Trends in COVID-19 Vaccine Administration and Effectiveness Through October 2021

Prior infections and effectiveness of SARS-CoV-2 vaccine in test-negative studies: a systematic review and meta-analysis

Prior infection with SARS-CoV-2 can provide protection against infection and severe COVID-19. We aimed to determine the impact of preexisting immunity on vaccine effectiveness (VE) estimates. We systematically reviewed and meta-analyzed 66 test-negative design studies that examined VE against infection or severe disease (hospitalization, intensive care unit admission, or death) for primary vaccination series. Pooled VE among studies that included people with prior COVID-19 infection was lower against infection (77%; 95% CI, 72-81) and severe disease (86%; 95% CI, 83-89) compared with studies that excluded people with prior COVID-19 infection (pooled VE against infection: 87% [95% CI, 85-89]; pooled VE against severe disease: 93% [95% CI, 91-95]). There was a negative correlation between VE estimates against infection and severe disease, and the cumulative incidence of cases before the start of the study or incidence rates during the study period. We found clear empirical evidence that higher levels of preexisting immunity were associated with lower VE estimates. Prior infections should be treated as both a confounder and effect modificatory when the policies target the whole population or are stratified by infection history, respectively.

Recognising the heterogeneity of Indigenous Peoples during the COVID-19 pandemic: a scoping review across Canada, Australia, New Zealand and the USA

Objectives

The COVID-19 pandemic has had a disproportionate impact on the health of Indigenous Peoples in Canada, Australia, New Zealand and the USA, as reflected in the growing literature. However, Indigenous Peoples are often homogenised, with key differences often overlooked, failing to capture the complexity of issues and may lead to suboptimal public health policy-making. The objective of this review was to assess the extent to which the heterogeneity of the Indigenous Peoples in Canada, Australia, New Zealand and the USA has been reflected in COVID-19 research.

Design

This study took the form of a scoping review.

Data sources

Medline, Embase, CINAHL and Web of Science were searched for studies investigating COVID-19 pandemic outcomes among Indigenous Peoples in Canada, Australia, New Zealand and the USA. The search dates included January 2019 to January 2024.

Eligibility criteria

All citations yielded by this search were subjected to title and abstract screening, full-text review and data extraction. We included original, peer-reviewed research investigating COVID-19-related outcomes among Indigenous Peoples in Canada, Australia, New Zealand or the USA.

Data extraction and synthesis

Data extraction was conducted as an iterative process, reaching consensus between two of the study authors. All included studies were analysed through a combination of quantitative descriptive summary and qualitative thematic analysis.

Results

Of the 9795 citations found by the initial search, 428 citations were deemed eligible for inclusion. Of these citations: 72.9% compared Indigenous participants to non-Indigenous participants; 10.0% aggregated Indigenous and non-white participants; and 17.1% provided findings for Indigenous participants exclusively.

Conclusions

By overlooking the heterogeneity that exists among Indigenous Peoples in Canada, Australia, New Zealand and the USA, researchers and policy-makers run the risk of masking inequities and the unique needs of groups of Indigenous Peoples. This may lead to inefficient policy recommendations and unintentionally perpetuate health disparities during public health crises.

COVID-19 in pregnancy: prevalence, management, and outcomes in a single large health system

OBJECTIVE

This study assessed the prevalence of SARS-CoV-2 positivity in a cohort of pregnant patients served by a single health system. Treatments and outcomes are compared by maternal SARS-CoV-2 status and COVID-19 symptomatology.

METHODS

This was a retrospective cohort study of patients with delivery outcomes from March 2020-December 2021. SARS-CoV-2 positivity was defined by patients who had a positive test or COVID-19 diagnosis during pregnancy. Descriptive analysis compared demographics, medical management during pregnancy, and both perinatal and non-obstetric outcomes by SARS-CoV-2/COVID-19 status (negative, positive-asymptomatic, and positive-symptomatic).

