Molnupiravir and risk of hospital admission or death in adults with covid-19: emulation of a randomized target trial using electronic health records

Perceived Risk for Severe COVID-19 and Oral Antiviral Use Among Antiviral-Eligible US Adults

INTRODUCTION

Oral antiviral medications are important tools for preventing severe COVID-19 outcomes. However, their uptake remains low for reasons that are not entirely understood. Our study aimed to assess the association between perceived risk for severe COVID-19 outcomes and oral antiviral use among those who were eligible for treatment based on Centers for Disease Control and Prevention (CDC) guidelines.

METHODS

We surveyed 4034 non-institutionalized US adults in April 2023, and report findings from 934 antiviral-eligible participants with at least one confirmed SARS-CoV-2 infection since December 1, 2021 and no current long COVID symptoms. Survey weights were used to yield nationally representative estimates. The primary exposure of interest was whether participants perceived themselves to be "at high risk for severe COVID-19." The primary outcome was use of a COVID-19 oral antiviral within 5 days of suspected SARS-CoV-2 infection.

RESULTS

Only 18.5% of antiviral-eligible adults considered themselves to be at high risk for severe COVID-19 and 16.8% and 15.9% took oral antivirals at any time or within 5 days of SARS-CoV-2 infection, respectively. In contrast, 79.8% were aware of antiviral treatments for COVID-19. Perceived high-risk status was associated with being more likely to be aware (adjusted prevalence ratio [aPR]: 1.11 [95% confidence interval (CI) 1.03-1.20]), to be prescribed (aPR 1.47 [95% CI 1.08-2.01]), and to take oral antivirals at any time (aPR 1.61 [95% CI 1.16-2.24]) or within 5 days of infection (aPR 1.72 [95% CI 1.23-2.40]).

CONCLUSIONS

Despite widespread awareness of the availability of COVID-19 oral antivirals, more than 80% of eligible US adults did not receive them. Our findings suggest that differences between perceived and actual risk for severe COVID-19 (based on current CDC guidelines) may partially explain this low uptake.

Pathogenic mechanisms of cardiovascular damage in COVID-19

BACKGROUND

COVID-19 is a new infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2). Since the outbreak in December 2019, it has caused an unprecedented world pandemic, leading to a global human health crisis. Although SARS CoV-2 mainly affects the lungs, causing interstitial pneumonia and severe acute respiratory distress syndrome, a number of patients often have extensive clinical manifestations, such as gastrointestinal symptoms, cardiovascular damage and renal dysfunction.

PURPOSE

This review article discusses the pathogenic mechanisms of cardiovascular damage in COVID-19 patients and provides some useful suggestions for future clinical diagnosis, treatment and prevention.

METHODS

An English-language literature search was conducted in PubMed and Web of Science databases up to 12th April, 2024 for the terms "COVID-19", "SARS CoV-2", "cardiovascular damage", "myocardial injury", "myocarditis", "hypertension", "arrhythmia", "heart failure" and "coronary heart disease", especially update articles in 2023 and 2024. Salient medical literatures regarding the cardiovascular damage of COVID-19 were selected, extracted and synthesized.

RESULTS

The most common cardiovascular damage was myocarditis and pericarditis, hypertension, arrhythmia, myocardial injury and heart failure, coronary heart disease, stress cardiomyopathy, ischemic stroke, blood coagulation abnormalities, and dyslipidemia. Two important pathogenic mechanisms of the cardiovascular damage may be direct viral cytotoxicity as well as indirect hyperimmune responses of the body to SARS CoV-2 infection.

CONCLUSIONS

Cardiovascular damage in COVID-19 patients is common and portends a worse prognosis. Although the underlying pathophysiological mechanisms of cardiovascular damage related to COVID-19 are not completely clear, two important pathogenic mechanisms of cardiovascular damage may be the direct damage of the SARSCoV-2 infection and the indirect hyperimmune responses.

COVID-19 therapeutics

SUMMARYSince the emergence of COVID-19 in 2020, an unprecedented range of therapeutic options has been studied and deployed. Healthcare providers have multiple treatment approaches to choose from, but efficacy of those approaches often remains controversial or compromised by viral evolution. Uncertainties still persist regarding the best therapies for high-risk patients, and the drug pipeline is suffering fatigue and shortage of funding. In this article, we review the antiviral activity, mechanism of action, pharmacokinetics, and safety of COVID-19 antiviral therapies. Additionally, we summarize the evidence from randomized controlled trials on efficacy and safety of the various COVID-19 antivirals and discuss unmet needs which should be addressed.

Molnupiravir Use Among Patients with COVID-19 in Real-World Settings: A Systematic Literature Review

INTRODUCTION

Molnupiravir (MOV) is an oral antiviral for the treatment of individuals with mild-to-moderate COVID-19 and at high risk of progression to severe disease. Our objective was to conduct a systematic literature review (SLR) of evidence on the effectiveness of MOV in reducing the risk of severe COVID-19 outcomes in real-world outpatient settings.

