Duration of viable virus shedding and polymerase chain reaction positivity of the SARS-CoV-2 Omicron variant in the upper respiratory tract: a systematic review and meta-analysis

ABSTRACT Real-world evidence on the effectiveness of COVID-19 vaccines marketed in China against the Omicron BA.2.2 variant remains scarce. A case–control study was conducted to estimate the vaccine effectiveness (VE) of COVID-19 vaccines marketed in China (inactivated vaccines, an Ad5-nCoV vaccine, and a recombinant protein vaccine). There were 414 cases infected with SARS-CoV-2 and 828 close contacts whose test results were consecutively negative as controls during the outbreak of the Omicron variant in Lu’an City, Anhui Province, China, in April 2022. The overall adjusted VE against Omicron BA.2.2 variant infection in the vaccinated group with any COVID-19 vaccine was 35.0% (95% CI: −9.1–61.3%), whereas the adjusted VE for booster vaccination was 51.6% (95% CI: 15.2–72.4%). Subgroup analysis showed that the overall adjusted VE of the Ad5-nCoV vaccine (65.8%, 95% CI: 12.8–86.6%) during the outbreak while any dose of inactivated vaccines and recombinant protein vaccine offered no protection. The adjusted VE of three-dose inactivated vaccines was 48.0% (95% CI: 8.0–70.6%), and the two-dose Ad5-nCoV vaccine was 62.9% (95% CI: 1.8–86%). There is no protection from a three-dose recombinant protein vaccine. COVID-19 vaccines offered 46.8% (95% CI: 9.5–68.7%) protection from infection within six months. There were statistically significant differences between the VEs of heterologous booster (VE = 76.4%, 95% CI: 14.3–93.5%) and homologous booster vaccination (VE = 51.8%, 95% CI: 9.6–74.3%) (P = .036). Booster vaccination of COVID-19 vaccines offered more protection than full vaccination. A booster vaccination campaign for a booster dose after three doses of a recombinant protein vaccine must be urgently conducted.

https://doi.org/10.1080/21645515.2023.2194189

Effectiveness of a booster dose of COVID-19 vaccines during an outbreak of SARS-CoV-2 Omicron BA.2.2 in China: A case–control study

Atopic dermatitis (AD) is a common highly pruritic chronic inflammatory skin disorder affecting 5–20% of children worldwide, while the prevalence in adults varies from 7 to 10%. Patients with AD experience intense pruritus that could lead to sleep disturbance and impaired quality of life. Here, we analyze the pathophysiology of itchiness in AD. We extensively review the histamine-dependent and histamine-independent pruritogens. Several receptors, substance P, secreted molecules, chemokines, and cytokines are involved as mediators in chronic itch. We also, summarize the new emerging antipruritic drugs in atopic dermatitis.

/pdf/pruritogenic-mediators-and-new-antipruritic-drugs-in-atopic-1qlpdheh.pdf

Pruritogenic Mediators and New Antipruritic Drugs in Atopic Dermatitis

We aimed to explore the influence of comorbid asthma on the risk for mortality among patients with coronavirus disease 2019 (COVID-19) in Asia by using a meta-analysis. Electronic databases were systematically searched for eligible studies. The pooled odds ratio (OR) with 95% confidence interval (CI) was estimated by using a random-effect model. An inconsistency index (I2) was utilized to assess the statistical heterogeneity. A total of 103 eligible studies with 198,078 COVID-19 patients were enrolled in the meta-analysis; our results demonstrated that comorbid asthma was significantly related to an increased risk for COVID-19 mortality in Asia (pooled OR = 1.42, 95% CI: 1.20–1.68; I2 = 70%, p < 0.01). Subgroup analyses by the proportion of males, setting, and sample sizes generated consistent findings. Meta-regression indicated that male proportion might be the possible sources of heterogeneity. A sensitivity analysis exhibited the reliability and stability of the overall results. Both Begg’s analysis (p = 0.835) and Egger’s analysis (p = 0.847) revealed that publication bias might not exist. In conclusion, COVID-19 patients with comorbid asthma might bear a higher risk for mortality in Asia, at least among non-elderly individuals.

/pdf/comorbid-asthma-increased-the-risk-for-covid-19-mortality-in-gzp0ejj2.pdf

Comorbid Asthma Increased the Risk for COVID-19 Mortality in Asia: A Meta-Analysis