RESULTS

Of 24,310 pregnancies, 94.6% were negative, 3.9% were positive-asymptomatic, and 1.5% were positive-symptomatic. Non-delivery hospitalizations were highest among positive-symptomatic patients (16.8%), followed by positive-asymptomatic patients (3.9%) and lastly negative patients (2.7%) (p < 0.001). Likewise, Intensive Care Unit (ICU) admissions during an antepartum or delivery admission were higher for positive-symptomatic patients (13.0%) compared to positive-asymptomatic patients or negative patients (0.7% and 0.5%, respectively, p < 0.001). The rate of preterm birth was significantly higher in positive-symptomatic patients compared to positive-asymptomatic and negative patients (15.7% vs. 9.5% and 9.8%, respectively, p = 0.002). There were no statistically significant differences in rates of miscarriage or intrauterine fetal demise. Maternal readmission, administration of corticosteroids for fetal lung maturity, birthweight, and neonatal intensive care unit (NICU) admission were significantly affected by SARS-CoV-2 status.

CONCLUSION

Pregnant patients testing positive for SARS-CoV-2 were mostly asymptomatic and identified during routine screening. Symptomatic patients were significantly more likely to require hospitalization and ICU admission with some increase in adverse perinatal outcomes.

COVID-19 Breakthrough Infections Among People With HIV: A Statewide Cohort Analysis

OBJECTIVES

This study aims to identify COVID-19 breakthrough infections among people with HIV (PWH) across different phases of the pandemic and explore whether differential immune dysfunctions are associated with breakthrough infections.

DESIGN AND METHODS

This retrospective population-based cohort study used data from an integrated electronic health record (EHR) database in South Carolina (SC). Breakthrough infection was defined as the first COVID-19 diagnosis documented in the state agency after the date an individual was fully vaccinated (ie, 2 doses of Pfizer/BNT162b2 or Moderna/mRNA-1273, or 1 dose of Janssen/Ad26.COV2.S) through June 14, 2022. We analyzed the risk and associated factors of the outcome using Cox proportional hazards models.

RESULTS

Among 7596 fully vaccinated PWH, the overall rate of breakthrough infections was 118.95 cases per 1000 person-years. When compared with the alpha-dominant period, the breakthrough infection rate was higher during both delta-dominant (HR: 1.50; 95% CI: 1.25 to 1.81) and omicron-dominant (HR: 2.86; 95% CI: 1.73 to 4.73) periods. Individuals who received a booster dose had a lower likelihood of breakthrough infections (HR: 0.19; 95% CI: 0.15 to 0.24). There was no association of breakthrough infections with degree of HIV viral suppression, but a higher CD4 count was significantly associated with fewer breakthroughs among PWH (>500 vs <200 cells/mm3: HR: 0.68; 95% CI: 0.49 to 0.94).

CONCLUSIONS

In our PWH population, the incidence of breakthrough infections was high (during both delta-dominant and omicron-dominant periods) and mainly associated with the absence of a booster dose in patients older than 50 years, with comorbidities and low CD4 count.

Global burden of vaccine-associated rheumatic diseases and their related vaccines, 1967-2023: A comprehensive analysis of the international pharmacovigilance database

Vaccine-associated rheumatic diseases are rare but one of the most feared adverse drug reactions (ADRs). However, this topic has been investigated less with large-scale data in the literature. With the rapid progress in the development and approval of vaccines during the pandemic, public concerns regarding their safety have been raised. To assess the global and regional burden, long-term trends, and potential risk factors of vaccines-associated six types of rheumatic diseases (ankylosing spondylitis [AS], polymyalgia rheumatica [PMR], rheumatoid arthritis [RA], Sjögren's syndrome, Systemic lupus erythematosus [SLE], Systemic scleroderma), this study conducted disproportionality analysis based on the reports from the World Health Organization International Pharmacovigilance Database documented between 1967 and 2023 (n for total reports = 131 255 418) across 156 countries and territories. We estimated the reporting odds ratio (ROR) and information component (IC) to determine the disproportionality signal for rheumatic diseases. Of 198 046 reports of all-cause rheumatic diseases, 14 703 reports of vaccine-associated rheumatic diseases were identified. While the reporting counts have gradually increased over time globally, we observed a dramatic increase in reporting counts after 2020, potentially due to a large portion of reports of COVID-19 mRNA vaccine-associated rheumatic diseases. The disproportionality signal for rheumatic diseases was most pronounced in HBV vaccines (ROR, 4.11; IC025, 1.90), followed by COVID-19 mRNA (ROR, 2.79; IC025, 1.25), anthrax (ROR, 2.52; IC025, 0.76), papillomavirus (ROR, 2.16; IC025, 0.95), encephalitis (ROR, 2.01; IC025, 0.58), typhoid (ROR, 1.91; IC025, 0.44), influenza (ROR, 1.49; IC025, 0.46), and HAV vaccines (ROR, 1.41; IC025, 0.20). From age- and sex-specific perspective, young females and old males are likely to have vaccine-associated rheumatic disease reports. Furthermore, overall vaccines showed a disproportionality signal for PMR (IC025, 3.13) and Sjögren's syndrome (IC025, 0.70), systemic scleroderma (IC025, 0.64), specifically while the COVID-19 mRNA vaccines are associated with all six types of diseases. Although multiple vaccines are associated with rheumatic disease reports, healthcare providers should be aware of the potential of autoimmune manifestations following vaccination, particularly the COVID-19 mRNA and HBV vaccines, and take into account for risk factors associated with these ADRs. Most ADRs exhibited an average time to onset of 11 days, underscoring the significance of monitoring and timely management by clinicians.