METHODS

The SLR was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines and using pre-determined population, intervention, comparison, outcome, time, and study design inclusion criteria. Eligible studies were published between January 1, 2021, and March 10, 2023, and evaluated the real-world effectiveness of MOV compared to no treatment in reducing the risk of severe COVID-19 outcomes among outpatients ≥ 18 years of age with a laboratory-confirmed diagnosis of SARS-CoV-2 infection.

RESULTS

Nine studies from five countries were included in the review. The size of the MOV-treated group ranged from 359 to 7818 individuals. Omicron variants of SARS-CoV-2 were dominant in all study periods. Most studies noted differences in the baseline characteristics of the MOV-treated and untreated control groups, with the treated groups generally being older and with more comorbidities. Eight studies reported that treatment with MOV was associated with a significantly reduced risk of at least one severe COVID-19 outcome in at least one age group, with greater benefits consistently observed among older age groups.

CONCLUSIONS

In this SLR study, treatment with MOV was effective in reducing the risk of severe outcomes from COVID-19 caused by Omicron variants, especially for older individuals. Differences in the ages and baseline comorbidities of the MOV-treated and control groups may have led to underestimation of the effectiveness of MOV in many observational studies. Real-world studies published to date thus provide additional evidence supporting the continued benefits of MOV in non-hospitalized adults with COVID-19.

Effectiveness of nirmatrelvir/ritonavir and molnupiravir in non-hospitalized adults with COVID-19: systematic review and meta-analysis of observational studies

OBJECTIVE

To determine the effectiveness of nirmatrelvir/ritonavir and molnupiravir among vaccinated and unvaccinated non-hospitalized adults with COVID-19.

METHODS

Observational studies of nirmatrelvir/ritonavir or molnupiravir compared to no antiviral drug treatment for COVID-19 in non-hospitalized adults with data on vaccination status were included. We searched MEDLINE, EMBASE, Scopus, Web of Science, WHO COVID-19 Research Database and medRxiv for reports published between 1 January 2022 and 8 November 2023. The primary outcome was a composite of hospitalization or mortality up to 35 days after COVID-19 diagnosis. Risk of bias was assessed with ROBINS-I. Risk ratios (RR), hazard ratios (HR) and risk differences (RD) were separately estimated using random-effects models.

RESULTS

We included 30 cohort studies on adults treated with nirmatrelvir/ritonavir (n = 462 279) and molnupiravir (n = 48 008). Nirmatrelvir/ritonavir probably reduced the composite outcome (RR 0.62, 95%CI 0.55-0.70; I2 = 0%; moderate certainty) with no evidence of effect modification by vaccination status (RR Psubgroup = 0.47). In five studies, RD estimates against the composite outcome for nirmatrelvir/ritonavir were 1.21% (95%CI 0.57% to 1.84%) in vaccinated and 1.72% (95%CI 0.59% to 2.85%) in unvaccinated subgroups.Molnupiravir may slightly reduce the composite outcome (RR 0.75, 95%CI 0.67-0.85; I2 = 32%; low certainty). Evidence of effect modification by vaccination status was inconsistent among studies reporting different effect measures (RR Psubgroup = 0.78; HR Psubgroup = 0.08). In two studies, RD against the composite outcome for molnupiravir were -0.01% (95%CI -1.13% to 1.10%) in vaccinated and 1.73% (95%CI -2.08% to 5.53%) in unvaccinated subgroups.

CONCLUSIONS

Among cohort studies of non-hospitalized adults with COVID-19, nirmatrelvir/ritonavir is effective against the composite outcome of severe COVID-19 independent of vaccination status. Further research and a reassessment of molnupiravir use among vaccinated adults are warranted.

REGISTRATION

PROSPERO CRD42023429232.

Efficacy of late-onset antiviral treatment in immune-compromised hosts with persistent SARS-CoV-2 infection

The immunocompromised are at high risk of prolonged SARS-CoV-2 infection and progression to severe COVID-19. However, efficacy of late-onset direct-acting antiviral (DAA) therapy with therapeutics in clinical use and experimental drugs to mitigate persistent viral replication is unclear. In this study, we employed an immunocompromised mouse model, which supports prolonged replication of SARS-CoV-2 to explore late-onset treatment options. Tandem immuno-depletion of CD4 + and CD8 + T cells in C57BL/6 mice followed by infection with SARS-CoV-2 variant of concern (VOC) beta B.1.351 resulted in prolonged infection with virus replication for five weeks after inoculation. Early-onset treatment with nirmatrelvir/ritonavir (paxlovid) or molnupiravir was only moderately efficacious, whereas the experimental therapeutic 4'-fluorourdine (4'-FlU, EIDD-2749) significantly reduced virus load in upper and lower respiratory compartments four days post infection (dpi). All antivirals significantly lowered virus burden in a 7-day treatment regimen initiated 14 dpi, but paxlovid-treated animals experienced rebound virus replication in the upper respiratory tract seven days after treatment end. Viral RNA was detectable 28 dpi in paxlovid-treated animals, albeit not in the molnupiravir or 4'-FlU groups, when treatment was initiated 14 dpi and continued for 14 days. Low-level virus replication continued 35 dpi in animals receiving vehicle but had ceased in all treatment groups. These data indicate that late-onset DAA therapy significantly shortens the duration of persistent virus replication in an immunocompromised host, which may have implications for clinical use of antiviral therapeutics to alleviate the risk of progression to severe disease in highly vulnerable patients.

