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Virus: Infection Characteristics, Tracking and Epidemiology

Stay updated on relevant changes and variations in the SARS-CoV-2 virus. The CDC offers multiple resources for tracking mutations and following statistical. This data can help practicing allergist / immunologists plan for the needs of incoming patients and develop treatment protocols for appropriate patient care.

CDC COVID-19 Data Tracker: Home

CDC COVID-19 Data Tracker: Pediatric Data

See the CDC's list of SARS-CoV-2 Variant Classifications and Definitions and the Variant Proportions Tracker for more detailed information on the variants currently in circulation. 

The CDC has developed updates on ventilation for reducing exposure to respiratory viruses in indoor spaces. This includes an Interactive Home Ventilation Tool. Ventilation Can Reduce Exposure to Respiratory Viruses in Indoor Spaces | CDC - March 22, 2024

A nationwide cohort study involving the entire Danish population 12 years and older who were SARS-CoV-2 positive (1,775,639 individuals) found that individuals who tested positive were 24% less likely to have any psychiatric disease and only 5% more likely to have any neurologic disorder. Among patients hospitalized for COVID-19, however, the risk for psychiatric disorders was 2.1-fold higher and 2.4-fold higher for neurological disorders. This study did not compare individuals hospitalized for other conditions to the COVID population, but it did show that there is little to no risk for COVID-19 patients to develop psychiatric or neurologic disorders unless they had more severe disease. SARS-CoV-2 Infection and Risk of Postacute Psychiatric and Neurologic Diagnoses | Neurology - March 12, 2024

This study evaluated over 10 million Korean and over 12 million Japanese adults including those with COVID-19 compared to patients with influenza or no infection and found an increased risk of autoimmune inflammatory rheumatic disease in those infected with COVID-19 compared to matched uninfected controls (adjusted hazard ratio, 1.25 (95% CI, 1.18,1.31). Long-Term Autoimmune Inflammatory Rheumatic Outcomes of COVID-19: A Binational Cohort Study: Annals of Internal Medicine: Vol 177, No 3 ( - March 5, 2024

A strain of SARS-CoV-2 with more than 30 changes in its spike protein compared to XBB.1.5 has been identified in 9 patients in South Africa since September of 2023. This variant is known as BA.2.87.1 No cases have been reported outside of South Africa. The fact that only 9 cases have been reported over a 5 month period suggests that this variant is not as infectious as XBB.1.5, but not much is known. CDC Tracking BA.2.87.1, New Omicron Subvariant With Potential to Evade Immunity | Vaccination | JAMA | JAMA Network – February 28, 2024

This study assessed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A viral loads relative to symptom duration in symptomatic adults (≥16 years) presenting for testing in Georgia (4/2022–4/2023; Omicron variant predominant). Of 348 newly-diagnosed SARS-CoV-2 PCR-positive individuals (65.5% women, median 39.2 years), 317/348 (91.1%) had a history of vaccination, natural infection, or both. Antigen rapid diagnostic test sensitivity estimates were 30.0%–60.0% on the first day, 59.2%–74.8% on the third day, and 80.0%–93.3% on the fourth day of symptoms. In 74 influenza A PCR-positive individuals (55.4% women; median 35.0 years), median influenza viral loads peaked on the second day of symptoms. New Normal: Delayed Peak SARS-CoV-2 Viral Loads Relative to Symptom Onset and Implications for COVID-19 Testing Programs | Clinical Infectious Diseases | Oxford Academic ( – February 15, 2024

This issue of Nature Cellular and Molecular Immunology has several review articles on the SARS-CoV-2 immune response.  Here are a few. B-cell and antibody responses to SARS-CoV-2: infection, vaccination, and hybrid immunity | Cellular & Molecular Immunology (, Silent battles: immune responses in asymptomatic SARS-CoV-2 infection | Cellular & Molecular Immunology (, SARS-CoV-2 and innate immunity: the good, the bad, and the “goldilocks” | Cellular & Molecular Immunology ( - January 15, 2024