Effectiveness of BNT162b2 Vaccine for Preventing COVID-19-Related Hospitalizations: A Test-Negative Case-Control Study

It is important to understand real-world BNT162b2 COVID-19 vaccine effectiveness (VE), especially among racial and ethnic minority groups. We performed a test-negative case-control study to measure BNT162b2 COVID-19 VE in the prevention of COVID-19-associated acute respiratory illness (ARI) hospitalizations at two Atlanta hospitals from May 2021-January 2023 and adjusted for potential confounders by multivariate analysis. Among 5139 eligible adults with ARI, 2763 (53.8%) were enrolled, and 1571 (64.5%) were included in the BNT162b2 analysis. The median age was 58 years (IQR, 44-68), 889 (56.6%) were female, 1034 (65.8%) were African American, 359 (22.9%) were White, 56 (3.6%) were Hispanic ethnicity, 645 (41.1%) were SARS-CoV-2-positive, 412 (26.2%) were vaccinated with a primary series, and 273 (17.4%) had received ≥1 booster of BNT162b2. The overall adjusted VE of the BNT162b2 primary series was 58.5% (95% CI 46.0, 68.1), while the adjusted VE of ≥1 booster was 78.9% (95% CI 70.0, 85.1). The adjusted overall VE of primary series for African American/Black individuals was 64.0% (95% CI 49.9, 74.1) and 82.7% (95% CI 71.9, 89.4) in those who received ≥1 booster. When analysis was limited to the period of Omicron predominance, overall VE of the primary series decreased with widened confidence intervals (24.5%, 95% CI -4.5, 45.4%), while VE of ≥1 booster was maintained at 60.9% (95% CI 42.0, 73.6). BNT162b2 primary series and booster vaccination provided protection against COVID-19-associated ARI hospitalization among a predominantly African American population.

Vaccine Effectiveness Against SARS-CoV-2 Related Hospitalizations in People who had Experienced Homelessness or Incarceration - Findings from the Minnesota EHR Consortium

COVID-19 disproportionately affects people experiencing homelessness or incarceration. While homelessness or incarceration alone may not impact vaccine effectiveness, medical comorbidities along with social conditions associated with homelessness or incarceration may impact estimated vaccine effectiveness. COVID-19 vaccines reduce rates of hospitalization and death; vaccine effectiveness (VE) against severe outcomes in people experiencing homelessness or incarceration is unknown. We conducted a retrospective, observational cohort study evaluating COVID-19 vaccine VE against SARS-CoV-2 related hospitalization (positive SARS-CoV-2 molecular test same week or within 3 weeks prior to hospital admission) among patients who had experienced homelessness or incarceration. We utilized data from 8 health systems in the Minnesota Electronic Health Record Consortium linked to data from Minnesota's immunization information system, Homeless Management Information System, and Department of Corrections. We included patients 18 years and older with a history of experiencing homelessness or incarceration. VE and 95% Confidence Intervals (CI) against SARS-CoV-2 hospitalization were estimated for primary series and one booster dose from Cox proportional hazard models as 100*(1-Hazard Ratio) during August 26, 2021, through October 8, 2022 adjusting for patient age, sex, comorbid medical conditions, and race/ethnicity. We included 80,051 individuals who had experienced homelessness or incarceration. Adjusted VE was 52% (95% CI, 41-60%) among those 22 weeks or more since their primary series, 66% (95% CI, 53-75%) among those less than 22 weeks since their primary series, and 69% (95% CI: 60-76%) among those with one booster. VE estimates were consistently lower during the Omicron predominance period compared with the combined Omicron and Delta periods. Despite higher exposure risk, COVID-19 vaccines provided good effectiveness against SARS-CoV-2 related hospitalizations in persons who have experienced homelessness or incarceration.