Importance

Four years after the onset of the global COVID-19 pandemic, the immunocompromised are at greatest risk of developing life-threatening severe disease. However, specific treatment plans for this most vulnerable patient group have not yet been developed. Employing a CD4 + and CD8 + T cell-depleted immunocompromised mouse model of SARS-CoV-2 infection, we explored therapeutic options of persistent infections with standard-of-care paxlovid, molnupiravir, and the experimental therapeutic 4'-FlU. Late-onset treatment initiated 14 days after infection was efficacious, but only 4'-FlU was rapidly sterilizing. No treatment-experienced viral variants with reduced susceptibility to the drugs emerged, albeit virus replication rebounded in animals of the paxlovid group after treatment end. This study supports the use of direct-acting antivirals for late-onset management of persistent SARS-CoV-2 infection in immunocompromised hosts. However, treatment courses likely require to be extended for maximal therapeutic benefit, calling for appropriately powered clinical trials to meet the specific needs of this patient group.

Making causal inferences from transactional data: A narrative review of opportunities and challenges when implementing the target trial framework

The target trial framework has emerged as a powerful tool for addressing causal questions in clinical practice and in public health. In the healthcare sector, where decision-making is increasingly data-driven, transactional databases, such as electronic health records (EHR) and insurance claims, present an untapped potential for answering complex causal questions. This narrative review explores the potential of the integration of the target trial framework with real-world data to enhance healthcare decision-making processes. We outline essential elements of the target trial framework, and identify pertinent challenges in data quality, privacy concerns, and methodological limitations, proposing solutions to overcome these obstacles and optimize the framework's application.

Nirmatrelvir/ritonavir use in pregnant women with SARS-CoV-2 Omicron infection: a target trial emulation

To date, there is a lack of randomized trial data examining the use of the antiviral nirmatrelvir/ritonavir in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pregnant persons. This target trial emulation study aimed to address this gap by evaluating the use of nirmatrelvir/ritonavir in nonhospitalized pregnant women with symptomatic SARS-CoV-2 Omicron variant infection. Among patients diagnosed between 16 March 2022 and 5 February 2023, exposure was defined as outpatient nirmatrelvir/ritonavir treatment within 5 days of symptom onset or coronavirus disease 2019 (COVID-19) diagnosis. Primary outcomes were maternal morbidity and mortality index (MMMI), all-cause maternal death and COVID-19-related hospitalization, while secondary outcomes were individual components of MMMI, preterm birth, stillbirth, neonatal death and cesarean section. One-to-ten propensity-score matching was conducted between nirmatrelvir/ritonavir users and nonusers, followed by cloning, censoring and weighting. Overall, 211 pregnant women on nirmatrelvir/ritonavir and 1,998 nonusers were included. Nirmatrelvir/ritonavir treatment was associated with reduced 28-day MMMI risk (absolute risk reduction (ARR) = 1.47%, 95% confidence interval (CI) = 0.21-2.34%) but not 28-days COVID-19-related hospitalization (ARR = -0.09%, 95% CI = -1.08% to 0.71%). Nirmatrelvir/ritonavir treatment was also associated with reduced risks of cesarean section (ARR = 1.58%, 95% CI = 0.85-2.39%) and preterm birth (ARR = 2.70%, 95% CI = 0.98-5.31%). No events of maternal or neonatal death or stillbirth were recorded. The findings suggest that nirmatrelvir/ritonavir is an effective treatment in symptomatic pregnant women with SARS-CoV-2 Omicron variant infection.

Safety and Effectiveness of Molnupiravir in Japanese Patients with COVID-19: Final Report of Post-marketing Surveillance in Japan

INTRODUCTION

Molnupiravir is an orally available prodrug of N-hydroxycytidine that received special approval for emergency treatment of coronavirus disease 2019 (COVID-19) in Japan in December 2021 and full approval in April 2023. To assess the real-world safety and effectiveness of molnupiravir in Japanese patients with COVID-19, we conducted nationwide post-marketing surveillance to collect data at registered institutions in Japan.

METHODS

The surveillance data were collected from December 27, 2021, to May 2, 2023. All reported adverse events were collected for safety analysis. Adverse drug reactions (ADRs) were assessed by the treating physicians. Effectiveness was assessed by the composite of hospitalization or all-cause death in outpatients and the composite of oxygen/mechanical ventilation initiation or all-cause death in inpatients. The observation period was from molnupiravir initiation through day 29.

