Effectiveness of Covid-19 vaccines against symptomatic and asymptomatic SARS-CoV-2 infections in an urgent care setting

Rane, Madhura S.; Robertson, McKaylee; Kulkarni, Sarah; Frogel, Daniel; Gainus, Chris; Nash, Denis

doi:10.1016/j.vaccine.2022.12.039

Cited by 3 publications

(2 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This could be a form of selection bias within the sample and seems to be supported by a much smaller proportion of outpatients who were in the longitudinal study. COVID-19 vaccines have been shown to be effective at preventing symptomatic SARS-CoV-2 infections and long COVD (29,30). In this study, however, vaccinated patients failed to show significant protective association between COVID vaccination and long COVID.…”

Section: Discussioncontrasting

confidence: 57%

See 1 more Smart Citation

Clinical Characteristics and Factors Associated with Long COVID in Zambia, August 2020 to January 2023: A Mixed Methods Design

Malambo,

Chanda,

Besa

et al. 2024

Preprint

View full text Add to dashboard Cite

BackgroundSeveral seroprevalence studies in Africa documented the extent of spread of SARS-CoV-2, yet there is limited data on signs, symptoms and conditions that continue or develop after acute COVID-19 infection (long COVID). We sought to examine patient characteristics at post-acute COVID-19 (PAC-19) clinics in Zambia and assess factors associated with long COVID at first visit to a PAC-19 clinic and longitudinally among a cohort of patients.MethodsLong COVID was defined, initially in the Zambia PAC-19 clinical guidelines, as new, relapsing or persistent symptoms lasting >4 weeks after an initial SARS-CoV-2 infection. Severe illness was defined as COVID-19 episode that required supplemental oxygen therapy, intensive care unit stay or treatment with steroids/remdesivir. We fitted logistic regression models with cross-sectional and longitudinal data and considered statistical significance at p<0.05.ResultsIn total, 1,359 patients attended PAC-19 clinics and had data abstracted from Aug-2020 to Jan-2023; 548 (40.3%) patients with ≥2 visits were included in the longitudinal analysis. Patients’ median age was 53 (interquartile range [IQR]: 41-63) years, 919 (67.6%) were hospitalized for acute COVID-19, and of whom 686 (74.6%) had severe illness. Patients with hospital length of stay ≥15 days (adjusted odds ratio [aOR]: 5.50; 95% confidence interval [95% CI]: 3.06-10.3), severe illness (aOR: 3.23; 95% CI: 1.68-6.75), and comorbidities (aOR:1.51; 95% CI: 1.04-2.22) had significantly higher odds of long COVID. Longitudinally, long COVID prevalence significantly (p<0.001) declined from 75.4% at the first PAC-19 visit to 26.0% by the fifth visit. The median follow-up time was 7 (IQR: 4-12) weeks.ConclusionLong COVID symptoms were common among patient presenting for care in PAC-19 clinics in Zambia, but most recovered within ∼2 months. Despite potentially substantial morbidity due to long COVID, few patients overall with COVID-19 attended a PAC-19 clinic. Scaling up PAC-19 services and integrating into routine clinical care could improve access by patients.

show abstract

Section: Discussioncontrasting

confidence: 57%

“…COVID-19 vaccines have been shown to be effective at preventing symptomatic SARS-CoV-2 infections and long COVD (29, 30). In this study, however, vaccinated patients failed to show significant protective association between COVID vaccination and long COVID.…”

Section: Discussionmentioning

confidence: 99%

Clinical Characteristics and Factors Associated with Long COVID in Zambia, August 2020 to January 2023: A Mixed Methods Design

Malambo,

Chanda,

Besa

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

Clinical characteristics and factors associated with long COVID among post-acute COVID-19 clinic patients in Zambia, August 2020 to January 2023: A cross-sectional and longitudinal study design

Malambo,

Chanda,

Besa

et al. 2024

PLoS ONE

View full text Add to dashboard Cite

Introduction A number of seroprevalence studies in Zambia document the extent of spread of acute SARS-CoV-2 infection, yet knowledge gaps still exist on symptoms and conditions that continue or develop after acute COVID-19 (long COVID). This is an important gap given the estimated prevalence of long COVID in other African countries. We assessed factors associated with long COVID at the initial visit to a post-acute COVID-19 (PAC-19) clinic and longitudinally among a cohort of patients with ≥2 review visits. Methods We implemented a cross-sectional and longitudinal analysis of PAC-19 clinic patients from Aug-2020 to Jan-2023. The study outcome was long COVID; defined as the presence of new, relapsing, or persistent COVID-19 symptoms that interfere with the ability to function at home or work. Explanatory variables were demographic and clinical characteristics of patients which included sex, age group, presence of new onset medical conditions, presence of pre-existing comorbidities, vaccination status and acute COVID-19 episode details. We fitted logistic and mixed effects regression models to assess for associated factors and considered statistical significance at p<0.05. Results Out of a total 1,359 PAC-19 clinic patients in the cross-sectional analysis, 548 (40.3%) patients with ≥2 PAC-19 clinic visits were in the longitudinal analysis. Patients’ median age was 53 (interquartile range [IQR]: 41–63) years, 919 (67.6%) were hospitalized for acute COVID-19, and of whom 686 (74.6%) had severe acute COVID-19. Overall, 377 (27.7%) PAC-19 clinic patients had long COVID. Patients with hospital length of stay ≥15 days (adjusted odds ratio [aOR]: 5.37; 95% confidence interval [95% CI]: 2.99–10.0), severe acute COVID-19 (aOR: 3.22; 95% CI: 1.68–6.73), and comorbidities (aOR:1.50; 95% CI: 1.02–2.21) had significantly higher chance of long COVID. Longitudinally, long COVID prevalence significantly (p<0.001) declined from 75.4% at the initial PAC-19 visit to 26.0% by the final visit. The median follow-up time was 7 (IQR: 4–12) weeks. Conclusion Factors associated with long COVID in Zambia were consistent both cross-sectionally at the initial visit to PAC-19 clinics and longitudinally across subsequent review visits. This highlights the importance of ongoing monitoring and tailored interventions for patients with comorbidities and severe COVID-19 to mitigate the long-term impacts of COVID-19.

show abstract

Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review

Bolormaa,

Shim,

Choi

et al. 2024

PHRP

View full text Add to dashboard Cite

Objectives: This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.Methods: A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.Results: We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1−odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.Conclusion: Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.

show abstract

Effectiveness of Covid-19 vaccines against symptomatic and asymptomatic SARS-CoV-2 infections in an urgent care setting

Cited by 3 publications

References 52 publications

Clinical Characteristics and Factors Associated with Long COVID in Zambia, August 2020 to January 2023: A Mixed Methods Design

Clinical Characteristics and Factors Associated with Long COVID in Zambia, August 2020 to January 2023: A Mixed Methods Design

Clinical characteristics and factors associated with long COVID among post-acute COVID-19 clinic patients in Zambia, August 2020 to January 2023: A cross-sectional and longitudinal study design

Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review

Contact Info

Product

Resources

About