COVID-19 breakthrough infections among people living with and without HIV: A statewide cohort analysis

OBJECTIVES

This study aims to characterize and compare COVID-19 breakthrough infections between people living with and without HIV across different phases of the pandemic.

METHODS

Using statewide HIV cohort data, the study population included adult residents in South Carolina (SC) (>18 years old) who were fully vaccinated between January 02, 2021 and April 14, 2022 when Alpha, Delta, and Omicron variants were circulating in SC. We used the Cox proportional hazard model to investigate the association between HIV infection and breakthrough infection, adjusting for relevant covariates.

RESULTS

Among 2,144,415 vaccinated individuals, 8,335 were people living with HIV (PLWH) and 2,136,080 were people without HIV (PWoH). After propensity score matching, HIV infection was not significantly associated with breakthrough infection rate. However, when comparing breakthrough infections among individuals without any booster dose, PLWH had a higher risk of breakthrough infections (adjusted Hazard Ration: 1.19; 95% confidence interval: 1.03-1.39). Compared to PWoH, PLWH with high levels of clusters of differentiation 4 (CD4) count or viral suppression were not associated with breakthrough infections.

CONCLUSIONS

Our findings do not support a broad conclusion that COVID-19 vaccine effectiveness is lower among PLWH, while we did find that PLWH had a higher risk of breakthrough infection compared to PWoH if they did not receive a booster dose.

Minnesota Data Sharing May Be Model For Near-Real-Time Tracking Of Drug Overdose Hospital And ED Trends

The drug overdose epidemic in the US necessitates detailed and timely data to inform public health responses. In this article we describe how an electronic health record (EHR) data-sharing collaboration across health systems in Minnesota that was developed in response to the COVID-19 pandemic was adapted to monitor trends in substance use-related hospital and emergency department (ED) visits. We found large increases in methamphetamine- and opioid-involved hospital and ED visits. Throughout the study period, Native American, Black, and multiple-race people experienced the highest rates of drug-involved hospital and ED visits. Monitoring drug-involved health care use through EHR data has the potential to help public health officials detect trends in near real time before mortality spikes and may also inform early intervention. The use of EHR data also allows for detailed monitoring of the impact of the drug overdose epidemic across racial and ethnic groups.

Vaccine efficacy against SARS-CoV-2 for Pfizer BioNTech, Moderna, and AstraZeneca vaccines: a systematic review

The purpose of this systematic review was to report on the vaccine efficacy (VE) of three SARS-CoV-2 vaccines approved by Health Canada: Pfizer BioNTech, Moderna, and AstraZeneca. Four databases were searched for primary publications on population-level VE. Ninety-two publications matched the inclusion criteria, and the extracted data were separated by vaccine type: mRNA vaccines (Pfizer and Moderna) and the AstraZeneca vaccine. The median VE for PCR-positive patients and various levels of clinical disease was determined for the first and second doses of both vaccine types against multiple SARS-CoV-2 variants. The median VE for PCR-positive infections against unidentified variants from an mRNA vaccine was 64.5 and 89%, respectively, after one or two doses. The median VE for PCR-positive infections against unidentified variants from the AstraZeneca vaccine was 53.4 and 69.6%, respectively, after one or two doses. The median VE for two doses of mRNA for asymptomatic, symptomatic, and severe infection against unidentified variants was 85.5, 93.2, and 92.2%, respectively. The median VE for two doses of AstraZeneca for asymptomatic, symptomatic, and severe infection against unidentified variants was 69.7, 71, and 90.2%, respectively. Vaccine efficacy numerically increased from the first to the second dose, increased from the first 2 weeks to the second 2 weeks post-vaccination for both doses, but decreased after 4 months from the second dose. Vaccine efficacy did not differ by person's age.

SARS-CoV-2 vaccine breakthrough infection in the older adults: a meta-analysis and systematic review

BACKGROUND

Corona Virus Disease 2019 (COVID-19) mRNA vaccine effectiveness (VE) has recently declined, and reports about COVID-19 breakthrough infection have increased. We aimed to conduct a meta-analysis on population-based studies of the prevalence and incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection amongst older adults worldwide.