RESULTS

Of 3214 patients enrolled in the survey, 3179 were analyzed for safety. At baseline, 52.31% (1663/3179) of patients were male, the median (range) age was 69.0 (18-107) years, 82.38% (2619/3179) received COVID-19 vaccines, and 95.72% (3043/3179) had risk factors for severe COVID-19 illness. COVID-19 severity at baseline was mild in 86.44% (2748/3179) and moderate I in 10.22% (325/3179). A total of 205 ADRs occurred in 5.50% (175/3179) of patients; ADRs that occurred in > 0.5% of patients were diarrhea (1.86% [59/3179]) and rash (0.69% [22/3179]). Seven serious ADRs were reported in seven patients. In the effectiveness analysis population, the incidence of all-cause death through day 29 was 1.14% (34/2988), and the incidence of death through day 29 related to COVID-19 was 0.40% (12/2988). The cumulative incidence of the composite endpoint was 2.34% (47/2006) in outpatients and 4.60% (38/826) in inpatients.

CONCLUSIONS

This large-scale survey showed that molnupiravir was safe and effective in real-world settings in highly vaccinated Japanese patients with COVID-19, including older patients and those with comorbidities.

Virologic Outcomes with Molnupiravir in Non-hospitalized Adult Patients with COVID-19 from the Randomized, Placebo-Controlled MOVe-OUT Trial

INTRODUCTION

The randomized, placebo-controlled, double-blind MOVe-OUT trial demonstrated molnupiravir (800 mg every 12 h for 5 days) as safe and effective for outpatient treatment of mild-to-moderate COVID-19, significantly reducing the risk of hospitalization/death in high-risk adults. At the time of that report, virologic assessments from the trial were partially incomplete as a result of their time-intensive nature. Here we present final results from all prespecified virology endpoints in MOVe-OUT based on the full trial dataset.

METHODS

Nasopharyngeal swabs were collected at baseline (day 1, prior to first dose) and days 3, 5 (end-of-treatment visit), 10, 15, and 29. From these samples, change from baseline in SARS-CoV-2 RNA titers (determined by quantitative PCR), detection of infectious SARS-CoV-2 (by plaque assay), and SARS-CoV-2 viral error induction (determined by whole genome next-generation sequencing) were assessed as exploratory endpoints.

RESULTS

Molnupiravir was associated with greater mean reductions from baseline in SARS-CoV-2 RNA than placebo (including 50% relative reduction at end-of-treatment) through day 10. Among participants with infectious virus detected at baseline (n = 96 molnupiravir, n = 97 placebo) and evaluable post-baseline samples, no molnupiravir-treated participant had infectious SARS-CoV-2 by day 3, whereas infectious virus was recovered from 21% of placebo-arm participants on day 3 and 2% at end-of-treatment. Consistent with molnupiravir's mechanism of action, sequence analysis demonstrated that molnupiravir was associated with an increased number of low-frequency transition errors randomly distributed across the SARS-CoV-2 RNA genome compared with placebo (median 143.5 molnupiravir, 15 placebo), while transversion errors were infrequent overall (median 2 in both arms). Outcomes were consistent regardless of baseline SARS-CoV-2 clade, presence of SARS-CoV-2-specific immune response, or viral load.

CONCLUSIONS

A 5-day course of orally administered molnupiravir demonstrated a consistently greater virologic effect than placebo, including rapidly eliminating infectious SARS-CoV-2, in high-risk outpatients with mild-to-moderate COVID-19.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04575597.

Budget impact of oral nirmatrelvir/ritonavir in adults at high risk for progression to severe COVID-19 in the United States

BACKGROUND

Nirmatrelvir/ritonavir (NMV/r) is indicated for the treatment of mild-to-moderate COVID-19 in adults who are at high risk for progression to severe COVID-19. NMV/r has also been authorized for emergency use by the US Food and Drug Administration for the treatment of mild-to-moderate COVID-19 in pediatric patients (aged 226512 years and weighing at least 40 kg) who are at high risk for progression to severe COVID-19. Understanding the budget impact of introducing NMV/r for the treatment of adults with COVID-19 is of key interest to US payers.

OBJECTIVE

To estimate the annual budget impact of introducing NMV/r in a US commercial health plan setting in the current Omicron COVID-19 era.

METHODS

A budget impact model was developed to assess the impact of NMV/r on health care costs in a hypothetical 1-million-member commercial health insurance plan over a 1-year period in the US population; clinical and cost inputs were derived from published literature with a focus on studies in the recent COVID-19 era that included vaccinated population and predominance of the Omicron variant. In the base-case analysis, it was assumed the only effect of NMV/r was a reduction in incidence (not severity) of hospitalization or death; its potential effect on post-COVID conditions was assessed in a scenario analysis. Outcomes included the number of hospitalizations, total cost, per patient per year (PPPY) costs, and per member per month (PMPM) costs. Sensitivity and scenario analyses were conducted to assess uncertainty around key model inputs.

RESULTS

An estimated 29,999 adults were eligible and sought treatment with oral antiviral for COVID-19 over 1 year. The availability of NMV/r was estimated to reduce the number of hospitalizations by 647 with a total budget impact of $2,733,745, $91 PPPY, and $0.23 PMPM. NMV/r was cost saving when including post-COVID conditions with a -$1,510,780 total budget impact, a PPPY cost of -$50, and a PMPM cost of -$0.13. Sensitivity analyses indicated results were most sensitive to the risk of hospitalization under supportive care, risk of hospitalization with NMV/r treatment and cost of NMV/r.

