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1.
Ann Intern Med ; 2022 Jul 05.
Article in English | MEDLINE | ID: covidwho-1924597

ABSTRACT

BACKGROUND: Immunoassays for determining past SARS-CoV-2 infection have not been systematically evaluated in vaccinated persons in comparison with unvaccinated persons. OBJECTIVE: To evaluate antinucleocapsid antibody (anti-N Ab) seropositivity in mRNA-1273 (Moderna) vaccinees with breakthrough SARS-CoV-2 infection. DESIGN: Nested substudy of a phase 3 randomized, double-blind, placebo-controlled vaccine efficacy trial. (ClinicalTrials.gov: NCT04470427). SETTING: 99 sites in the United States, July 2020 through March 2021. PARTICIPANTS: Participants were aged 18 years or older, had no known history of SARS-CoV-2 infection, and were at risk for SARS-CoV-2 infection or severe COVID-19. Substudy participants were diagnosed with SARS-CoV-2 infection during the trial's blinded phase. INTERVENTION: 2 mRNA-1273 or placebo injections 28 days apart. MEASUREMENTS: Nasopharyngeal swabs from days 1 and 29 (vaccination days) and from symptom-prompted illness visits were tested for SARS-CoV-2 via polymerase chain reaction (PCR). Serum samples from days 1, 29, and 57 and the participant decision visit (PDV, when participants were informed of treatment assignment; median day 149) were tested for anti-N Abs by the Elecsys immunoassay. RESULTS: Among 700 participants with PCR-confirmed COVID-19 illness during the blinded phase of the trial (through March 2021), seroconversion to anti-N Abs (median of 53 days after diagnosis) occurred in 21 of 52 mRNA-1273 vaccinees (40% [95% CI, 27% to 54%]) versus 605 of 648 placebo recipients (93% [CI, 92% to 95%]). Each 1-log increase in SARS-CoV-2 viral copies at diagnosis was associated with 90% higher odds of anti-N Ab seroconversion (odds ratio, 1.90 [CI, 1.59 to 2.28]). LIMITATION: The scope was restricted to mRNA-1273 vaccinees and the Elecsys assay, the sample size was small, data on Delta and Omicron infections were lacking, and the analysis did not address a prespecified objective of the trial. CONCLUSION: Vaccination status should be considered when interpreting seroprevalence and seropositivity data based solely on anti-N Ab testing. Primary Funding source: National Institute of Allergy and Infectious Diseases of the National Institutes of Health.

