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October 19, 2023

Clinical Reports

  • Neurologic Effects of SARS-CoV-2 Transmitted among Dogs
    SARS-CoV-2 induces illness and death in humans by causing systemic infections. Evidence suggests that SARS-CoV-2 can induce brain pathology in humans and other hosts. In this study, researchers used a canine transmission model to examine histopathologic changes in the brains of dogs infected with SARS-CoV-2. Researchers observed substantial brain pathology in SARS-CoV-2–infected dogs, particularly involving blood–brain barrier damage resembling small vessel disease, including changes in tight junction proteins, reduced laminin levels, and decreased pericyte coverage. Furthermore, we detected phosphorylated tau, a marker of neurodegenerative disease, indicating a potential link between SARS-CoV-2–associated small vessel disease and neurodegeneration. These findings of degenerative changes in the dog brain during SARS-CoV-2 infection emphasize the potential for transmission to other hosts and induction of similar signs and symptoms. The dynamic brain changes in dogs highlight that even asymptomatic individuals infected with SARS-CoV-2 may develop neuropathologic changes in the brain.
  • Serotonin reduction in post-acute sequelae of viral infection
    Long COVID is associated with reduced circulating serotonin levels. Serotonin depletion is driven by viral RNA-induced type I interferons (IFNs). IFNs reduce serotonin through diminished tryptophan uptake and hypercoagulability. Peripheral serotonin deficiency impairs cognition via reduced vagal signaling

Antiviral Therapeutics and Vaccines

  • Effectiveness of Monovalent mRNA Vaccines Against Omicron XBB Infection in Singaporean Children Younger Than 5 Years
    In this population-wide cohort study including all Singaporean children aged 1 through 4 years (N = 121 628; 21 015 956 person-days) during an Omicron XBB surge, mRNA vaccine effectiveness against confirmed infection was 63.3% in fully vaccinated, infection-naive children and 74.6% against reinfections in previously infected children with at least 1 vaccine dose. Study results suggest that completion of a primary mRNA vaccine series provided protection against SARS-CoV-2 infection in children younger than 5 years, even during community circulation of the Omicron XBB variant.


