Risultati per: Ipotesi sull’origine di Omicron e sua evoluzione

Experts detected a strain of SARS-CoV-2 with more than 30 changes in its spike protein compared with Omicron subvariant XBB.1.5, the US Centers for Disease Control and Prevention (CDC) announced. The newer Omicron subvariant, known as BA.2.87.1, has infected at least 9 people in South Africa since September 2023. No cases have been reported in the US or outside South Africa, the CDC noted in its update.

Annals of Internal Medicine, Ahead of Print.

Annals of Internal Medicine, Ahead of Print.

This cohort study compares the mortality and hospitalization risks among patients with vs without solid cancer and diagnosed with COVID-19 during the period when the Omicron variant was dominant.

Objectives
The rapid spread of the SARS-CoV-2 Omicron variant has raised concerns regarding waning vaccine-induced immunity and durability. We evaluated protection of the third-dose and fourth-dose mRNA vaccines against SARS-CoV-2 Omicron subvariant and its sublineages.

Design
Systematic review and meta-analysis.

Data sources
Electronic databases and other resources (PubMed, Embase, CENTRAL, MEDLINE, CINAHL PLUS, APA PsycINFO, Web of Science, Scopus, ScienceDirect, MedRxiv and bioRxiv) were searched until December 2022.

Study eligibility criteria
We included studies that assessed the effectiveness of mRNA vaccine booster doses against SARS-CoV-2 infection and severe COVID-19 outcomes caused by the subvariant.

Data extraction and synthesis
Estimates of vaccine effectiveness (VE) at different time points after the third-dose and fourth-dose vaccination were extracted. Random-effects meta-analysis was used to compare VE of the third dose versus the primary series, no vaccination and the fourth dose at different time points. The certainty of the evidence was assessed by Grading of Recommendations, Assessments, Development and Evaluation approach.

Results
This review included 50 studies. The third-dose VE, compared with the primary series, against SARS-CoV-2 infection was 48.86% (95% CI 44.90% to 52.82%, low certainty) at ≥14 days, and gradually decreased to 38.01% (95% CI 13.90% to 62.13%, very low certainty) at ≥90 days after the third-dose vaccination. The fourth-dose VE peaked at 14–30 days (56.70% (95% CI 50.36% to 63.04%), moderate certainty), then quickly declined at 61–90 days (22% (95% CI 6.40% to 37.60%), low certainty). Compared with no vaccination, the third-dose VE was 75.84% (95% CI 40.56% to 111.12%, low certainty) against BA.1 infection, and 70.41% (95% CI 49.94% to 90.88%, low certainty) against BA.2 infection at ≥7 days after the third-dose vaccination. The third-dose VE against hospitalisation remained stable over time and maintained 79.30% (95% CI 58.65% to 99.94%, moderate certainty) at 91–120 days. The fourth-dose VE up to 60 days was 67.54% (95% CI 59.76% to 75.33%, moderate certainty) for hospitalisation and 77.88% (95% CI 72.55% to 83.21%, moderate certainty) for death.

Conclusion
The boosters provided substantial protection against severe COVID-19 outcomes for at least 6 months, although the duration of protection remains uncertain, suggesting the need for a booster dose within 6 months of the third-dose or fourth-dose vaccination. However, the certainty of evidence in our VE estimates varied from very low to moderate, indicating significant heterogeneity among studies that should be considered when interpreting the findings for public health policies.

PROSPERO registration number
CRD42023376698.

Circulation, Volume 148, Issue Suppl_1, Page A15960-A15960, November 6, 2023. Introduction:Hospitalization for COVID-19 is often associated with myocardial injury (elevated cardiac troponin [cTn]). In the initial pandemic waves, patients with myocardial injury had increased likelihood of cardiovascular complications and inpatient mortality; however, the differences in impact of distinct subtypes of myocardial injury on mortality is unclear. In addition, little is known about how these outcomes compare with the subsequent, milder, Omicron wave.Methods:Utilizing Mayo Clinic enterprise patients we developed algorithms based on diagnostic/procedural codes, cTn levels, and temporal relationships to positive COVID-19 PCR tests, to determine 5 common subtypes of myocardial injury: stress cardiomyopathy, myocarditis, pericarditis, pulmonary embolism, and myocardial infarction. We examined hospitalized adults with COVID-19; those with elevated cTn designated as cases and others as controls. We fitted Cox models using the following covariates: spline transformed age, sex, race, ethnicity, index date and clinical comorbidities. Patients were analyzed based on admission dates coinciding with either the Alpha-Delta or Omicron waves.Results:Across both wave cohorts, hospitalized patients with acute COVID-19 complicated by myocardial injury had an increased risk of mortality compared to those without (Figure). Patients with one of the 5 subtypes examined tended to have higher risk than those in the “other myocardial injury” category. Admission during the Omicron wave, compared to the Alpha-Delta waves, tended to have higher mortality risk in all subtypes except myocarditis.Conclusions:Our algorithms successfully identified subgroups of myocardial injury in patients hospitalized with acute COVID-19 leading to stratification of mortality risk. Surprisingly, among hospitalized patients during the Omicron wave, myocardial injury of most subtypes was tended to have increased risk of mortality compared to the Alpha-Delta waves.

