methods

We retrospectively analyzed 459, 336 and 659 COVID-19 patients who were infected by the wild-type, the delta and omicron variant, respectively, including their demographic information, medical history, immunization record (if available), and laboratory parameters, to investigate the clinical differences between COVID-19 patients with and without hypertension.

Results

In this study 26.1%, 26.8%, and 12.9% of COVID-19 patients had pre-existing hypertension in the cohort of wild-type, delta, and omicron variant, respectively. Compared to non-hypertensive peers, hypertension patients demonstrated older age, higher occurrence of other major comorbidities, and poorer blood or coagulation parameters, showing worse prognosis. In case of the delta or omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hypertension patients produced robust antibody responses, although indistinguishable whether it was due to vaccination or natural infection and resembled those of non-hypertensive peers in blood cell and coagulation profiles with still varying viremic damages to major organs.

Conclusions

Resultantly, COVID-19 infection promoted pro-inflammatory and pro-thrombotic states in hypertension patients, whereas vaccinated individuals would exhibit favorable prognoses.

Comparison of Clinical Presentation and Vaccine Effectiveness Among Omicron and Non-omicron SARS Coronavirus-2 Patients

Introduction The rapidly mutating Omicron SARS-CoV-2 variant has replaced the previous dominant SARS-CoV-2 variants like alpha, and delta resulting in the amplification of coronavirus disease 2019 (COVID-19) cases. The present study was conducted to compare the clinical profile and vaccination status in patients infected with Omicron and non-Omicron SARS-CoV-2 variants. Methods All patients who tested positive for coronavirus disease 2019 (COVID-19) during the study period (January 2022 to February 2022) were further tested for detection of SARS-CoV-2 Omicron variant by using Omisure kit (TATA MD CHECK RT-PCR, TATA MEDICAL AND DIAGNOSTICS LIMITED, Tamil Nadu, INDIA). Clinico-demographic factors and vaccination status were compared between both Omicron and non-Omicron groups. Results A total of 1,722 patients who tested positive for COVID-19 were included in the study, of which 656 (38.1%) were Omicron and 1,066 (61.9%) were non-Omicron SARS-CoV-2 variants. Blood group and vaccination status were the major predictors for Omicron. The proportion of male patients was 58.4% in the Omicron group and 57.9% in the non-Omicron group. Maximum cases (86.2%) belonged to >18-60 years age group, 7.3% to >60 years age group, and least to 0-18 years (6.5%). The average age of the study participants was 35.4 ± 14.5 years. Vaccinated participants had less chance of having Omicron than the unvaccinated participants (p-value - 0.003). Fever and loss of smell were found to be significantly associated with the non-Omicron SARS-CoV-2 variant. (p-value < 0.05). Conclusion The present study reflects that the clinical course of the disease is milder in Omicron as compared to the non-Omicron variant. However rapid rise in cases can badly affect the healthcare system demanding good preparedness to tackle all the predicaments. Good Vaccination coverage should be of utmost priority irrespective of the variant type.

What Is New in Prophylaxis and Treatment of COVID-19 in Renal Transplant Patients? A Report from an ESOT Meeting on the Topic

I should highlight that this manuscript is not a formal review on the topic, but a report from an ESOT meeting held on 22 June 2022. The assumption of immunosuppressants exposes kidney transplant recipients to the risk of infections, including COVID-19 infection. A transplant patient having COVID-19 infection raises several questions, including whether the immunosuppressive therapy should be reduced with the consequent risk of favoring acute rejections. Patient vaccination before transplantation is probably the gold standard to avoid the risk of COVID-19 infection after transplantation. In the case of transplant patients, three measures may be undertaken: vaccination, use of monoclonal antibodies and use of therapeutic antiviral small molecules. Concerning vaccination, it is still debated which one is the best and how many doses should be administered, particularly considering the new variants of the virus. The onset of virus variants has stimulated researchers to find new active vaccines. In addition, not all transplant patients develop antibodies. An alternative prophylactic measure to be principally used for patients that do not develop antibodies after vaccination is the use of monoclonal antibodies. These drugs may be administered as prophylaxis or in the early stage of the disease. Finally, the small antiviral molecules may be used again as prophylaxis or treatment. Their major drawbacks are their interference with immunosuppressive drugs and the fact that some of them cannot be administered to patients with low eGFR.

Epidemiological characteristics of Omicron and Delta SARS-CoV-2 variant infection in Santiago, Chile

The variant of concern (VOC) SARS-CoV-2 Omicron (B.1.1529) has been described as a highly contagious variant but less virulent than the current variant being monitored (VBM) Delta (B.1.617.2), causing fewer cases of hospitalizations, symptomatology, and deaths associated with COVID-19 disease. Although the epidemiological comparison of both variants has been previously reported in other countries, no report indicates their behavior and severity of infection in Chile. In this work, we report for the first time the effect of the Omicron and Delta variants in a cohort of 588 patients from the Hospital de Urgencia Asistencia pública (HUAP), a high-complexity health center in Santiago, Chile. This report is framed at the beginning of Chile's third wave of the COVID-19 pandemic, with a marked increase in the Omicron variant and a decrease in the circulating Delta variant. Our results indicated a similar proportion of patients with a complete vaccination schedule for both variants. However, the Delta variant was associated with a higher prevalence of hospitalization and more significant symptomatology associated with respiratory distress. On the other hand, our data suggest that vaccination is less effective in preventing infection by the Omicron variant. This antecedent, with a low severity but high contagiousness, suggests that the Omicron variant could even collapse the primary health care service due to the high demand for health care.