  • High Influenza Incidence and Disease Severity Among Children and Adolescents Aged <18 Years ― United States, 2022–23 Season
    The 2022–23 influenza season began early, coinciding with circulation of other respiratory viruses. High hospitalization rates among children and adolescents were observed. Among children and adolescents aged <18 years, 2022–23 was a high severity influenza season compared with thresholds based on previous seasons’ data; influenza-associated medical visits and hospitalizations met or exceeded incidence in previous seasons. CDC recommends that all persons aged ≥6 months without contraindications should receive the annual seasonal influenza vaccine, ideally by the end of October.
  • The effectiveness of COVID-19 vaccine in the prevention of post-COVID conditions: a systematic literature review and meta-analysis of the latest research
    Researchers performed a systematic literature review and meta-analysis on the effectiveness of coronavirus disease 2019 (COVID-19) vaccination against post-COVID conditions (long COVID) among fully vaccinated individuals. Researchers searched PubMed, Cumulative Index to Nursing and Allied Health, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science from December 1, 2019, to June 2, 2023, for studies evaluating the COVID-19 vaccine effectiveness (VE) against post-COVID conditions among fully vaccinated individuals who received two doses of COVID-19 vaccine. A post-COVID condition was defined as any symptom that was present four or more weeks after COVID-19 infection. We calculated the pooled diagnostic odds ratio (DOR) (95% confidence interval) for post-COVID conditions between fully vaccinated and unvaccinated individuals. Vaccine effectiveness was estimated as 100% x (1-DOR). Thirty-two studies with 775,931 individuals evaluated the effect of vaccination on post-COVID conditions, of which, twenty-four studies were included in the meta-analysis. The pooled DOR for post-COVID conditions among fully vaccinated individuals was 0.680 (95% CI: 0.523–0.885) with an estimated VE of 32.0% (11.5%–47.7%). Vaccine effectiveness was 36.9% (23.1%–48.2%) among those who received two doses of COVID-19 vaccine before COVID-19 infection and 68.7% (64.7%–72.2%) among those who received three doses before COVID-19 infection. The stratified analysis demonstrated no protection against post-COVID conditions among those who received COVID-19 vaccination after COVID-19 infection. Receiving a complete COVID-19 vaccination prior to contracting the virus resulted in a significant reduction in post-COVID conditions throughout the study period, including during the Omicron era. Vaccine effectiveness demonstrated an increase when supplementary doses were administered.
  • Incidence and Impact of Acute Pericarditis in Hospitalized Patients With COVID‐19
    Acute pericarditis (AP) is considered a cardiovascular complication in patients with COVID‐19. Researchers aimed to assess the incidence, associated complications, and clinical impact of AP on hospitalized patients with COVID‐19. In this retrospective cohort study, International Classification of Diseases, Tenthth Revision, Clinical Modification (ICD‐10) codes were used to identify patients with COVID‐19 with or without AP in the National Inpatient Sample 2020 database. We compared outcomes between AP and non‐AP groups before and after propensity‐score matching for patient and hospital demographics and relevant comorbidities. A total of 211 619 patients with a primary diagnosis of COVID‐19 were identified, including 983 (0.46%) patients who had a secondary diagnosis of AP. Before matching, patients with COVID‐19 with AP were younger (59.93±19.24 years old versus 64.29±16.82 years old) and more likely to have anemia (40.5% versus 19.9%), cancer (6.7% versus 3.6%), and chronic kidney disease (29.3% versus 19.6%) (all P<0.05). After matching, patients with COVID‐19 with AP (n=980), when compared with the matched non‐AP group (n=2936), had higher rates of mortality (21.3% versus 11.1%, P<0.001), cardiac arrest (5.0% versus 2.6%, P<0.001), cardiogenic shock (4.2% versus 0.5%, P<0.001), ventricular arrhythmia (4.7% versus 1.9%, P<0.001), acute kidney injury (38.3% versus 28.9%, P<0.001), acute congestive heart failure (14.3% versus 4.8%, P<0.001), and longer length of stay (7.00±10.00 days versus 5.00±7.00 days, P<0.001) and higher total charges ($75066.5±$130831.3 versus $44824.0±$63660.5, P<0.001). In hospitalized patients with COVID‐19, AP is a rare but severe in‐hospital complication and is associated with worse in‐hospital outcomes.
  • Prevalence and risk factors for long COVID and post-COVID-19 condition in Africa: a systematic review
    An improved estimation of the clinical sequelae of SARS-CoV-2 infection is crucial in African countries, where the subject has received little attention despite more than 12 million reported cases and evidence that many more people were infected. Researchers reviewed the evidence on prevalence, associated risk factors for long COVID, and systemic or sociocultural determinants of reporting long COVID. Researchers conducted a systematic review, searching PubMed, the Living Overview of Evidence platform, and grey literature sources for publications from Dec 1, 2019, to Nov 23, 2022. They included articles published in English, French, Spanish, or Portuguese that reported on any study type in Africa with participants of any age who had symptoms for 4 weeks or more after an acute SARS-CoV-2 infection. They also excluded secondary research, comments, and correspondence. Screening and data extraction were performed by two reviewers. Summary estimates were extracted, including sociodemographic factors, medical history, prevalence of persistent symptoms, and symptoms and associated factors. Results were analysed descriptively. The study was registered on the Open Science Framework platform. This search yielded 294 articles, of which 24 peer-reviewed manuscripts were included, reporting on 9712 patients from eight African countries. Only one study exclusively recruited children, and one other study included children as part of their study population. Studies indicated moderate to low risk of bias. Prevalence of long COVID varied widely, from 2% in Ghana to 86% in Egypt. Long COVID was positively associated with female sex, older age, non-Black ethnicity, low level of education, and the severity of acute infection and underlying comorbidity. HIV and tuberculosis were not identified as risk factors. Factors influencing reporting included absence of awareness, inadequate clinical data and diagnostics, and little access to health-care services. In Africa, research on long COVID is scarce, particularly among children, who represent the majority of the population. However, existing studies show a substantial prevalence across settings, emphasizing the importance of vaccination and other prevention strategies to avert the effects of long COVID on individual wellbeing, the increased strain on health systems, and the potential negative effects on economically vulnerable populations. At a global level, including African countries, tools for research on long COVID need to be harmonised to maximise the usefulness of the data collected.

Situation Dashboards


World Health Organization (WHO)

Novel Coronavirus (COVID-19) Situation from World Health Organization (WHO)

Johns Hopkins University (JHU)

Coronavirus COVID-19 Global Cases by the Center for Systems Science and Engineering (CSSE) at JHU

COVID-19 in US and Canada

1Point3Acres Real-Time Coronavirus (COVID-19) Updates in US and Canada with Credible Sources

Genomic Epidemiology COVID-19

Genomic Epidemiology of (COVID-19) Maintained by the Nextstrain team, enabled by data from GISAID.

Sources for COVID-19 Information


World Health Organization (WHO)


Centers for Disease Control, US


International Society for Infectious Diseases


This Week in Virology (TWIV)

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