METHODS

Studies from PubMed, Embase, Cochrane Library, and Web of Science were systematically screened to determine the prevalence and incidence of SARS-CoV-2 breakthrough infection in older adults from inception to November 2, 2022. Our meta-analysis included 30 studies, all published in English. Pooled estimates were calculated using a random-effect model through the inverse variance method. Publication bias was tested through funnel plots and Egger's regression test, and sensitivity analyses were performed to confirm the robustness of the results. This research was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Thirty publications were included in this meta-analysis (17 on prevalence, 17 on incidence, and 4 on both). The pooled prevalence of COVID-19 breakthrough infection among older adults was 7.7 per 1,000 persons (95% confidence interval [95%CI] 4.0-15.0). At the same time, the pooled incidence was 29.1 per 1000 person-years (95%CI 15.2-55.7).

CONCLUSIONS

This meta-analysis provides estimates of prevalence and incidence in older adults. We concluded that the prevalence and incidence of SARS-CoV-19 breakthrough infection in older people was low. The prevalence and incidence of breakthrough infection admitted to hospital, severe-critical, and deathly was significantly lower. Otherwise, there was considerable heterogeneity among estimates in this study, which should be considered when interpreting the results.

Using wastewater to overcome health disparities among rural residents

The SARS-CoV-2 pandemic highlighted the need for novel tools to promote health equity. There has been a historical legacy around the location and allocation of public facilities (such as health care) focused on efficiency, which is not attainable in rural, low-density, United States areas. Differences in the spread of the disease and outcomes of infections have been observed between urban and rural populations throughout the COVID-19 pandemic. The purpose of this article was to review rural health disparities related to the SARS-CoV-2 pandemic while using evidence to support wastewater surveillance as a potentially innovative tool to address these disparities more widely. The successful implementation of wastewater surveillance in resource-limited settings in South Africa demonstrates the ability to monitor disease in underserved areas. A better surveillance model of disease detection among rural residents will overcome issues around the interactions of a disease and social determinants of health. Wastewater surveillance can be used to promote health equity, particularly in rural and resource-limited areas, and has the potential to identify future global outbreaks of endemic and pandemic viruses.

Relationships Between Social Vulnerability and Coronavirus Disease 2019 Vaccination Coverage and Vaccine Effectiveness

BACKGROUND

Coronavirus disease 2019 (COVID-19) vaccination coverage remains lower in communities with higher social vulnerability. Factors such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure risk and access to healthcare are often correlated with social vulnerability and may therefore contribute to a relationship between vulnerability and observed vaccine effectiveness (VE). Understanding whether these factors impact VE could contribute to our understanding of real-world VE.

METHODS

We used electronic health record data from 7 health systems to assess vaccination coverage among patients with medically attended COVID-19-like illness. We then used a test-negative design to assess VE for 2- and 3-dose messenger RNA (mRNA) adult (≥18 years) vaccine recipients across Social Vulnerability Index (SVI) quartiles. SVI rankings were determined by geocoding patient addresses to census tracts; rankings were grouped into quartiles for analysis.

RESULTS

In July 2021, primary series vaccination coverage was higher in the least vulnerable quartile than in the most vulnerable quartile (56% vs 36%, respectively). In February 2022, booster dose coverage among persons who had completed a primary series was higher in the least vulnerable quartile than in the most vulnerable quartile (43% vs 30%). VE among 2-dose and 3-dose recipients during the Delta and Omicron BA.1 periods of predominance was similar across SVI quartiles.

CONCLUSIONS

COVID-19 vaccination coverage varied substantially by SVI. Differences in VE estimates by SVI were minimal across groups after adjusting for baseline patient factors. However, lower vaccination coverage among more socially vulnerable groups means that the burden of illness is still disproportionately borne by the most socially vulnerable populations.