Comparison of clinical characteristics between SARS-CoV-2 Omicron variant and Delta variant infections in China

BACKGROUND

The continued 'evolution' of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the emergence of the Omicron variant after the Delta variant, resulting in a significant increase in the number of people with COVID-19. This increase in the number of cases continues to have a significant impact on lives. Therefore, a more detailed understanding of the clinical characteristics of Omicron infection is essential.

METHODS

Using medical charts, we extracted clinical information for 384 patients infected with the Omicron variant in Anyang City, Henan Province, China. Epidemiology and clinical characteristics were compared with a cohort of people infected with the Delta variant in Zhengzhou in 2021.

FINDINGS

Common initial symptoms at onset of illness were cough [240 (63%)], expectoration [112 (29%)], fever [96 (25%)], nasal congestion [96 (25%)] and myalgia or fatigue [30 (6%)]. In patients with the Omicron variant, levels of total cholesterol, low-density lipoprotein and creatinine increased in 52 (14%), 36 (9%) and 58 (15%) patients, respectively, compared with patients with the Delta variant [one (1%), one (1%) and two (2%)]. Levels of triglyceride and high-density lipoprotein also increased. In patients with the Omicron variant, the levels of specific gravity and the erythrocyte sedimentation rate were increased in 115 (30%) and 81 (21%) patients, and serum levels of complement 3 decreased in 93 (41%).

RESULTS

Compared with patients infected with Delta, no major differences in initial clinical symptoms were identified in patients infected with Omicron. However, dyslipidemia and kidney injury were much more severe in patients with the Omicron variant, and the erythrocyte sedimentation rate was increased. Due to decreased levels of complement 3, the immunity of patients with the Omicron variant was weak.

The Rescue of the Romanian Health System by the Emergency Departments during the Fourth Wave of COVID-19 Pandemic

The COVID-19 pandemic has led to the confrontation of the health system with the need to identify solutions for providing medical care to a very large number of patients. The main objective of our study was to describe the measures taken to provide optimal medical care to patients who presented themselves in one of the large emergency hospitals of Romania in the fourth wave of the COVID-19 pandemic. Material and Methods: We conducted a retrospective, observational study on a group of 1417 patients. The statistical analysis was performed using R. Results: The average length of stay of patients in the emergency departments was approximately 2.6 h, increasing to up to 15 days in some more severe cases. For rapid antigen tests, the highest positivity rate for SARS-CoV-2 was identified in patients aged >75 years (53%). Among the identified risk factors associated with the need for mechanical ventilation were advanced age (α < 0.001) and lack of vaccination against SARS-CoV-2 (α < 0.001). Discussion and conclusions: A method of saving the Romanian health system in full hospital bed occupancy conditions in the wards proved to be the provision of medical care in emergency departments.

Impact of COVID-19 Vaccination on Healthcare Worker Infection Rate and Outcome during SARS-CoV-2 Omicron Variant Outbreak in Hong Kong

Immune escape is observed with SARS-CoV-2 Omicron (Pango lineage B.1.1.529), the predominant circulating strain worldwide. A booster dose was shown to restore immunity against Omicron infection; however, real-world data comparing mRNA (BNT162b2; Comirnaty) and inactivated vaccines’ (CoronaVac; Sinovac) homologous and heterologous boosting are lacking. A retrospective study was performed to compare the rate and outcome of COVID-19 in healthcare workers (HCWs) with various vaccination regimes during a territory-wide Omicron BA.2.2 outbreak in Hong Kong. During the study period from 1 February to 31 March 2022, 3167 HCWs were recruited, and 871 HCWs reported 746 and 183 episodes of significant household and non-household close contact. A total of 737 HCWs acquired COVID-19, all cases of which were all clinically mild. Time-dependent Cox regression showed that, compared with two-dose vaccination, three-dose vaccination reduced infection risk by 31.7% and 89.3% in household contact and non-household close contact, respectively. Using two-dose BNT162b2 as reference, two-dose CoronaVac recipient had significantly higher risk of being infected (HR 1.69 p < 0.0001). Three-dose BNT162b2 (HR 0.4778 p< 0.0001) and two-dose CoronaVac + BNT162b2 booster (HR 0.4862 p = 0.0157) were associated with a lower risk of infection. Three-dose CoronaVac and two-dose BNT162b2 + CoronaVac booster were not significantly different from two-dose BNT162b2. The mean time to achieve negative RT-PCR or E gene cycle threshold 31 or above was not affected by age, number of vaccine doses taken, vaccine type, and timing of the last dose. In summary, we have demonstrated a lower risk of breakthrough SARS-CoV-2 infection in HCWs given BNT162b2 as a booster after two doses of BNT162b2 or CoronaVac.