2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-334206

ABSTRACT

Importance The performance of immunoassays for determining past SARS-CoV-2 infection, which were developed in unvaccinated individuals, has not been assessed in vaccinated individuals. Objective To evaluate anti-nucleocapsid antibody (anti-N Ab) seropositivity in mRNA-1273 vaccine efficacy trial participants after SARS-CoV-2 infection during the trial’s blinded phase. Design Nested analysis in a Phase 3 randomized, placebo-controlled vaccine efficacy trial. Nasopharyngeal swabs for SARS-CoV-2 PCR testing were taken from all participants on Day 1 and Day 29 (vaccination days), and during symptom-prompted illness visits. Serum samples from Days 1, 29, 57, and the Participant Decision Visit (PDV, when participants were informed of treatment assignment, median day 149) were tested for anti-N Abs. Setting Multicenter, randomized, double-blind, placebo-controlled trial at 99 sites in the US. Participants Trial participants were ≥ 18 years old with no known history of SARS-CoV-2 infection and at appreciable risk of SARS-CoV-2 infection and/or high risk of severe Covid-19. Nested sub-study consists of participants with SARS-CoV-2 infection during the blinded phase of the trial. Intervention Two mRNA-1273 (Moderna) or Placebo injections, 28 days apart. Main Outcome and Measure Detection of serum anti-N Abs by the Elecsys (Roche) immunoassay in samples taken at the PDV from participants with SARS-CoV-2 infection during the blinded phase. The hypothesis tested was that mRNA-1273 recipients have different anti-N Ab seroconversion and/or seroreversion profiles after SARS-CoV-2 infection, compared to placebo recipients. The hypothesis was formed during data collection;all main analyses were pre-specified before being conducted. Results We analyzed data from 1,789 participants (1,298 placebo recipients and 491 vaccine recipients) with SARS-CoV-2 infection during the blinded phase (through March 2021). Among participants with PCR-confirmed Covid-19 illness, seroconversion to anti-N Abs at a median follow up of 53 days post diagnosis occurred in 21/52 (40%) of the mRNA-1273 vaccine recipients vs. 605/648 (93%) of the placebo recipients (p < 0.001). Higher SARS-CoV-2 viral copies at diagnosis was associated with a higher likelihood of anti-N Ab seropositivity (odds ratio 1.90 per 1-log increase;95% confidence interval 1.59, 2.28). Conclusions and Relevance As a marker of recent infection, anti-N Abs may have lower sensitivity in mRNA-1273-vaccinated persons who become infected. Vaccination status should be considered when interpreting seroprevalence and seropositivity data based solely on anti-N Ab testing Trial Registration ClinicalTrials.gov NCT04470427 Key Points Question Does prior mRNA-1273 vaccination influence anti-nucleocapsid antibody seroconversion and/or seroreversion after SARS-CoV-2 infection? Findings Among participants in the mRNA-1273 vaccine efficacy trial with PCR-confirmed Covid-19, anti-nucleocapsid antibody seroconversion at the time of study unblinding (median 53 days post diagnosis and 149 days post enrollment) occurred in 40% of the mRNA-1273 vaccine recipients vs. 93% of the placebo recipients, a significant difference. Higher SARS-CoV-2 viral copy number upon diagnosis was associated with a greater chance of anti-nucleocapsid antibody seropositivity (odds ratio 1.90 per 1-log increase;95% confidence interval 1.59, 2.28). All infections analyzed occurred prior to the circulation of delta and omicron viral variants. Meaning Conclusions: about the prevalence and incidence of SARS-CoV-2 infection in vaccinated persons based on anti-nucleocapsid antibody assays need to be weighed in the context of these results.

3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-332856

ABSTRACT

Anti-spike IgG binding antibody, anti-receptor binding domain IgG antibody, and pseudovirus neutralizing antibody measurements four weeks post-vaccination were assessed as correlates of risk of moderate to severe-critical COVID-19 outcomes through 83 days post-vaccination and as correlates of protection following a single dose of Ad26.COV2.S COVID-19 vaccine in the placebo-controlled phase of ENSEMBLE, an international, randomized efficacy trial. Each marker had evidence as a correlate of risk and of protection, with strongest evidence for 50% inhibitory dilution (ID50) neutralizing antibody titer. The outcome hazard ratio was 0.49 (95% confidence interval 0.29, 0.81;p=0.006) per 10-fold increase in ID50;vaccine efficacy was 60% (43, 72%) at nonquantifiable ID50 (< 2.7 IU50/ml) and rose to 89% (78, 96%) at ID50 = 96.3 IU50/ml. Comparison of the vaccine efficacy by ID50 titer curves for ENSEMBLE-US, the COVE trial of the mRNA-1273 vaccine, and the COV002-UK trial of the AZD1222 vaccine supported consistency of the ID50 titer correlate of protection across trials and vaccine types.

4.
Stat Med ; 41(16): 3076-3089, 2022 Jul 20.
Article in English | MEDLINE | ID: covidwho-1782695

ABSTRACT

SARS-CoV-2 continues to evolve and the vaccine efficacy against variants is challenging to estimate. It is now common in phase III vaccine trials to provide vaccine to those randomized to placebo once efficacy has been demonstrated, precluding a direct assessment of placebo controlled vaccine efficacy after placebo vaccination. In this work, we extend methods developed for estimating vaccine efficacy post placebo vaccination to allow variant specific time varying vaccine efficacy, where time is measured since vaccination. The key idea is to infer counterfactual strain specific placebo case counts by using surveillance data that provide the proportions of the different strains. This blending of clinical trial and observational data allows estimation of strain-specific time varying vaccine efficacy, or sieve effects, including for strains that emerge after placebo vaccination. The key requirements are that the surveillance strain distribution accurately reflects the strain distribution for a placebo group throughout follow-up after placebo group vaccination, and that at least one strain is present before and after placebo vaccination. For illustration, we develop a Poisson approach for an idealized design under a rare disease assumption and then use a proportional hazards model to address staggered entry, staggered crossover, and smoothly varying strain specific vaccine efficacy. We evaluate these methods by theoretical work and simulations, and demonstrate that useful estimation of the efficacy profile is possible for strains that emerge after vaccination of the placebo group. An important principle is to incorporate sensitivity analyses to guard against misspecification of the strain distribution.