CONCLUSIONS

Treatment with NMV/r in the current COVID-19 era is estimated to result in substantial cost offsets because of reductions in hospitalization and modest budget impact to potential overall cost savings.

Effectiveness of Molnupiravir Treatment in Patients with COVID-19 in Korea: A Propensity Score Matched Study

BACKGROUND

The MOVe-OUT (efficacy and safety of molnupiravir [MK-4482] in non-hospitalized adult participants with COVID-19 [MK-4482-002]) trial reported that the administration of molnupiravir in unvaccinated patients with coronavirus disease 2019 (COVID-19) before the Omicron epidemic showed a preventive effect of 31% against hospitalization and death. However, studies on the preventive effect of molnupiravir against progression to severe disease and death in patients with COVID-19 during the Omicron epidemic are limited. This study aimed to evaluate the preventive effect of molnupiravir against severe/critical illness or death and death in Korean patients with COVID-19 who were vaccinated mostly during the Omicron epidemic.

MATERIALS AND METHODS

This study used large-scale retrospective cohort data to select patients with COVID-19 who were either treated or not treated with molnupiravir, between August 2022 and March 2023, at a ratio of 1 : 4 using the propensity score matching method. In total, 762,768 patients comprised the non- administered group, and 190,692 patients comprised the molnupiravir-administered group. The preventive effect of molnupiravir against severe/critical illness or death and death was analyzed using logistic regression analysis.

RESULTS

The preventive effect of molnupiravir against severe/critical illness or death and death, represented by the odds ratio (OR) and 95% confidence interval (CI), in the molnupiravir-administered and non-administered group was (OR: 0.714; CI: 0.667 - 0.764) and (OR: 0.749; CI: 0.682 - 0.823), respectively. As age increased, the preventive effect against severe/critical illness or death and death increased. The preventive effect against severe/critical illness or death at ≥60 years was (OR: 0.669; CI: 0.624 - 0.717), at ≥70 years was (OR: 0.614; CI: 0.570 - 0.661), and at ≥80 years was (OR: 0.563; CI: 0.515 - 0.615). The preventive effect against death at ≥60 years was (OR: 0.729; CI: 0.663 - 0.802), at ≥70 years was (OR: 0.676; CI: 0.612 - 0.747), and at ≥80 years was (OR: 0.622; CI: 0.554 - 0.698).

CONCLUSION

Although molnupiravir showed a relatively weak preventive effect against severe/critical illness or death (29%) and death (25%) among patients with COVID-19, it exhibited a stronger protective effect in older patients than in younger patients. In particular, the preventive effect against severe/critical illness or death (44%) and death (38%) in those aged ≥80 years was pronounced. This study strongly suggests that molnupiravir administration can alleviate the burden on the medical system, and treat patients with COVID-19 effectively by reducing its progression to severe disease and death.

Effectiveness of Nirmatrelvir-Ritonavir Against the Development of Post-COVID-19 Conditions Among U.S. Veterans : A Target Trial Emulation

BACKGROUND

COVID-19 has been linked to the development of many post-COVID-19 conditions (PCCs) after acute infection. Limited information is available on the effectiveness of oral antivirals used to treat acute COVID-19 in preventing the development of PCCs.

OBJECTIVE

To measure the effectiveness of outpatient treatment of COVID-19 with nirmatrelvir-ritonavir in preventing PCCs.

DESIGN

Retrospective target trial emulation study comparing matched cohorts receiving nirmatrelvir-ritonavir versus no treatment.

SETTING

Veterans Health Administration (VHA).

PARTICIPANTS

Nonhospitalized veterans in VHA care who were at risk for severe COVID-19 and tested positive for SARS-CoV-2 during January through July 2022.

INTERVENTION

Nirmatrelvir-ritonavir treatment for acute COVID-19.

MEASUREMENTS

Cumulative incidence of 31 potential PCCs at 31 to 180 days after treatment or a matched index date, including cardiac, pulmonary, renal, thromboembolic, gastrointestinal, neurologic, mental health, musculoskeletal, endocrine, and general conditions and symptoms.

RESULTS

Eighty-six percent of the participants were male, with a median age of 66 years, and 17.5% were unvaccinated. Baseline characteristics were well balanced between participants treated with nirmatrelvir-ritonavir and matched untreated comparators. No differences were observed between participants treated with nirmatrelvir-ritonavir (n = 9593) and their matched untreated comparators in the incidence of most PCCs examined individually or grouped by organ system, except for lower combined risk for venous thromboembolism and pulmonary embolism (subhazard ratio, 0.65 [95% CI, 0.44 to 0.97]; cumulative incidence difference, -0.29 percentage points [CI, -0.52 to -0.05 percentage points]).

LIMITATIONS

Ascertainment of PCCs using International Classification of Diseases, 10th Revision, codes may be inaccurate. Evaluation of many outcomes could have resulted in spurious associations with combined thromboembolic events by chance.