Clinical characteristics of the severe acute respiratory syndrome coronavirus 2 omicron variant compared with the delta variant: a retrospective case-control study of 318 outpatients from a single sight institute in Japan

Background

Clinical characteristics, including laboratory parameters, of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant have been limited.

Methods

This retrospective case-control study was conducted in a single hospital. Patients with coronavirus disease 2019 (COVID-19) who visited the Asahikawa City Hospital outpatient department as new patients and underwent blood tests were included in this study. We analyzed the data from January 2022 to April 2022 during the Omicron phase and from April 2021 to October 2021 during the Delta phase. Patients who were treated at other hospitals after visiting our hospital were excluded. All blood tests were performed before treatment for COVID-19 was initiated. Demographic information, laboratory data, and clinical courses were extracted from electronic medical records. We matched the two groups by age and comorbidities and compared their characteristics. We also analyzed factors associated with pneumonia in the Omicron phase.

Results

A total of 151 Omicron patients and 167 delta patients were analyzed in this study. The mean age, rate of comorbidities, and vaccination were significantly higher in the Omicron group. The number of patients with pneumonia or those requiring oxygen, admissions, or both was significantly lower in the Omicron group. Lactate dehydrogenase (LDH), C-reactive protein (CRP), ferritin, aspartate aminotransferase (AST), and neutrophil-to-lymphocyte ratio (NLR) levels were significantly lower in the Omicron group. Compared with the mild symptom and pneumonia groups in the Omicron group, older age, higher body mass index (BMI), higher non-vaccination, higher LDH, and higher CRP levels were associated with the pneumonia group.

Conclusion

The Omicron variant is associated with a reduction in hospitalization and the risk of pneumonia compared to the delta variant in a real-life clinical setting. In the Omicron variant, the risk of pneumonia is related to high-risk factors, laboratory data such as LDH and CRP levels, and no vaccination.

SARS-CoV-2 Antibody Response against Mild-to-Moderate Breakthrough COVID-19 in Home Isolation Setting in Thailand

Background: In December 2021, Omicron replaced Delta as the dominant coronavirus disease 2019 (COVID-19) variant in Thailand. Both variants embody diverse epidemiological trends and immunogenicity. We investigated whether Delta and Omicron patients’ biological and clinical characteristics and immunogenicity differed post-COVID-19 infection. Methods: This retrospective cohort study investigated the clinical outcomes and laboratory data of 5181 patients with mild-to-moderate COVID-19 (Delta, 2704; Omicron, 2477) under home isolation. We evaluated anti-receptor-binding domain immunoglobulin G (anti-RBD IgG) and surrogate viral neutralizing (sVNT) activity in 495 individuals post-COVID-19 infection during the Delta pandemic. Results: Approximately 84% of all patients received favipiravir. The median cycle threshold (Ct) values were lower for Omicron patients than Delta patients (19 vs. 21; p < 0.001), regardless of vaccination status. Upper respiratory tract symptoms were more frequent with Omicron patients than Delta patients. There were no significant associations between Ct and Omicron symptoms (95% confidence interval 0.98−1.02). A two-dose vaccine regimen reduced hospital readmission by 10% to 30% and death by under 1%. Anti-RBD IgG and sVNT against Delta were higher among older individuals post-COVID-19 infection. Older individuals expressed anti-RBD IgG and sVNT for a more extended period after two-dose vaccination than other age groups. Conclusions: After a full vaccination course, breakthrough mild-to-moderate Delta and Omicron infections have limited immunogenicity. Prior infections exert reduced protection against later reinfection or infection from novel variants. However, this protection may be sufficient to prevent hospitalization and death, particularly in countries where vaccine supplies are limited.

Case Report: The Experience of Managing a Moderate ARDS Caused by SARS-CoV-2 Omicron BA.2 Variant in Chongqing, China: Can We Do Better?

Background

The severe coronavirus disease 2019 (COVID-19) pandemic is still raging worldwide, and the Omicron BA.2 variant has become the new circulating epidemic strain. However, our understanding of the Omicron BA.2 variant is still scarce. This report aims to present a case of a moderate acute respiratory distress syndrome (ARDS) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron BA.2 variant and to discuss some management strategies that may benefit this type of case.

Case Presentation

A 78-year-old man, who had four negative nucleic acid tests and a fifth positive, was admitted to our hospital. This patient was generally good upon admission and tested negative for anti-SARS-CoV-2 antibodies even after receiving two doses of the COVID-19 vaccine. On the 7th day of hospitalization, he developed a moderate ARDS. Improved inflammatory index and decreased oxygen index were primarily found in this patient, and a series of treatments, including anti-inflammation and oxygen therapies, were used. Then this patient's condition improved soon and reached two negative results of nucleic acid tests on the 18th day of hospitalization.

Conclusion

At-home COVID-19 rapid antigen test could be complementary to existing detection methods, and the third booster dose of COVID-19 vaccine may be advocated in the face of the omicron BA.2 variant. Anti-inflammatory and oxygen therapies are still essential treatments for ARDS patients infected with SARS-CoV-2 Omicron BA.2 variant.