Subject(s)
COVID-19 Vaccines , COVID-19 , Vaccine Efficacy , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Cross-Over Studies , Humans , Observational Studies as Topic , Placebos , Proportional Hazards Models , Randomized Controlled Trials as Topic , SARS-CoV-2 , Vaccination
5.
Ann Intern Med ; 175(3): 444-445, 2022 03.
Article in English | MEDLINE | ID: covidwho-1766121

Subject(s)
Illusions , Humans , Vaccination
6.
Crit Care Med ; 50(7): 1051-1062, 2022 Jul 01.
Article in English | MEDLINE | ID: covidwho-1752195

ABSTRACT

OBJECTIVES: Prior research has hypothesized the Sequential Organ Failure Assessment (SOFA) score to be a poor predictor of mortality in mechanically ventilated patients with COVID-19. Yet, several U.S. states have proposed SOFA-based algorithms for ventilator triage during crisis standards of care. Using a large cohort of mechanically ventilated patients with COVID-19, we externally validated the predictive capacity of the preintubation SOFA score for mortality prediction with and without other commonly used algorithm elements. DESIGN: Multicenter, retrospective cohort study using electronic health record data. SETTING: Eighty-six U.S. health systems. PATIENTS: Patients with COVID-19 hospitalized between January 1, 2020, and February 14, 2021, and subsequently initiated on mechanical ventilation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 15,122 mechanically ventilated patients with COVID-19, SOFA score alone demonstrated poor discriminant accuracy for inhospital mortality in mechanically ventilated patients using the validation cohort (area under the receiver operating characteristic curve [AUC], 0.66; 95% CI, 0.65-0.67). Discriminant accuracy was even poorer using SOFA score categories (AUC, 0.54; 95% CI, 0.54-0.55). Age alone demonstrated greater discriminant accuracy for inhospital mortality than SOFA score (AUC, 0.71; 95% CI, 0.69-0.72). Discriminant accuracy for mortality improved upon addition of age to the continuous SOFA score (AUC, 0.74; 95% CI, 0.73-0.76) and categorized SOFA score (AUC, 0.72; 95% CI, 0.71-0.73) models, respectively. The addition of comorbidities did not substantially increase model discrimination. Of 36 U.S. states with crisis standards of care guidelines containing ventilator triage algorithms, 31 (86%) feature the SOFA score. Of these, 25 (81%) rely heavily on the SOFA score (12 exclusively propose SOFA; 13 place highest weight on SOFA or propose SOFA with one other variable). CONCLUSIONS: In a U.S. cohort of over 15,000 ventilated patients with COVID-19, the SOFA score displayed poor predictive accuracy for short-term mortality. Our findings warrant reappraisal of the SOFA score's implementation and weightage in existing ventilator triage pathways in current U.S. crisis standards of care guidelines.


Subject(s)
COVID-19 , Organ Dysfunction Scores , Algorithms , Delivery of Health Care , Electronic Health Records , Hospital Mortality , Humans , Intensive Care Units , Prognosis , ROC Curve , Retrospective Studies , Triage , Ventilators, Mechanical
7.
Biostatistics ; 2022 Mar 17.
Article in English | MEDLINE | ID: covidwho-1744154

ABSTRACT

Vaccine trials are generally designed to assess efficacy on clinical disease. The vaccine effect on infection, while important both as a proxy for transmission and to describe a vaccine's entire effects, requires frequent (e.g., twice a week) longitudinal sampling to capture all infections. Such sampling may not always be feasible. A logistically easy approach is to collect a sample to test for infection at a regularly scheduled visit. Such point or cross-sectional sampling does not permit estimation of classic vaccine efficacy on infection, as long duration infections are sampled with higher probability. Building on work by Rinta-Kokko and others (2009) and Lipsitch and Kahn (2021), we evaluate proxies of the vaccine effect on transmission at a point in time; the vaccine efficacy on prevalent infection and on prevalent viral load, VE$_{\rm PI}$ and VE$_{\rm PVL}$, respectively. Longer infections with higher viral loads should have more transmission potential and prevalent vaccine efficacy naturally captures this aspect. We demonstrate how these parameters obtain from an underlying proportional hazards model for infection and allow for waning efficacy on infection, duration, and viral load. We estimate these parameters based on regression models with either repeated cross-sectional sampling or frequent longitudinal sampling. We evaluate the methods by simulation and analyze a phase III vaccine trial with polymerase chain reaction (PCR) cross-sectional sampling for subclinical infection.