Si conferma la netta prevalenza di EG.5

Crescono i contagi e anche se il virus non colpisce come prima resta sempre un rischio per le persone fragili e gli anziani.

Dufour et al highlighted that the effect of COVID-19 in patients with cirrhosis is derived from the prevaccination era and suggested that the impact of Omicron infection in patients with cirrhosis needs to be elucidated.1 We agree with the author that previous studies have reported significant morbidity and mortality in patients with cirrhosis infected with SARS CoV-2 in the prevaccination era.2–7 To our knowledge, no studies have assessed the impact of Omicron infection in patients with cirrhosis. Therefore, we aimed to compare the outcomes of Omicron infection among patients with cirrhosis and without cirrhosis. We retrospectively included non-cirrhotic (NC) patients and patients with cirrhosis from 1 January 2022 to 1 March 2022 diagnosed with Omicron infection. Omicron BA.1 variant was identified based on the S-gene dropout on the reverse transcriptase PCR test. In the absence…

We read with interest about the prognostic significance of liver function abnormalities in SARS-CoV-2 infection.1 2 Although patients with underlying cirrhosis have an increased risk of death following COVID-19, mRNA vaccine administration is associated with an excellent reduction in mortality.3 4 We aimed to determine the association of the prevalence of the Alpha, Delta and Omicron variants and effectiveness of the BNT162b2 or 1273-mRNA vaccines among participants with cirrhosis. We performed a test-negative case–control study of participants with cirrhosis in the Veterans Outcomes and Costs Associated with Liver disease cohort, who had a SARS-CoV-2 PCR between 1 February 2021 and 21 January 2022.5–7 Participants with a positive PCR were considered as cases, and others, as controls. Propensity score (PS) matching was used to match cases and controls, with PS of being a case derived from…

Molecola che regola la forma delle proteine

This Medical News story discusses the updated COVID-19 vaccines expected in the US this fall.

This Viewpoint discusses reports from China after its zero COVID-19 policy ended in December 2022.

Objective
To determine the SARS-CoV-2 seroprevalence among school workers within the Greater Vancouver area, British Columbia, Canada, after the first Omicron wave.

Design
Cross-sectional study by online questionnaire, with blood serology testing.

Setting
Three main school districts (Vancouver, Richmond and Delta) in the Vancouver metropolitan area.

Participants
Active school staff enrolled from January to April 2022, with serology testing between 27 January and 8 April 2022. Seroprevalence estimates were compared with data obtained from Canadian blood donors weighted over the same sampling period, age, sex and postal code distribution.

Primary and secondary outcomes
SARS-CoV-2 nucleocapsid antibody testing results adjusted for test sensitivity and specificity, and regional variation across school districts using Bayesian models.

Results
Of 1850 school staff enrolled, 65.8% (1214/1845) reported close contact with a COVID-19 case outside the household. Of those close contacts, 51.5% (625/1214) were a student and 54.9% (666/1214) were a coworker. Cumulative incidence of COVID-19 positive testing by self-reported nucleic acid or rapid antigen testing since the beginning of the pandemic was 15.8% (291/1845). In a representative sample of 1620 school staff who completed serology testing (87.6%), the adjusted seroprevalence was 26.5% (95% CrI 23.9% to 29.3%), compared with 32.4% (95% CrI 30.6% to 34.5%) among 7164 blood donors.

Conclusion
Despite frequent COVID-19 exposures reported, SARS-CoV-2 seroprevalence among school staff in this setting remained no greater than the community reference group. Results are consistent with the premise that many infections were acquired outside the school setting, even with Omicron.

New England Journal of Medicine, Volume 388, Issue 18, Page 1726-1727, May 2023.