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 current predominant variant is KP.3.1.1, still a subvariant of Omicron. Even though this variant has only a few mutations compared to JN.1, it appears to be fueling a summer wave that may be greater than 2023, based on wastewater analysis and hospitalization rates. (Various sources including CDC).
This study from South Korea, like others, noted significantly increased risk of various autoimmune and autoinflammatory connective tissue disorders following COVID-19, especially among those with severe disease. Patient were followed for 180 days after infection. Vaccination reduced the risk. - December 4, 2024
While pre-existing anti-interferon alpha (anti-IFN-α) autoantibodies in the circulation are associated with severe disease, this study suggests that similar autoantibodies in other tissues may actually predict improved response to infection, specifically those in the nasal mucosa. Induction of the autoantibodies was associated with a reduction in IFN-α, perhaps reducing the inflammatory response. - November 6, 2024
The risk of major adverse cardiac events (MACE) which includes MI, stroke and all-cause mortality is twice as high in COVID-19 cases at all levels of severity and 3.85 times as high in those hospitalized with COVID-19. MACE risks among cases without a history of cardiovascular disease was even higher that that observed in patients with cardiovascular disease without COVID-19. - October 9, 2024
This case-control study among 68,000 patients with chronic lung disease (asthma, COPD, bronchiectasis, and pulmonary fibrosis) found an increased risk of infection, hospitalization and severe disease among those with chronic lung disease, including asthma, compared to controls without lung disease in both the Delta and Omicron waves. A fourth dose of vaccine was associated with a lower risk compared to those with three doses. - June 10, 2024
Maternal vaccination improves outcomes for infants <6 months of age. Infants <6 months of age with COVID-19 have hospitalization rates comparable to adults ages 65-74, only those over 75 years of age have higher hospitalization rates. Disease can be severe, with 22% admitted to the ICU. The mothers of 87.5% of hospitalized infants from the COVID-NET surveillance study performed in 90 counties across 12 states had no documentation of vaccination. All the infants who died (9/1148) were born to mothers without vaccination. COVID-19–Associated Hospitalizations and Maternal Vaccination Among Infants Aged 6 Months — COVID-NET, 12 States, October 2022–April 2024 | MMWR - September 26, 2024
COVID-19 drops to 10th leading cause of death in adults in 2023. The numbers of deaths, which were still over 3 million, was 68.9% lower than in 2022. The overall death rate was highest among non-Hispanic Black persons. Mortality in the United States — Provisional Data, 2023 | MMWR (cdc.gov) – August 8, 2024
Cannabis use associated with higher risk of hospitalization and ICU admission from COVID-19 in this large cohort study. Cannabis, Tobacco Use, and COVID-19 Outcomes | Substance Use and Addiction Medicine | JAMA Network Open | JAMA Network - June 21, 2024
COVID-19 infection is associated with a significantly higher incidence of new-onset asthma in children regardless of vaccination status. There is also emerging evidence that adults are also at risk. This was a retrospective cohort study design, and the vaccinated children were slightly less likely to have new-onset asthma but the hazard ratios in vaccinated children was 2.25 compared to the HR in unvaccinated of 2.74. The cohorts included children with and without COVID-19 infection. The association between COVID-19 vaccine/infection and new-onset asthma in children - based on the global TriNetX database - PubMed (nih.gov) - June 21, 2024
The study noted that subway mask mandates were cost-effective (net cost per averted death) for all viral strains up to March 2022. Cost-effectiveness of mask mandates on subways to prevent SARS-CoV-2 transmission in the United States - PubMed (nih.gov) – May 15, 2024
We know that COVID-19 infection impacts taste and smell in some patients, particularly with the earlier viral serotypes. In this cross-sectional study of 340 individuals with and 434 individuals without prior COVID-19, taste function did not differ between individuals who had contracted COVID-19 one year earlier and those who had not, whereas some olfactory dysfunction was present in 30.3% of individuals with prior COVID-19 but only 21.0% of individuals with no history of infection. These findings suggest that long-term taste loss perceived by many patients with COVID-19 likely reflects the loss of flavor sensations from odorant molecules reaching a damaged olfactory epithelium via the nasopharynx rather than the taste buds. Long-Term Taste and Smell Outcomes After COVID-19 | Otolaryngology | JAMA Network Open | JAMA Network - April 23, 2024