8.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-310487

ABSTRACT

Randomized vaccine trials are used to assess vaccine efficacy and to characterize the durability of vaccine induced protection. If efficacy is demonstrated, the treatment of placebo volunteers becomes an issue. For COVID-19 vaccine trials, there is broad consensus that placebo volunteers should be offered a vaccine once efficacy has been established. This will likely lead to most placebo volunteers crossing over to the vaccine arm, thus complicating the assessment of long term durability. We show how to analyze durability following placebo crossover and demonstrate that the vaccine efficacy profile that would be observed in a placebo controlled trial is recoverable in a trial with placebo crossover. This result holds no matter when the crossover occurs and with no assumptions about the form of the efficacy profile. We only require that the vaccine efficacy profile applies to the newly vaccinated irrespective of the timing of vaccination. We develop different methods to estimate efficacy within the context of a proportional hazards regression model and explore via simulation the implications of placebo crossover for estimation of vaccine efficacy under different efficacy dynamics and study designs. We apply our methods to simulated COVID-19 vaccine trials with durable and waning vaccine efficacy and a total follow-up of two years.

9.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-309595

ABSTRACT

Introduction: Endpoint choice for randomized controlled trials of treatments for COVID-19 is complex. A new disease brings many uncertainties, but trials must start rapidly. COVID-19 is heterogeneous, ranging from mild disease that improves within days to critical disease that can last weeks and can end in death. While improvement in mortality would provide unquestionable evidence about clinical significance of a treatment, sample sizes for a study evaluating mortality are large and may be impractical. Furthermore, patient states in between "cure" and "death" represent meaningful distinctions. Clinical severity scores have been proposed as an alternative. However, the appropriate summary measure for severity scores has been the subject of debate, particularly in relating to the uncertainty about the time-course of COVID-19. Outcomes measured at fixed time-points may risk missing the time of clinical benefit. An endpoint such as time-to-improvement (or recovery), avoids the timing problem. However, some have argued that power losses will result from reducing the ordinal scale to a binary state of "recovered" vs "not recovered." Methods: We evaluate statistical power for possible trial endpoints for COVID-19 treatment trials using simulation models and data from two recent COVID-19 treatment trials. Results: Power for fixed-time point methods depends heavily on the time selected for evaluation. Time-to-improvement (or recovery) analyses do not specify a time-point. Time-to-event approaches have reasonable statistical power, even when compared to a fixed time-point method evaluated at the optimal time. Discussion: Time-to-event analyses methods have advantages in the COVID-19 setting, unless the optimal time for evaluating treatment effect is known in advance. Even when the optimal time is known, a time-to-event approach may increase power for interim analyses.

10.
Science ; 375(6576): 43-50, 2022 Jan 07.
Article in English | MEDLINE | ID: covidwho-1649486

ABSTRACT

In the coronavirus efficacy (COVE) phase 3 clinical trial, vaccine recipients were assessed for neutralizing and binding antibodies as correlates of risk for COVID-19 disease and as correlates of protection. These immune markers were measured at the time of second vaccination and 4 weeks later, with values reported in standardized World Health Organization international units. All markers were inversely associated with COVID-19 risk and directly associated with vaccine efficacy. Vaccine recipients with postvaccination 50% neutralization titers 10, 100, and 1000 had estimated vaccine efficacies of 78% (95% confidence interval, 54 to 89%), 91% (87 to 94%), and 96% (94 to 98%), respectively. These results help define immune marker correlates of protection and may guide approval decisions for messenger RNA (mRNA) COVID-19 vaccines and other COVID-19 vaccines.


