Regret, Delete, (Do Not) Repeat: An Analysis of Self-Cleaning Practices on Twitter After the Outbreak of the COVID-19 Pandemic (preprint)

During the outbreak of the COVID-19 pandemic, many people shared their symptoms across Online Social Networks (OSNs) like Twitter, hoping for others' advice or moral support. Prior studies have shown that those who disclose health-related information across OSNs often tend to regret it and delete their publications afterwards. Hence, deleted posts containing sensitive data can be seen as manifestations of online regrets. In this work, we present an analysis of deleted content on Twitter during the outbreak of the COVID-19 pandemic. For this, we collected more than 3.67 million tweets describing COVID-19 symptoms (e.g., fever, cough, and fatigue) posted between January and April 2020. We observed that around 24% of the tweets containing personal pronouns were deleted either by their authors or by the platform after one year. As a practical application of the resulting dataset, we explored its suitability for the automatic classification of regrettable content on Twitter.

Retrospective screening of anti-SARS-CoV-2 antibodies in cerebrospinal fluid samples of patients with neurological manifestations of unknown etiology in a tertiary care hospital during the pandemic period (preprint)

Since the onset of the pandemic, neurological manifestations of COVID-19 are increasingly being reported in the scientific literature. However, since these manifestations are not the primary symptoms, SARS-CoV-2 is not being considered the etiological agent in most cases. The primary objective of this study was to screen for anti-SARS-CoV-2 antibodies in cerebrospinal fluid (CSF) of patients with neurological manifestations of undiscerned etiology and correlate the antibody levels with the clinical characteristics, derangement in blood & CSF biochemical parameters, comorbidities, radiological findings and prognosis. CSF samples of clinically suspected encephalitis cases of unknown etiology, during the pandemic period (January 2021 to April 2022) were included in the study. Patients were categorised into two groups based on the presence or absence of anti-SARS-CoV-2 antibodies (IgG and IgM) in the CSF. Statistical analysis was done using IBM SPSS Statistics (Version 20.0) software. Out of 112 samples tested, 89 samples had IgG antibodies and three samples had both IgM and IgG antibodies against SARS-CoV-2 virus. Viral nucleic acid could not be detected in any of the tested CSF samples. Altered sensorium and fever were found to be the most significant clinical symptoms associated with the presence of anti-SARS-CoV-2 antibodies in the CSF. An increase in CSF biochemical parameters like glucose, protein, white blood cells along with blood biochemical parameters like serum albumin, alanine transaminase and C - reactive protein was seen in patients who had anti-SARS-CoV-2 antibodies in the CSF. Statistically, no significant correlation was found between the presence of anti-SARS-CoV-2 IgG antibodies and the clinical and biochemical parameters in both groups of patients.

Virological evidence of the impact of non-pharmaceutical interventions against COVID-19 in a resource-limited setting (preprint)

Ecuador was an early COVID-19 hotspot with substantial COVID-19-mortality. In developed countries, low socioeconomic status is associated with COVID-19 infection and low compliance with non-pharmaceutical interventions (NPIs). However, if NPI were successful in resource-limited settings with high human mobility and informal labour is still unclear. We performed a retrospective observational molecular and serological study of Ecuadors reference laboratory. We tested 1,950 respiratory samples from COVID-19 surveillance for SARS-CoV-2 and 12 respiratory viruses using RT-PCR, characterized 642 SARS-CoV-2 genomes, and examined SARS-CoV-2 seroprevalence in 1,967 samples from patients with fever in Ecuadors reference laboratory during 2020-2021. Molecular and serological data were compared to NPI stringency in Bayesian, maximum-likelihood and modelling frameworks. SARS-CoV-2 (Pearson correlation test; r=-0.74; p=0.01) and other respiratory viruses (r=-0.68; p=0.02) detection correlated negatively with NPI stringency. SARS-CoV-2 seroprevalence increased from <1% during February-March 2020 to 50% within 6 weeks and plateaued after NPI implementation. Decrease of effective reproduction number <1 and antibody reactivity over time suggested intense SARS-CoV-2 transmission during pandemic onset, subsequently limited by NPIs. Phylogeographic analyses revealed that travel restrictions were implemented late not preventing 100 near-parallel SARS-CoV-2 introductions, and implementation of NPIs modified SARS-CoV-2 geographic spread by restricting recreational activity. NPIs stringency correlated negatively with the number of circulating SARS-CoV-2 lineages (r=-0.69; p=0.02). Virological evidence supports NPIs restricting human movement as an effective public health tool to control the spread of respiratory pathogens in resource-limited settings, providing a template for emerging SARS-CoV-2 variants and future epidemics.