CONCLUSION

Out of 31 potential PCCs, only combined thromboembolic events seemed to be reduced by nirmatrelvir-ritonavir.

PRIMARY FUNDING SOURCE

U.S. Department of Veterans Affairs.

Target trial emulation with multi-state model analysis to assess treatment effectiveness using clinical COVID-19 data

BACKGROUND

Real-world observational data are an important source of evidence on the treatment effectiveness for patients hospitalized with coronavirus disease 2019 (COVID-19). However, observational studies evaluating treatment effectiveness based on longitudinal data are often prone to methodological biases such as immortal time bias, confounding bias, and competing risks.

METHODS

For exemplary target trial emulation, we used a cohort of patients hospitalized with COVID-19 (n = 501) in a single centre. We described the methodology for evaluating the effectiveness of a single-dose treatment, emulated a trial using real-world data, and drafted a hypothetical study protocol describing the main components. To avoid immortal time and time-fixed confounding biases, we applied the clone-censor-weight technique. We set a 5-day grace period as a period of time when treatment could be initiated. We used the inverse probability of censoring weights to account for the selection bias introduced by artificial censoring. To estimate the treatment effects, we took the multi-state model approach. We considered a multi-state model with five states. The primary endpoint was defined as clinical severity status, assessed by a 5-point ordinal scale on day 30. Differences between the treatment group and standard of care treatment group were calculated using a proportional odds model and shown as odds ratios. Additionally, the weighted cause-specific hazards and transition probabilities for each treatment arm were presented.

RESULTS

Our study demonstrates that trial emulation with a multi-state model analysis is a suitable approach to address observational data limitations, evaluate treatment effects on clinically heterogeneous in-hospital death and discharge alive endpoints, and consider the intermediate state of admission to ICU. The multi-state model analysis allows us to summarize results using stacked probability plots that make it easier to interpret results.

CONCLUSIONS

Extending the emulated target trial approach to multi-state model analysis complements treatment effectiveness analysis by gaining information on competing events. Combining two methodologies offers an option to address immortal time bias, confounding bias, and competing risk events. This methodological approach can provide additional insight for decision-making, particularly when data from randomized controlled trials (RCTs) are unavailable.

Postacute sequelae of COVID-19 at 2 years

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to postacute sequelae in multiple organ systems, but evidence is mostly limited to the first year postinfection. We built a cohort of 138,818 individuals with SARS-CoV-2 infection and 5,985,227 noninfected control group from the US Department of Veterans Affairs and followed them for 2 years to estimate the risks of death and 80 prespecified postacute sequelae of COVID-19 (PASC) according to care setting during the acute phase of infection. The increased risk of death was not significant beyond 6 months after infection among nonhospitalized but remained significantly elevated through the 2 years in hospitalized individuals. Within the 80 prespecified sequelae, 69% and 35% of them became not significant at 2 years after infection among nonhospitalized and hospitalized individuals, respectively. Cumulatively at 2 years, PASC contributed 80.4 (95% confidence interval (CI): 71.6-89.6) and 642.8 (95% CI: 596.9-689.3) disability-adjusted life years (DALYs) per 1,000 persons among nonhospitalized and hospitalized individuals; 25.3% (18.9-31.0%) and 21.3% (18.2-24.5%) of the cumulative 2-year DALYs in nonhospitalized and hospitalized were from the second year. In sum, while risks of many sequelae declined 2 years after infection, the substantial cumulative burden of health loss due to PASC calls for attention to the care needs of people with long-term health effects due to SARS-CoV-2 infection.

Effectiveness of COVID-19 Treatment With Nirmatrelvir-Ritonavir or Molnupiravir Among U.S. Veterans: Target Trial Emulation Studies With One-Month and Six-Month Outcomes

BACKGROUND

Information about the effectiveness of oral antivirals in preventing short- and long-term COVID-19-related outcomes in the setting of Omicron variant transmission and COVID-19 vaccination is limited.

OBJECTIVE

To measure the effectiveness of nirmatrelvir-ritonavir and molnupiravir for outpatient treatment of COVID-19.

DESIGN

Three retrospective target trial emulation studies comparing matched cohorts of nirmatrelvir-ritonavir versus no treatment, molnupiravir versus no treatment, and nirmatrelvir-ritonavir versus molnupiravir.

SETTING

Veterans Health Administration (VHA).

PARTICIPANTS

Nonhospitalized veterans in VHA care who were at risk for severe COVID-19 and tested positive for SARS-CoV-2 during January through July 2022.

INTERVENTION

Nirmatrelvir-ritonavir or molnupiravir pharmacotherapy.

MEASUREMENTS

Incidence of any hospitalization or all-cause mortality at 30 days and from 31 to 180 days.