Subject(s)
2019-nCoV Vaccine mRNA-1273/immunology , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccine Efficacy , Adolescent , Adult , Aged , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Clinical Trials, Phase III as Topic , Female , Humans , Immunogenicity, Vaccine , Male , Middle Aged , Randomized Controlled Trials as Topic , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus/immunology , Young Adult
11.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294719

ABSTRACT

Summary SARS-CoV-2 continues to evolve and the vaccine efficacy against variants is challenging to estimate. It is now common in phase III vaccine trials to provide vaccine to those randomized to placebo once efficacy has been demonstrated, precluding a direct assessment of placebo controlled vaccine efficacy after placebo vaccination. In this work we extend methods developed for estimating vaccine efficacy post placebo vaccination to allow variant specific time varying vaccine efficacy, where time is measured since vaccination. The key idea is to infer counterfactual strain specific placebo case counts by using surveillance data that provide the proportions of the different strains. This blending of clinical trial and observational data allows estimation of strain-specific time varying vaccine efficacy, or sieve effects, including for strains that emergent after placebo vaccination. The key requirements are that surveillance strain distribution accurately reflect the strain distribution for a placebo group, throughout follow-up after placebo group vaccination and that at least one strain is present before and after placebo vaccination. For illustration, we develop a Poisson approach for an idealized design under a rare disease assumption and then use a proportional hazards modeling to better reflect the complexities of field trials with staggered entry, crossover, and smoothly varying strain specific vaccine efficacy We evaluate these by theoretical work and simulations, and demonstrate that useful estimation of the efficacy profile is possible for strains that emerge after vaccination of the placebo group. An important principle is to incorporate sensitivity analyses to guard against mis-specfication of the strain distribution. We also provide an approach for use when genotyping of the infecting strains of the trial participants has not been done.

12.
[Unspecified Source]; 2020.
Preprint in English | [Unspecified Source] | ID: ppcovidwho-292761

ABSTRACT

Phase III platform trials are increasingly used to evaluate a sequence of treatments for a specific disease. Traditional approaches to structure such trials tend to focus on the sequential questions rather than the performance of the entire enterprise. We consider two-stage trials where an early evaluation is used to determine whether to continue with an individual study. To evaluate performance, we use the ratio of expected wins (RW), that is, the expected number of reported efficacious treatments using a two-stage approach compared to that using standard phase III trials. We approximate the test statistics during the course of a single trial using Brownian Motion and determine the optimal stage 1 time and type I error rate to maximize RW for fixed power. At times, a surrogate or intermediate endpoint may provide a quicker read on potential efficacy than use of the primary endpoint at stage 1. We generalize our approach to the surrogate endpoint setting and show improved performance, provided a good quality and powerful surrogate is available. We apply our methods to the design of a platform trial to evaluate treatments for COVID-19 disease.

14.
N Engl J Med ; 385(19): 1774-1785, 2021 Nov 04.
Article in English | MEDLINE | ID: covidwho-1434206

ABSTRACT

BACKGROUND: At interim analysis in a phase 3, observer-blinded, placebo-controlled clinical trial, the mRNA-1273 vaccine showed 94.1% efficacy in preventing coronavirus disease 2019 (Covid-19). After emergency use of the vaccine was authorized, the protocol was amended to include an open-label phase. Final analyses of efficacy and safety data from the blinded phase of the trial are reported. METHODS: We enrolled volunteers who were at high risk for Covid-19 or its complications; participants were randomly assigned in a 1:1 ratio to receive two intramuscular injections of mRNA-1273 (100 µg) or placebo, 28 days apart, at 99 centers across the United States. The primary end point was prevention of Covid-19 illness with onset at least 14 days after the second injection in participants who had not previously been infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The data cutoff date was March 26, 2021. RESULTS: The trial enrolled 30,415 participants; 15,209 were assigned to receive the mRNA-1273 vaccine, and 15,206 to receive placebo. More than 96% of participants received both injections, 2.3% had evidence of SARS-CoV-2 infection at baseline, and the median follow-up was 5.3 months in the blinded phase. Vaccine efficacy in preventing Covid-19 illness was 93.2% (95% confidence interval [CI], 91.0 to 94.8), with 55 confirmed cases in the mRNA-1273 group (9.6 per 1000 person-years; 95% CI, 7.2 to 12.5) and 744 in the placebo group (136.6 per 1000 person-years; 95% CI, 127.0 to 146.8). The efficacy in preventing severe disease was 98.2% (95% CI, 92.8 to 99.6), with 2 cases in the mRNA-1273 group and 106 in the placebo group, and the efficacy in preventing asymptomatic infection starting 14 days after the second injection was 63.0% (95% CI, 56.6 to 68.5), with 214 cases in the mRNA-1273 group and 498 in the placebo group. Vaccine efficacy was consistent across ethnic and racial groups, age groups, and participants with coexisting conditions. No safety concerns were identified. CONCLUSIONS: The mRNA-1273 vaccine continued to be efficacious in preventing Covid-19 illness and severe disease at more than 5 months, with an acceptable safety profile, and protection against asymptomatic infection was observed. (Funded by the Biomedical Advanced Research and Development Authority and the National Institute of Allergy and Infectious Diseases; COVE ClinicalTrials.gov number, NCT04470427.).