COVID-19 or seasonal influenza? How to distinguish in people younger than 65 years old: A retrospective observational cohort study comparing the 2009 pandemic influenza A H1N1 with 2022 SARS-CoV-2 Omicron BA.2 outbreaks in China. (preprint)

Objective: This study attempted to explore the difference of clinical characteristics in H1N1 influenza infection and SARS-CoV-2 Omicron infection in people younger than 65 years old, in order to better identify the two diseases. Methods: A total of 127 H1N1 influenza patients diagnosed from May 2009 to July 2009 and 3265 patients diagnosed and identified as SARS-CoV-2 Omicron BA.2 variant from March 2022 to May 2022 were admitted in this study. Through the 1 : 2 match based on age (The difference is less than 2 years), gender and underlying diseases115 patients with H1N1 infection and 230 patients with SARS-CoV-2 Omicron BA.2 infection (referred to as H1N1 group and Omicron group) were included in the statistics. The clinical manifestations of H1N1 group were compared with those of Omicron group. Logistic regression was performed to analyze the possible independent risk factors of H1N1 group and Omicron group. And multiple linear regression was used to analyze the factors for time for nucleic acid negativization (NAN) . Results: The median age of the two groups was 21 [11,26] years. Compared with the H1N1 group, the Omicron group had lower white blood cell count and CRP levels, less fever, nasal congestion, sore throat, cough, sputum and headache, while more olfactory loss, muscle soreness and LDH abnormalities. The Omicron group used less antibiotics and antiviral drugs, and the NAN time was longer (17 [ 14,20] VS 4 [ 3,5], P < 0.001). After logistic regression, it was found that fever, cough, headache, and increased white blood cell count were more correlated with the H1N1 group, while muscle soreness and LDH abnormalities were more correlated with the Omicron group. After analyzing the factors of NAN time, it was found that fever (B 1.529, 95 % CI [0.149,2.909], P = 0.030) significantly predicted longer NAN time in Omicron patients. Conclusion: This study comprehensively evaluated the similarities and differences in clinical characteristics between SARS-CoV-2 Omicron infection and 2009 H1N1 influenza infection, which is of great significance for a better understanding for these diseases.

Infrared image method for possible COVID-19 detection through febrile and subfebrile people screening.

This study proposed an infrared image-based method for febrile and subfebrile people screening to comply with the society need for alternative, quick response, and effective methods for COVID-19 contagious people screening. The methodology consisted of: (i) Developing a method based on facial infrared imaging for possible COVID-19 early detection in people with and without fever (subfebrile state); (ii) Using 1206 emergency room (ER) patients to develop an algorithm for general application of the method, and (iii) Testing the method and algorithm effectiveness in 2558 cases (RT-qPCR tested for COVID-19) from 227,261 workers evaluations in five different countries. Artificial intelligence was used through a convolutional neural network (CNN) to develop the algorithm that took facial infrared images as input and classified the tested individuals in three groups: fever (high risk), subfebrile (medium risk), and no fever (low risk). The results showed that suspicious and confirmed COVID-19 (+) cases characterized by temperatures below the 37.5 °C fever threshold were identified. Also, average forehead and eye temperatures greater than 37.5 °C were not enough to detect fever similarly to the proposed CNN algorithm. Most RT-qPCR confirmed COVID-19 (+) cases found in the 2558 cases sample (17 cases/89.5%) belonged to the CNN selected subfebrile group. The COVID-19 (+) main risk factor was to be in the subfebrile group, in comparison to age, diabetes, high blood pressure, smoking and others. In sum, the proposed method was shown to be a potentially important new tool for COVID-19 (+) people screening for air travel and public places in general.