RESULTS

Eighty-seven percent of participants were male; the median age was 66 years, and 18% were unvaccinated. Compared with matched untreated control participants, those treated with nirmatrelvir-ritonavir (n = 9607) had lower 30-day risk for hospitalization (22.07 vs. 30.32 per 1000 participants; risk difference [RD], -8.25 [95% CI, -12.27 to -4.23] per 1000 participants) and death (1.25 vs. 5.47 per 1000 participants; RD, -4.22 [CI, -5.45 to -3.00] per 1000 participants). Among persons alive at day 31, reductions were seen in 31- to 180-day incidence of death (hazard ratio, 0.66 [CI, 0.49 to 0.89]) but not hospitalization (subhazard ratio, 0.90 [CI, 0.79 to 1.02]). Molnupiravir-treated participants (n = 3504) had lower 30-day and 31- to 180-day risks for death (3.14 vs. 13.56 per 1000 participants at 30 days; RD, -10.42 [CI, -13.49 to -7.35] per 1000 participants; hazard ratio at 31 to 180 days, 0.67 [CI, 0.48 to 0.95]) but not hospitalization. A difference in 30-day or 31- to 180-day risk for hospitalization or death was not observed between matched nirmatrelvir- or molnupiravir-treated participants.

LIMITATION

The date of COVID-19 symptom onset for most veterans was unknown.

CONCLUSION

Nirmatrelvir-ritonavir was effective in reducing 30-day hospitalization and death. Molnupiravir was associated with a benefit for 30-day mortality but not hospitalization. Further reductions in mortality from 31 to 180 days were observed with both antivirals.

PRIMARY FUNDING SOURCE

U.S. Department of Veterans Affairs.

Efficacy of Molnupiravir for the Treatment of Mild or Moderate COVID-19 in Adults: A Meta-Analysis

The aim of this meta-analysis is to evaluate the efficacy of molnupiravir among mild or moderate COVID-19 patients. This meta-analysis was reported according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Two authors independently performed a comprehensive search for relevant studies in PubMed, Cochrane Library, and Web of Science. The keywords used to search for relevant records were "Molnupiravir," "COVID-19," and "efficacy." This meta-analysis included studies that compared the effectiveness of molnupiravir with a placebo for COVID-19 treatment. The primary outcome assessed in this meta-analysis was the composite of hospitalization and all-cause mortality (30 days). In addition, we assessed all-cause mortality and hospitalization separately and the number of patients who tested negative for viral RNA on day five. A total of 10 studies were included in the meta-analysis. Among the 10 studies, five were randomized controlled trials and five were observational studies. Based on the results presented in the meta-analysis, it can be concluded that molnupiravir has a significant impact on reducing all-cause mortality and improving the proportion of patients who test negative for viral RNA on day five. The risk of hospitalization and composite outcome was also lower in molnupiravir-treated patients, although the difference was statistically insignificant. The subgroup analysis showed consistent results across all subgroups, indicating that the effect of molnupiravir is consistent regardless of patient characteristics.

Molnupiravir and risk of post-acute sequelae of covid-19: cohort study

OBJECTIVE

To examine whether treatment with the antiviral agent molnupiravir during the first five days of SARS-CoV-2 infection is associated with reduced risk of post-acute adverse health outcomes.

DESIGN

Cohort study.

SETTING

US Department of Veterans Affairs.

PARTICIPANTS

229 286 participants who tested positive for SARS-CoV-2 between 5 January 2022 and 15 January 2023, had at least one risk factor for progression to severe covid-19, and survived the first 30 days after testing positive were enrolled. 11 472 participants received a prescription for molnupiravir within five days of the positive test result and 217 814 received no covid-19 antiviral or antibody treatment (no treatment group).

MAIN OUTCOME MEASURES

Risks of post-acute sequelae of SARS-CoV-2 (PASC, defined based on a prespecified set of 13 post-acute sequelae), post-acute death, post-acute hospital admission, and each individual post-acute sequela between the molnupiravir group and no treatment group were examined after application of inverse probability weighting to balance the treatment and no treatment groups. Post-acute outcomes were ascertained from 30 days after the first SARS-CoV-2 positive test result until end of follow-up. Risks on the relative scale (relative risk or hazard ratio) and absolute scale (absolute risk reduction at 180 days) were estimated.

RESULTS

Compared with no treatment, molnupiravir use within five days of a positive SARS-CoV-2 test result was associated with reduced risk of PASC (relative risk 0.86 (95% confidence interval 0.83 to 0.89); absolute risk reduction at 180 days 2.97% (95% confidence interval 2.31% to 3.60%)), post-acute death (hazard ratio 0.62 (0.52 to 0.74); 0.87% (0.62% to 1.13%)), and post-acute hospital admission (0.86 (0.80 to 0.93); 1.32% (0.72% to 1.92%)). Molnupiravir was associated with reduced risk of eight of the 13 post-acute sequelae: dysrhythmia, pulmonary embolism, deep vein thrombosis, fatigue and malaise, liver disease, acute kidney injury, muscle pain, and neurocognitive impairment. Molnupiravir was also associated with reduced risk of PASC in people who had not received a covid-19 vaccine, had received at one or two vaccine doses, and had received a booster dose, and in people with primary SARS-CoV-2 infection and reinfection.