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunogenicity, Vaccine , 2019-nCoV Vaccine mRNA-1273 , Adolescent , Adult , Aged , COVID-19/epidemiology , COVID-19 Vaccines/adverse effects , Follow-Up Studies , Humans , Immunization, Secondary , Incidence , Intention to Treat Analysis , Male , Middle Aged , Patient Acuity , Single-Blind Method , Treatment Outcome , Young Adult
15.
J Infect Dis ; 224(1): 49-59, 2021 07 02.
Article in English | MEDLINE | ID: covidwho-1294731

ABSTRACT

BACKGROUND: We investigated frequency of reinfection with seasonal human coronaviruses (HCoVs) and serum antibody response following infection over 8 years in the Household Influenza Vaccine Evaluation (HIVE) cohort. METHODS: Households were followed annually for identification of acute respiratory illness with reverse-transcription polymerase chain reaction-confirmed HCoV infection. Serum collected before and at 2 time points postinfection were tested using a multiplex binding assay to quantify antibody to seasonal, severe acute respiratory syndrome coronavirus (SARS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike proteins and SARS-CoV-2 spike subdomains and N protein. RESULTS: Of 3418 participants, 40% were followed for ≥3 years. A total of 1004 HCoV infections were documented; 303 (30%) were reinfections of any HCoV type. The number of HCoV infections ranged from 1 to 13 per individual. The mean time to reinfection with the same type was estimated at 983 days for 229E, 578 days for HKU1, 615 days for OC43, and 711 days for NL63. Binding antibody levels to seasonal HCoVs were high, with little increase postinfection, and were maintained over time. Homologous, preinfection antibody levels did not significantly correlate with odds of infection, and there was little cross-response to SARS-CoV-2 proteins. CONCLUSIONS: Reinfection with seasonal HCoVs is frequent. Binding anti-spike protein antibodies do not correlate with protection from seasonal HCoV infection.


Subject(s)
Coronavirus Infections/epidemiology , Coronavirus , Family Characteristics , Influenza Vaccines/immunology , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Severe Acute Respiratory Syndrome/epidemiology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/epidemiology , COVID-19/virology , Coinfection/epidemiology , Coronavirus/classification , Coronavirus/genetics , Coronavirus/immunology , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Coronavirus Infections/virology , Cross Reactions/immunology , Humans , Influenza Vaccines/administration & dosage , Influenza, Human/virology , Kaplan-Meier Estimate , Michigan/epidemiology , Proportional Hazards Models , Public Health Surveillance , Reinfection/epidemiology , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Seasons , Seroepidemiologic Studies , Severe Acute Respiratory Syndrome/diagnosis , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/virology , Viral Load
16.
Ann Intern Med ; 174(5): 730-731, 2021 05.
Article in English | MEDLINE | ID: covidwho-1231571

Subject(s)
COVID-19 , Humans , SARS-CoV-2
17.
Stat Med ; 40(11): 2526-2527, 2021 05 20.
Article in English | MEDLINE | ID: covidwho-1219251

ABSTRACT

Common themes from the AIDS and COVID-19 pandemics are reviewed from the vantage point of a statistician at the National Institutes of Health.