Impact of COVID-19 pandemic on surgical outcomes after hepatopancreatobiliary (HPB) surgery

COVID-19 pandemic has disrupted healthcare systems worldwide, causing the postponement or cancellation of millions of elective surgeries. It is essential for hepatopancreatobiliary (HPB) surgeons to well understand the perioperative risk and management of HPB surgery during the COVID-19 pandemic, including the impact of preoperative COVID-19 infection and timing of surgery, the impact of COVID-19 infection on postoperative mortality, the postoperative pulmonary complications in patients with perioperative COVID-19 infection, and the postoperative complications without pulmonary involvement. Perioperative COVID-19 infection increases the risk of postoperative mortality and pulmonary complications in patients undergoing abdominal surgery. Furthermore, in some regions, the COVID-19 vaccine's availability is still limited, leading to an increase in the number of cases and potential medical collapse, which could hinder the improvement of HPB postoperative mortality rates. The timing of surgery for COVID-19 positive patients should be carefully considered, balancing the potential risks of delay with the risks of surgery during the infection.

Effectiveness of COVID-19 mRNA Vaccines in Preventing COVID-19-Associated Outpatient Visits and Hospitalizations Among American Indian and Alaska Native Persons, January-November 2021: A Test-Negative Case-Control Analysis Using Surveillance Data

Background

Despite the disproportionate morbidity and mortality experienced by American Indian and Alaska Native (AI/AN) persons during the coronavirus disease 2019 (COVID-19) pandemic, few studies have reported vaccine effectiveness (VE) estimates among these communities.

Methods

We conducted a test-negative case-control analysis among AI/AN persons aged ≥12 years presenting for care from January 1, 2021, through November 30, 2021, to evaluate the effectiveness of mRNA COVID-19 vaccines against COVID-19-associated outpatient visits and hospitalizations. Cases and controls were patients with ≥1 symptom consistent with COVID-19-like illness; cases were defined as those test-positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and controls were defined as those test-negative for SARS-CoV-2. We used unconditional multivariable logistic regression to estimate VE, defined as 1 minus the adjusted odds ratio for vaccination among cases vs controls.

Results

The analysis included 207 cases and 267 test-negative controls. Forty-four percent of cases and 78% of controls received 2 doses of either BNT162b2 or mRNA-1273 vaccine. VE point estimates for 2 doses of mRNA vaccine were higher for hospitalized participants (94.6%; 95% CI, 88.0-97.6) than outpatient participants (86.5%; 95% CI, 63.0-95.0), but confidence intervals overlapped.

Conclusions

Among AI/AN persons, mRNA COVID-19 vaccines were highly effective in preventing COVID-associated outpatient visits and hospitalizations. Maintaining high vaccine coverage, including booster doses, will reduce the burden of disease in this population.

The impact of vaccination and outpatient treatment on the economic burden of Covid-19 in the United States omicron era: a systematic literature review

AIMS

To identify and synthesize evidence regarding how coronavirus disease 2019 (COVID-19) interventions, including vaccines and outpatient treatments, have impacted healthcare resource use (HCRU) and costs in the United States (US) during the Omicron era.

MATERIALS AND METHODS

A systematic literature review (SLR) was performed to identify articles published between 1 January 2021 and 10 March 2023 that assessed the impact of vaccination and outpatient treatment on costs and HCRU outcomes associated with COVID-19. Screening was performed by two independent researchers using predefined inclusion/exclusion criteria.

RESULTS

Fifty-eight unique studies were included in the SLR, of which all reported HCRU outcomes, and one reported costs. Overall, there was a significant reduction in the risk of COVID-19-related hospitalization for patients who received an original monovalent primary series vaccine plus booster dose vs. no vaccination. Moreover, receipt of a booster vaccine was associated with a lower risk of hospitalization vs. primary series vaccination. Evidence also indicated a significantly reduced risk of hospitalizations among recipients of nirmatrelvir/ritonavir (NMV/r), remdesivir, sotrovimab, and molnupiravir compared to non-recipients. Treated and/or vaccinated patients also experienced reductions in intensive care unit (ICU) admissions, length of stay, and emergency department (ED)/urgent care clinic encounters.

LIMITATIONS

The identified studies may not represent unique patient populations as many utilized the same regional/national data sources. Synthesis of the evidence was also limited by differences in populations, outcome definitions, and varying duration of follow-up across studies. Additionally, significant gaps, including HCRU associated with long COVID and various high-risk populations and cost data, were observed.

CONCLUSIONS

Despite evidence gaps, findings from the SLR highlight the significant positive impact that vaccination and outpatient treatment have had on HCRU in the US, including periods of Omicron predominance. Continued research is needed to inform clinical and policy decision-making in the US as COVID-19 continues to evolve as an endemic disease.