Safety of SARS-CoV2 vaccination and COVID-19 short-term outcome in pediatric acquired demyelinating disorders of central nervous system: A single center experience.

Introduction: Concern of a correlation between disease relapse in patients with acquired demyelinating disorders of central nervous system (CNS) and SARS-CoV2 vaccines has been raised. In this single center study, we retrospectively evaluated safety of SARS-CoV2 vaccination and COVID-19 short-term outcome in pediatric acquired demyelinating disorders of CNS. Materials and methods: Patients with multiple sclerosis (MS), myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) and neuromyelitis optica spectrum disorder (NMOSD) with disease onset before 18 years of age were included. Demographic and clinical data, and information regarding previous SARS-CoV-2 infection and vaccination were collected. Results: We included nine patients with MOGAD. Six patients received SARS-CoV2 vaccination and complained pain at injection site while only one had fever and fatigue. Median follow-up was 28 weeks (range 20-48). Seven patients had COVID-19 occurring with mild flu-like symptoms and median follow-up was 28 weeks (range 24-34). Nobody had disease relapse. Five patients with NMOSD were included. All patients received SARS-CoV2 vaccination (BNT162b2-Pfizer-BioNTech). The median follow-up was 20 weeks (range 14-24) and only two patients complained pain at injection site, fever and fatigue. Three patients had also COVID-19 with mild flu-like symptoms, despite two of them being under immunosuppressive treatment. Lastly, forty-three patients with MS were included. 35 out of 43 received SARS-CoV2 vaccination with a median follow-up of 24 weeks (range 8-36). Fourteen patients had no side effects, while 21 complained mild side effects (mainly pain at injection site) and one experienced a disease relapse with complete recovery after steroid therapy. At vaccination, all but one were under treatment. Sixteen patients had COVID-19 occurring with mild symptoms. Discussion: COVID-19 outcome was good although many patients were under immunosuppressive treatment. Vaccine-related side effects were frequent but were mild and self-limited. Only one MS patient had a post-vaccination relapse with complete recovery after steroid therapy. In conclusion, our data support the safety of SARS-CoV-2 vaccines in pediatric MS, MOGAD and NMOSD.

Epidemiological Predictors of Positive SARS-CoV-2 Polymerase Chain Reaction Test in Three Cohorts: Hospitalized Patients, Healthcare Workers, and Military Population, Serbia, 2020.

(1) Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its resulting coronavirus disease 2019 (COVID-19) has caused a fast-moving pandemic. Diagnostic testing, aimed to identify patients infected with SARS-CoV-2, plays a key role in controlling the COVID-19 pandemic in different populations. (2) Methods: This retrospective cohort study aimed to investigate predictors associated with positive polymerase chain reaction (PCR) SARS-CoV-2 test results in hospitalized patients, healthcare workers (HCWs), and military personnel (MP) during 2020, before the widespread availability of COVID-19 vaccines. Persons with a positive test result were compared with persons with a negative test result in three cohorts during the study period. (3) Results: A total of 6912 respondents were tested, and 1334 (19.3%) of them had positive PCR SARS-CoV-2 test results. Contact with a known COVID-19 case within 14 days (p < 0.001; OR: 1.48; 95% CI: 1.25-1.76), fever (p < 0.001; OR: 3.66; 95% CI: 3.04-4.41), cough (p < 0.001; OR: 1.91; 95% CI: 1.59-2.30), headache (p = 0.028; OR: 1.24; 95% CI: 1.02-1.50), and myalgia/arthralgia (p < 0.001; OR: 1.99; 95% CI: 1.65-2.42) were independently associated with positive PCR SARS-CoV-2 test results in the cohort of MP. Furthermore, fever (p < 0.001; OR: 2.75; 95% CI: 1.83-4.13), cough (p < 0.001; OR: 2.04; 95% CI: 1.32-3.13), headache (p = 0.008; OR: 1.76; 95% CI: 1.15-2.68), and myalgia/arthralgia (p = 0.039; OR: 1.58; 95% CI: 1.02-2.45) were independently associated with positive PCR SARS-CoV-2 test results in the cohort of HCWs. Moreover, independent predictors of positive PCR SARS-CoV-2 test results in hospitalized patients were contact with a known COVID-19 case within 14 days (p < 0.001; OR: 2.56; 95% CI: 1.71-3.83), fever (p < 0.001; OR: 1.89; 95% CI: 1.38-2.59), pneumonia (p = 0.041; OR: 1.45; 95% CI: 1.01-2.09), and neurological diseases (p = 0.009; OR: 0.375; 95% CI: 0.18-0.78). (4) Conclusions: According to data gathered from cohorts of hospitalized patients, HCWs, and MP, before the widespread availability of COVID-19 vaccines in Serbia, we can conclude that predictors of positive PCR SARS-CoV-2 test results in MP and HCWs were similar. Accurate estimates of COVID-19 in different population groups are important for health authorities.