CONCLUSIONS

In people with SARS-CoV-2 infection and at least one risk factor for progression to severe covid-19, compared with no treatment, molnupiravir use within five days of infection was associated with reduced risk of PASC in people who had not received a covid-19 vaccine, had received one or two vaccine doses, and had received a booster dose, and in those with primary SARS-CoV-2 infection and reinfection. Among people at high risk of progression to severe covid-19, molnupiravir use within five days of SARS-CoV-2 infection may be a viable approach to reduce the risk of PASC.

Effectiveness, Tolerability and Prescribing Choice of Antiviral Molecules Molnupiravir, Remdesivir and Nirmatrelvir/r: A Real-World Comparison in the First Ten Months of Use

In 2022, three antiviral drugs-molnupiravir, remdesivir and nirmatrelvir/ritonavir-were introduced for treatment of mild-to-moderate COVID-19 in high-risk patients. The aim of this study is the evaluation of their effectiveness and tolerability in a real-life setting. A single-center observational study was set up, with the involvement of 1118 patients, with complete follow-up data, treated between the 5th of January and the 3rd of October 2022 at Santa Maria Goretti's hospital in Latina, Central Italy. A univariable and a multivariable analysis were performed on clinical and demographic data and composite outcome, the persistence of symptoms at 30 days and time to negativization, respectively. The three antivirals showed a similar effectiveness in containing the progression of the infection to severe COVID-19 and a good tolerability in the absence of serious adverse effects. Persistence of symptoms after 30 days was more common in females than males and less common in patients treated with molnupiravir and nirmatrelvir/r. The availability of different antiviral molecules is a strong tool and, if correctly prescribed, they can have a significant role in changing the natural history of infection for frail persons, in which vaccination could be not sufficient for the prevention of severe COVID-19.

Nirmatrelvir and risk of hospital admission or death in adults with covid-19: emulation of a randomized target trial using electronic health records

OBJECTIVE

To estimate the effectiveness of nirmatrelvir, compared with no treatment, in reducing admission to hospital or death at 30 days in people infected with the SARS-CoV-2 virus and at risk of developing severe disease, according to vaccination status and history of previous SARS-CoV-2 infection.

DESIGN

Emulation of a randomized target trial with electronic health records.

SETTING

Healthcare databases of the US Department of Veterans Affairs PARTICIPANTS: 256 288 participants with a SARS-CoV-2 positive test result and at least one risk factor for developing severe covid-19 disease, between 3 January and 30 November 2022. 31 524 were treated with nirmatrelvir within five days of testing positive for SARS-CoV-2 and 224 764 received no treatment.

MAIN OUTCOME MEASURES

The effectiveness of starting nirmatrelvir within five days of a positive SARS-CoV-2 test result versus no treatment in reducing the risk of admission to hospital or death at 30 days was estimated in those who were not vaccinated, in those who received one or two doses of vaccine, and those who received a vaccine booster and, separately, in participants with a primary SARS-CoV-2 infection or reinfection. The inverse probability weighting method was used to balance personal and health characteristics between the groups. Relative risk and absolute risk reduction were computed from cumulative incidence at 30 days, estimated by weighted Kaplan-Meier estimator.

RESULTS

Among people who were not vaccinated (n=76 763; 5338 nirmatrelvir and 71 425 no treatment), compared with no treatment, the relative risk of nirmatrelvir in reducing admission to hospital or death at 30 days was 0.60 (95% confidence interval 0.50 to 0.71); the absolute risk reduction was 1.83% (95% confidence interval 1.29% to 2.49%). The relative risk and absolute risk reduction, compared with no treatment, were 0.65 (0.57 to 0.74) and 1.27% (0.90% to 1.61%), respectively, in people who received one or two doses of vaccine (n=84 620; 7989 nirmatrelvir and 76 631 no treatment); 0.64 (0.58 to 0.71) and 1.05% (0.85% to 1.27%) in individuals who received a booster dose of vaccine (n=94 905; 18 197 nirmatrelvir and 76 708 no treatment); 0.61 (0.57 to 0.65) and 1.36% (1.19% to 1.53%) in participants with a primary SARS-CoV-2 infection (n=228 081; 26 350 nirmatrelvir and 201 731 no treatment); and 0.74 (0.63 to 0.87) and 0.79% (0.36% to 1.18%) in participants who were reinfected with the SARS-CoV-2 virus (n=28 207; 5174 nirmatrelvir and 23 033 no treatment). Nirmatrelvir was associated with a reduced risk of admission to hospital or death in those aged ≤65 years and > 65 years; in men and women; in black and white participants; in those with 1-2, 3-4, and ≥5 risk factors for progression to severe covid-19 illness; and in those infected during the omicron BA.1 or BA.2 predominant era, and the BA.5 predominant era.

CONCLUSIONS

In people with SARS-CoV-2 infection who were at risk of developing severe disease, compared with no treatment, nirmatrelvir was associated with a reduced risk of admission to hospital or death at 30 days in people who were not vaccinated, vaccinated, and had received a booster vaccine, and in those with a primary SARS-CoV-2 infection and reinfection.

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.