Abstract Background COVID-19 vaccine policy relied on observational vaccine-effectiveness (VE) studies conducted amid rapid variant turnover, evolving schedules, and shifting surveillance, yielding substantial heterogeneity in methodological approaches across studies. Prior reviews emphasised pooled or variant-specific VE, with limited attention to how methodological practice varied across countries and over time. Yet, understanding the landscape of methodological practices used during this period is essential for identifying opportunities to improve VE study design and conduct in future pandemic responses. This review systematically characterises the methodological practices in registry-based observational COVID-19 VE studies (2021–2024), documenting patterns in study design, statistical approaches, and analytical choices to establish an empirical foundation for methodological development in pandemic vaccine evaluation. Methods We ran a PRISMA-guided search of PubMed and Embase (via Ovid) from inception to Oct 14, 2024, for peer-reviewed observational studies estimating COVID-19 VE in routine (non-trial) settings that leveraged administrative/registry data (e.g., immunisation registries, laboratory/PCR databases, EHR/claims, hospitalisation/mortality registries, national-ID–linked datasets) and reported sufficient methodological detail to classify design, estimator, treatment of time, adjustment/matching/weighting, and sensitivity/validation checks. We excluded randomised trials; studies without administrative/registry data or confined to specialised populations; non-English publications; and duplicate analyses of the same cohort/time window. Descriptive summaries are presented overall, by calendar year, and by World Bank income group. Results 253 studies from 61 countries met eligibility; most were from high-income settings (187/253, 73.9%). The median publication lag was 257 days (IQR 157–421), lengthening from 141 days in 2021 to 673 in 2024, while median cohort size declined over time. Cohorts (46.6%) and test-negative designs (43.1%) dominated; target-trial emulations (2.0%) and quasi-experimental studies (1.2%) were uncommon. Logistic regression (56.1%) and Cox models (24.8%) comprised the majority of primary estimator. Adjustment emphasised demographics, comorbidity, calendar time, and geography; variables proximate to testing behaviour and exposure opportunity were less frequent. Most studies reported no matching/weighting (155/253, 61.2%); among those that did, exact matching predominated and weighting was rare. Sensitivity analyses were not described in 98/253 (38.7%) of studies. Endpoints concentrated on infection, hospitalisation, and mortality, while variant-resolved analyses waned as PCR testing and sequencing contracted. Conclusions Observational COVID-19 vaccine VE studies scaled rapidly where registries existed, but remained concentrated in high-income settings, relied on a narrow estimator set, and infrequently applied validity checks. Strengthening privacy-preserving linkages (including sequencing), aligning designs to target-trial principles with marginal weighting, and normalising a lean validity toolkit could enhance interpretability and policy relevance. Funding This research is supported by the National Research Foundation Singapore under its Clinician Scientist-Individual Research Grant (MOH-001572) and administered by the Singapore Ministry of Health’s National Medical Research Council. J.T.L. is supported by the Ministry of Education (MOE), Singapore Start-up Grant. L.E.W. is supported by the National Medical Research Council through the Clinician Scientist New Investigator Award. 

pdf/approaches-for-estimating-covid-19-vaccine-effectiveness-p0tbmahhmap4.pdf

Approaches for estimating COVID-19 vaccine effectiveness using observational data in administrative databases: a systematic review

Inhibitory effects of antibiotic-induced gut microbiota depletion on acute itch behavior in mice

Background: Real-world evidence on the effectiveness of inactivated vaccines against the Delta and Omicron (BA.2.38) variants remains scarce. Methods: A retrospective cohort study was conducted to estimate the adjusted vaccine effectiveness (aVE) of one, two, and three doses of inactivated vaccines in attenuating pneumonia, severe COVID-19, and the duration of viral shedding in Delta and Omicron cases using modified Poisson and linear regression as appropriate. Results: A total of 561 COVID-19 cases were included (59.2% Delta and 40.8% Omicron). In total, 56.4% (184) of Delta and 12.0% (27) of Omicron cases had COVID-19 pneumonia. In the two-dose vaccinated population, 1.4% of Delta and 89.1% of Omicron cases were vaccinated for more than 6 months. In Delta cases, the two-dose aVE was 52% (95% confidence interval, 39–63%) against pneumonia and 61% (15%, 82%) against severe disease. Two-dose vaccination reduced the duration of viral shedding in Delta cases, but not in booster-vaccinated Omicron cases. In Omicron cases, three-dose aVE was 68% (18%, 88%) effective against pneumonia, while two-dose vaccination was insufficient for Omicron. E-values were calculated, and the E-values confirmed the robustness of our findings. Conclusions: In Delta cases, two-dose vaccination within 6 months reduced pneumonia, disease severity, and the duration of viral shedding. Booster vaccination provided a high level of protection against pneumonia with Omicron and should be prioritized.

/pdf/effectiveness-of-inactivated-covid-19-vaccines-against-covid-2c3gk4mf.pdf

Effectiveness of Inactivated COVID-19 Vaccines against COVID-19 Caused by the SARS-CoV-2 Delta and Omicron Variants: A Retrospective Cohort Study

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

B. Yu

Author Tools

Chat about Author

Papers

Inhibitory effects of antibiotic-induced gut microbiota depletion on acute itch behavior in mice

Effectiveness of Inactivated COVID-19 Vaccines against COVID-19 Caused by the SARS-CoV-2 Delta and Omicron Variants: A Retrospective Cohort Study