Understanding the Effect of Magnetic Field and Nanoparticle Concentration on Brownian Relaxation Time in Magnetic Nanofluids: A Semi-Analytical Model (preprint)

Magnetic nanofluids are used in many types of applications. Therefore, the dynamics of magnetic nanoparticle systems under the action of magnetic field were intensively studied, lately. Many studies related to biomedical applications consider the Brownian relaxation time independent from the magnetic field and nanoparticle concentration. This modelling assumption can lead to certain errors in the estimation of some parameters of interest. Thus, these errors also propagate in the determination of the effective relaxation time, which is of great importance in the estimation of some quantities of interest such as SAR (Specific Absorption Rate) or ILP (Intrinsic Loss Power Values) for magnetic hyperthermia. This paper presents a study of these errors starting from a semi-analytical model. Our experimental results can be useful to understand the mechanisms of magnetic relaxation of a nanofluid in various conditions and, above all, to create suitable numerical evaluation models.

The first case of acute necrotizing encephalopathy associated with coronavirus disease in a child in Asia: a case report and literature review (preprint)

Background Acute necrotic encephalopathy（ANE） in children is a very rare complication of Severe Acute Respiratory Syndrome Coronavirus 2（SARS-CoV-2） infection, which has rarely been reported worldwide. Case presentation A 45-day-old girl was admitted to our hospital with fever and listlessness. A nose swab tested positive for novel coronavirus nucleic acid, and her cerebrospinal fluid was positive for SARS-CoV-2. An early head magnetic resonance imaging (MRI) scan indicated multiple abnormal signals in her bilateral cerebral hemispheres, and encephalitis was diagnosed. Twenty-three days after hospitalization, bilateral cerebral atrophy-like changes were observed by MRI, with multiple softening lesions in the bilateral cerebral hemispheres, accompanied by convulsions. She was admitted to hospital for mechanically-assisted ventilation, and her condition improved after treatment of her symptoms, including anti-epileptic medication, anti-infection drugs, glucocorticoids, and immunoglobulins. Conclusions Acute necrotic encephalopathy associated with novel coronavirus infection in children should be detected and treated as early as possible. Satisfactory short-term efficacy can be obtained, but long-term neurological sequelae often linger.

The Impact of Omicron Wave on Pediatric Febrile Seizure.