This retrospective cohort study examined children ages 1 to 16 within the Children’s Hospital of Philadelphia Care Network who received polymerase chain reaction (PCR) testing for SARS-CoV-2 between March 1, 2020 and February 28, 2021. There were 27 423 subjects included in the study. In adjusted analyses, SARS-CoV-2 PCR positivity had no significant effect on the hazard of new asthma diagnosis (hazard ratio [HR]: 0.96; P = .79). COVID-19 and Asthma Onset in Children | Pediatrics | American Academy of Pediatrics (aap.org) - April 12 2024
As we all recall, various states mandated masks and vaccine or testing during periods of SARS-CoV-2 surge. We all wonder about the effectiveness of such mandates. Facing a surge of COVID-19 cases in late August 2021, the U.S. state of Illinois re-enacted its COVID-19 mask mandate for the general public and issued a requirement for workers in certain professions to be vaccinated against COVID-19 or undergo weekly testing. The mask mandate required any individual, regardless of their vaccination status, to wear a well-fitting mask in an indoor setting. These authors used Illinois Department of Public Health's COVID-19 confirmed case and vaccination data and investigated scenarios where masking and vaccination would have been reduced to mimic what would have happened had the mask mandate or vaccine requirement not been put in place. The study examined a range of potential reductions in masking and vaccination mimicking potential scenarios had the mask mandate or vaccine requirement not been enacted. They estimated COVID-19 cases and hospitalizations averted by changes in masking and vaccination during the period covering October 20 to December 20, 2021. The authors found that the announcement and implementation of a mask mandate are likely to correlate with a strong protective effect at reducing COVID-19 burden and the announcement of a vaccinate-or-test requirement among frontline professionals is likely to correlate with a more modest protective effect at reducing COVID-19 burden. In our most conservative scenario, we estimated that from the period of October 20 to December 20, 2021, the mask mandate likely prevented approximately 58,000 cases and 1,175 hospitalizations, while the vaccinate-or-test requirement may have prevented at most approximately 24,000 cases and 475 hospitalizations. Estimated public health impact of concurrent mask mandate and vaccinate-or-test requirement in Illinois, October to December 2021 - PubMed (nih.gov) - April 12, 2024
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
Obstructive sleep apnea is a causal risk factor for severe COVID-19 disease, predominately due to higher BMI. Encourage these patients to be vaccinated. Genetic Analysis of Obstructive Sleep Apnea and Its Relationship with Severe COVID-19 | Annals of the American Thoracic Society (atsjournals.org) - March 12, 2023
The risk of autoimmune inflammatory rheumatic diseases (AIRD) in this very large study of Korean and Japanese men found that those infected with COVID-19 were 25% more likely to have incident AIRD compared to uninfected individuals and 30% more likely than those infected with influenza. The risk was higher with more severe COVID-19 disease. Long-Term Autoimmune Inflammatory Rheumatic Outcomes of COVID-19: A Binational Cohort Study: Annals of Internal Medicine: Vol 177, No 3 (acpjournals.org) - March 5, 2024
Current variants of interest continue to derive from the Omicron stage and include KP.3 (36.9% and increasing), KP.2 (21.5% and declining) and LB.1 (14.9% and slowly increasing). CDC COVID Data Tracker: Variant Proportions accessed 7/7/24. The FDA vaccine advisory committee recommended that the fall booster be based on the KP.2 variant, but shortly after that Peter Marks, MD PhD, the head of the FDA vaccine section recommended it be based on the KP.3 strain if possible. Both mRNA vaccines will be based on either KP.2 or KP.3 (depending on time necessary to develop the vaccine) but because Novavax is a different type of vaccine, theirs will be based on the JN.1 strain which was predominant during this past winter but now makes up <5% of infections.
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 (acpjournals.org) - 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 (oup.com) – 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 (nature.com), Silent battles: immune responses in asymptomatic SARS-CoV-2 infection | Cellular & Molecular Immunology (nature.com), SARS-CoV-2 and innate immunity: the good, the bad, and the “goldilocks” | Cellular & Molecular Immunology (nature.com). - January 15, 2024