BACKGROUND: The coronavirus disease 2019 (COVID-19) omicron (B.1.1.529) variant reduced the risk of severe disease compared with the original strain and other variants, but it appeared to be highly infectious, which resulted in an exponential increase in confirmed cases in South Korea. As the number of confirmed cases increased, so did the number of pediatric patients' hospitalization. This study aims to evaluate the frequency and clinical features of febrile seizure associated with the COVID-19 omicron variant in children. METHODS: We retrospectively reviewed the medical records of children aged under 18 years with febrile seizure who were tested for COVID-19 from February 2020 to April 2022 at Ajou University Hospital, South Korea. Based on the dominant variants, we divided the period into the pre-omicron (from February 2020 to December 2021) and omicron periods (from January 2022 to April 2022) and compared the clinical characteristics between the two. Also, we compared the clinical characteristics of febrile seizure between COVID-19 positive and negative group during the omicron period. RESULTS: Among the 308 children, 211 patients (9.2 patients/months) and 97 patients (24.3 patients/months) were grouped into pre-omicron and omicron periods, respectively. Compared with the pre-omicron period, patients in the omicron period showed significantly higher mean age (pre-omicron vs. omicron, 22.0 vs. 28.0 months; P = 0.004) and COVID-19 positive results (pre-omicron vs. omicron, 0.5% vs. 62.9%; P < 0.001). As the COVID-19 confirmed cases in the omicron period increased, the number of COVID-19 associated febrile seizure also increased. In the omicron period, 61 children were confirmed to be positive for COVID-19, and COVID-19 positive group showed statistically significant higher mean age (positive vs. negative, 33.0 vs. 23.0 months; P = 0.003) and peak body temperature than the negative group (positive vs. negative, 39.1°C vs. 38.6°C; P = 0.030). Despite the lack of significance, COVID-19 positive group showed longer seizure time, multiple seizure episodes, and higher prevalence of complex febrile seizure. CONCLUSION: The frequency of COVID-19 associated febrile seizure increased in the omicron periods. In addition, in this period, children with febrile seizure diagnosed with COVID-19 had a higher mean age and higher peak body temperature.

SARS-COV-2 Infection in Children in Emergency Departments in Spain: A Multicenter Study.

OBJECTIVES: The first cases of infection by SARS-CoV-2 in the Spanish pediatric population were reported on early March 2020. Although most were mild or asymptomatic, new forms of clinical presentation and severity were reported with the evolution of the pandemic. We aimed to describe demographics, clinical features, and management of children with COVID-19 treated in Spanish emergency departments (EDs). METHODS: A multicenter registry including 15 pediatric EDs was carried out. Patients younger than 18 years with confirmed acute SARS-CoV2 infection diagnosed between March and August 2020 were included. RESULTS: Three hundred ninety-five patients were analyzed (median age, 4.3 years). Fifty-five (13.9%) had comorbidities, and 141 (35.7%) a household contact with confirmed COVID-19. The most reported symptoms were fever (85.2%) and cough (41.7%). Fifty (12.5%) were asymptomatic. Seventeen (4.9%) were not well-appearing at presentation. Children underwent a blood test in 26.7% and a chest X-ray in 21.4%; findings were often unremarkable. Symptomatic treatment was prescribed to 80%; 6 (1.7%) received antiviral treatment. Seventy-one (20.6%) were hospitalized, and 3 (0.9%) were admitted to the intensive care unit; no patient died. The main clinical diagnoses were fever without a source (38%) and upper respiratory tract infection (32.2%); 4 (1.1%) presented a multisystem inflammatory syndrome. CONCLUSIONS: Most pediatric COVID-19 cases in EDs during the first months of the pandemic were healthy, well-appearing children, presenting with fever +/- respiratory symptoms. In a significant number of cases, there was household transmission. Most children were managed as outpatients with symptomatic treatment, being exceptional the evolution to a serious illness.

Human exposure risk assessment for infectious diseases due to temperature and air pollution: an overview of reviews (preprint)

Air pollution and global temperature change are expected to affect infectious diseases. Yet to date overview of systematic reviews assessing the exposure risk of air pollutants and temperature on infectious diseases is unavailable. PubMed, Embase, the Cochrane Library, Web of Science, and the Cumulative Index to Nursing and Allied Health Literature were searched. Systematic reviews and meta-analyses investigated the exposure risk of pollutants or temperature on infectious diseases were included. Two investigators screened literature, extracted data and performed the risk of bias assessments independently. A total of 23 articles met the inclusion criteria, which 3 (13%) were "low" quality and 20 (87%) were "critically low" quality. COVID-19 morbidity was associated with long-term exposure PM2.5 (RR = 1.056 per 1μg/m  3, 95% CI: 1.039-1.072) and NO2 (RR = 1.042 per 1 μg/m 3, 95% CI: 1.017-1.068). In addition, for each 1°C increase in temperature, the risk of dengue fever morbidity increased 13% (RR = 1.130 per 1°C, 95% CI: 1.120-1.150), infectious diarrhea morbidity increased 8% (RR =1.080 per 1°C, 95% CI: 1.050-1.200), and hand, foot and mouth disease (HFMD) morbidity increased 5% (RR = 1.050 per 1 °C, 95% CI: 1.020-1.080). In conclusion, PM2.5 and NO2 increased the risk of COVID-19 and temperatures were associated with dengue, infectious diarrhoea and HFMD morbidity. Moreover, the exposure risk of temperature on COVID-19 need to be further explored. 

Associations of COVID-19 Symptoms with Omicron Subvariants BA.2 and BA.5, Host Status, and Clinical Outcomes: A Registry-Based Observational Study in Sapporo, Japan (preprint)

Background: Previous SARS-CoV-2 infection and vaccination, coupled to rapid evolution of SARS-CoV-2 variants, have modified COVID-19 clinical manifestations. We characterized clinical symptoms of COVID-19 individuals in omicron BA.2 and BA.5 Japanese pandemic periods to identify omicron and subvariant associations between symptoms, immune status, and clinical outcomes. Methods: Individuals registered in Sapporo's web-based COVID-19 information system entered 12 pre-selected symptoms, days since symptom onset, vaccination history, SARS-CoV-2 infection history, and background. Symptom frequencies, variables associated with symptoms, and symptoms associated with progression to severe disease were analysed. Results: For all omicron-infected individuals, cough was the most common symptom (62.7%), followed by sore throat (60.7%), nasal discharge (44.3%), and fever (38.8%). Omicron BA.5 infection was associated with a higher symptom burden than BA.2 in vaccinated and unvaccinated individuals. Omicron breakthrough-infected individuals with 3 or more vaccinations or previous infection were less likely to exhibit systemic symptoms, but more likely to exhibit upper respiratory symptoms. Infected elderly individuals had lower odds for all symptoms, but, when symptoms were manifest, systemic symptoms were associated with an increased risk, whereas upper respiratory symptoms with a decreased risk, of severe disease. Conclusion: Host immunological status, omicron subvariant, and age were associated with a spectrum of COVID-19 symptoms and outcomes. BA.5 produced a greater symptom burden than BA.2. Vaccination and prior infection mitigated systemic symptoms and improved outcomes, but increased upper respiratory tract symptom burden. Systemic, but not upper respiratory, symptoms in the elderly heralded severe disease.

Physical side effects of covid-19 vaccines reported among healthcare workers in Sudan: A cross-sectional study (preprint)

Background: COVID-19 is quickly becoming a global health issue. For the first time in the history of extremely contagious illnesses, a vaccine has been created in one year. Vaccination is having a beneficial impact across the globe. Elimination of this sickness is still far from the reality due to virus mutations. Methods: A descriptive, cross-sectional study was conducted to investigate the side effects of the COVID-19 vaccine among healthcare workers in Kosti Teaching Hospital, Sudan (October 2021- June 2022). Google forms were used to collect data. Samples were taken using total coverage. The data were analyzed using SPSS v28 and the association between variables was checked using the Q-square and Fisher's Exact Test. Result: This study includes (133) participants, the majority are female (77.4%) and the rest were male (22.6%) and the main age group is (37.98 ± 9.5 SD) years. About three-quarters of the study population )76.7%) showed side effects after getting a vaccine. The following adverse effects were experienced by study participants: mild pain at the injection site (77.5%), fever (65%), headache (50%) and fatigue (43%). About 7% were unable to work the next day owing to side effects. Significant differences were observed between the side effects and marital status; p-value = (.005), type of vaccine p-value = (.042) and age p-value = (.021). No significant differences between vaccine side effects and age, previous infection with COVID-19, gender, occupation, number of hours spent at work and infection with other chronic illnesses (p-value<  0.05).  Conclusion: Based on current research, pain at the injection site is the most frequent adverse reaction, demonstrating the vaccine's safety and the absence of any problems or lethal effects. Additionally, these side effects don't significantly affect daily activities.

The Impact of Omicron Wave on Pediatric Febrile Seizure.

BACKGROUND: The coronavirus disease 2019 (COVID-19) omicron (B.1.1.529) variant reduced the risk of severe disease compared with the original strain and other variants, but it appeared to be highly infectious, which resulted in an exponential increase in confirmed cases in South Korea. As the number of confirmed cases increased, so did the number of pediatric patients' hospitalization. This study aims to evaluate the frequency and clinical features of febrile seizure associated with the COVID-19 omicron variant in children. METHODS: We retrospectively reviewed the medical records of children aged under 18 years with febrile seizure who were tested for COVID-19 from February 2020 to April 2022 at Ajou University Hospital, South Korea. Based on the dominant variants, we divided the period into the pre-omicron (from February 2020 to December 2021) and omicron periods (from January 2022 to April 2022) and compared the clinical characteristics between the two. Also, we compared the clinical characteristics of febrile seizure between COVID-19 positive and negative group during the omicron period. RESULTS: Among the 308 children, 211 patients (9.2 patients/months) and 97 patients (24.3 patients/months) were grouped into pre-omicron and omicron periods, respectively. Compared with the pre-omicron period, patients in the omicron period showed significantly higher mean age (pre-omicron vs. omicron, 22.0 vs. 28.0 months; P = 0.004) and COVID-19 positive results (pre-omicron vs. omicron, 0.5% vs. 62.9%; P < 0.001). As the COVID-19 confirmed cases in the omicron period increased, the number of COVID-19 associated febrile seizure also increased. In the omicron period, 61 children were confirmed to be positive for COVID-19, and COVID-19 positive group showed statistically significant higher mean age (positive vs. negative, 33.0 vs. 23.0 months; P = 0.003) and peak body temperature than the negative group (positive vs. negative, 39.1°C vs. 38.6°C; P = 0.030). Despite the lack of significance, COVID-19 positive group showed longer seizure time, multiple seizure episodes, and higher prevalence of complex febrile seizure. CONCLUSION: The frequency of COVID-19 associated febrile seizure increased in the omicron periods. In addition, in this period, children with febrile seizure diagnosed with COVID-19 had a higher mean age and higher peak body temperature.

Tender cervical lymphadenitis as a herald of multi-system inflammatory syndrome in COVID-19 infection of children and adolescents: a report of two cases.

BACKGROUND: Post-COVID-19 multisystem inflammatory syndrome (MIS) has been increasingly recognized but fever with isolated tender cervical lymphadenitis as the initial presentation has been rarely reported. We present 2 female patients one a child and the other an adolescent. CASE PRESENTATION: Case 1 was a 13-year-old girl who presented with tender cervical lymphadenopathy and fever 3-weeks post-COVID-19, and then developed features of MIS 5 days later. Case 2, also female, was 18 years old. She had no history of COVID-19 infection or immunization but had a serologic diagnosis of COVID-19. She similarly presented with fever and tender cervical lymphadenopathy, and then progressed rapidly to develop features of MIS. Both patients responded well to treatment with immunosuppressants and intravenous immunoglobulin. CONCLUSION: Tender cervical lymphadenopathy could be the herald of multi-system inflammatory syndrome following COVID-19 infection among children and adolescents, which the clinicians must have a good suspicion about.

Differential clinical characteristics and performance of home antigen tests between parents and children after household transmission of SARS-CoV-2 during the Omicron variant pandemic.

OBJECTIVES: The SARS-CoV-2 Omicron variant pandemic struck Taiwan in April 2022. Rapid antigen tests (RATs) play an important role in providing rapid results during a pandemic. However, self-collected samples by the children's caregivers without the supervision of medical personnel raise some concerns. METHODS: This study was performed to investigate household transmission, clinical characteristics, and antigen performance in a special COVID-19 family clinic in a children's hospital. The performance of at-home RATs was evaluated based on reverse transcription-polymerase chain reaction. RESULTS: We included 627 patients in our study between May 11 and June 10, 2022. The COVID-19 full vaccination rate was significantly higher in adults (98.5%) than in children (5.9%, P <0.001). The transmission rate was significantly higher in children (91.3%) than in adults (76.6%, P <0.001). Infected children had more incidents of fever (82.4% vs 22.4%, P <0.001) and a higher peak fever than adults. Based on the reverse transcription-polymerase chain reaction, the negative predictive rate of the home RAT was only 38.7% (95% confidence interval: 31.9-46.0%) in children. The cycle threshold value of those with false-negative antigen tests was significantly lower in children. CONCLUSION: Children had a higher transmission rate, more fever, and higher peak fever than adults. Home RAT has a suboptimal negative predictive rate in children.

Weekly symptom profiles of nonhospitalized individuals infected with SARS-CoV-2 during the Omicron outbreak in Hong Kong: A retrospective observational study from a telemedicine center.

Omicron BA.2.2 is the dominant variant in the Hong Kong outbreak since December 31, 2021. There is no study reporting the weekly symptom profile after infection. In this retrospective study, participants who tested positive for SARS-CoV-2 after December 31, 2021, and registered in the telemedicine system between March 14 and May 6, 2022, were analyzed. Among registered 12 950 self-quarantined COVID-19-positive patients, 11 776 symptomatic patients were included for weekly symptom profile analysis. A total of 4718 (40.1%) patients reported symptoms in the first week after a positive test, 2501 (21.2%) in the second week, 1498 (12.7%) in the third week, 1048 (8.9%) in the fourth week, and 2011 (17.1%) in over 4 weeks. Cough was the most common symptom in all participants. Patients in the first week had higher odds of reporting fever (0.206, 95% confidence interval [CI]: 0.161-0.263, p < 0.001) and sore throat (0.228, 95% CI: 0.208-0.252, p < 0.001). Patients in over 4 weeks had higher odds of reporting fatigue (1.263, 95% CI: 1.139-1.402, p < 0.001). Further, having at least two vaccine doses linked to lower odds of having fever (0.675, 95% CI: 0.562-0.811, p < 0.001), but not associated with the presence of cough and fatigue. Diabetic patients had higher odds of reporting diarrhea (1.637, 95% CI: 1.351-1.982, p < 0.001). Symptoms from Omicron infection may last for more than 4 weeks and symptom profiles vary from week to week. Vaccination and comorbidity affect the symptom profiles.

Spontaneous pneumomediastinum in a COVID-19 patient after renal transplantation: a case report and literature review (preprint)

Background: Spontaneous pneumomediastinum is a rare complication in COVID-19. Severe pneumonia complicated with pneumomediastinum after renal transplantation is rarely reported. Here we report a case of pneumomediastinum before invasive mechanical ventilation (IMV) in a COVID-19 patient with long-term immunosuppressive therapy after renal transplantation. Case presentation: A 57-year-old man was admitted to our center with the main complaint of “fever and dyspnea for 5 days”. His past medical history was notable for renal transplantation and with long-term immunosuppressive and anti-rejection therapy. We made the diagnosis as COVID-19 pneumonia (severe type). We managed the patient with high flow nasal cannulae (HFNC), oral dexamethasone, broad-spectrum antibiotic, prophylactic anticoagulation, and anti-viral therapy with reduced dose of azvudine due to severe renal insufficiency. During hospitalization, the patient suffered from several times of aggravation of dyspnea. First bedside chest X-ray showed suspicious pneumomediastinum and subcutaneous emphysema, and the gas in the mediastinum gradually increased. The patient’s status deteriorated rapidly, we performed urgent trachea intubation and mechanical ventilation with low tidal volume lung-protective model and performed mediastinal decompression by suprasternal drainage. Despite our active rescue efforts, the patient still died of severe infection and multiple organ failure. Conclusions: In conclusion, we are the first to report spontaneous pneumomediastinum in a renal transplant recipient with severe COVID-19 pneumonia. This case reminds us that pneumomediastinum is a severe complication and a poor prognostic factor of COVID-19 pneumonia, especially when it occurred without positive pressure ventilation and in immunocompromised patients.