Subject(s)
Acquired Immunodeficiency Syndrome , COVID-19 , Humans , Pandemics , SARS-CoV-2
18.
Ann Intern Med ; 174(8): 1118-1125, 2021 08.
Article in English | MEDLINE | ID: covidwho-1181776

ABSTRACT

Multiple candidate vaccines to prevent COVID-19 have entered large-scale phase 3 placebo-controlled randomized clinical trials, and several have demonstrated substantial short-term efficacy. At some point after demonstration of substantial efficacy, placebo recipients should be offered the efficacious vaccine from their trial, which will occur before longer-term efficacy and safety are known. The absence of a placebo group could compromise assessment of longer-term vaccine effects. However, by continuing follow-up after vaccination of the placebo group, this study shows that placebo-controlled vaccine efficacy can be mathematically derived by assuming that the benefit of vaccination over time has the same profile for the original vaccine recipients and the original placebo recipients after their vaccination. Although this derivation provides less precise estimates than would be obtained by a standard trial where the placebo group remains unvaccinated, this proposed approach allows estimation of longer-term effect, including durability of vaccine efficacy and whether the vaccine eventually becomes harmful for some. Deferred vaccination, if done open-label, may lead to riskier behavior in the unblinded original vaccine group, confounding estimates of long-term vaccine efficacy. Hence, deferred vaccination via blinded crossover, where the vaccine group receives placebo and vice versa, would be the preferred way to assess vaccine durability and potential delayed harm. Deferred vaccination allows placebo recipients timely access to the vaccine when it would no longer be proper to maintain them on placebo, yet still allows important insights about immunologic and clinical effectiveness over time.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Clinical Trials, Phase III as Topic/standards , Randomized Controlled Trials as Topic/standards , Clinical Trials, Phase III as Topic/methods , Cross-Over Studies , Double-Blind Method , Drug Administration Schedule , Follow-Up Studies , Humans , Randomized Controlled Trials as Topic/methods , Research Design/standards , SARS-CoV-2 , Treatment Outcome
19.
N Engl J Med ; 384(5): 403-416, 2021 02 04.
Article in English | MEDLINE | ID: covidwho-998039

ABSTRACT

BACKGROUND: Vaccines are needed to prevent coronavirus disease 2019 (Covid-19) and to protect persons who are at high risk for complications. The mRNA-1273 vaccine is a lipid nanoparticle-encapsulated mRNA-based vaccine that encodes the prefusion stabilized full-length spike protein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes Covid-19. METHODS: This phase 3 randomized, observer-blinded, placebo-controlled trial was conducted at 99 centers across the United States. Persons at high risk for SARS-CoV-2 infection or its complications were randomly assigned in a 1:1 ratio to receive two intramuscular injections of mRNA-1273 (100 µg) or placebo 28 days apart. The primary end point was prevention of Covid-19 illness with onset at least 14 days after the second injection in participants who had not previously been infected with SARS-CoV-2. RESULTS: The trial enrolled 30,420 volunteers who were randomly assigned in a 1:1 ratio to receive either vaccine or placebo (15,210 participants in each group). More than 96% of participants received both injections, and 2.2% had evidence (serologic, virologic, or both) of SARS-CoV-2 infection at baseline. Symptomatic Covid-19 illness was confirmed in 185 participants in the placebo group (56.5 per 1000 person-years; 95% confidence interval [CI], 48.7 to 65.3) and in 11 participants in the mRNA-1273 group (3.3 per 1000 person-years; 95% CI, 1.7 to 6.0); vaccine efficacy was 94.1% (95% CI, 89.3 to 96.8%; P<0.001). Efficacy was similar across key secondary analyses, including assessment 14 days after the first dose, analyses that included participants who had evidence of SARS-CoV-2 infection at baseline, and analyses in participants 65 years of age or older. Severe Covid-19 occurred in 30 participants, with one fatality; all 30 were in the placebo group. Moderate, transient reactogenicity after vaccination occurred more frequently in the mRNA-1273 group. Serious adverse events were rare, and the incidence was similar in the two groups. CONCLUSIONS: The mRNA-1273 vaccine showed 94.1% efficacy at preventing Covid-19 illness, including severe disease. Aside from transient local and systemic reactions, no safety concerns were identified. (Funded by the Biomedical Advanced Research and Development Authority and the National Institute of Allergy and Infectious Diseases; COVE ClinicalTrials.gov number, NCT04470427.).


Subject(s)
COVID-19 Vaccines , COVID-19/prevention & control , SARS-CoV-2 , Adolescent , Adult , Aged , COVID-19/diagnosis , COVID-19/immunology , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , Female , Humans , Incidence , Male , Middle Aged , Patient Acuity , Single-Blind Method , Spike Glycoprotein, Coronavirus , Treatment Outcome , Young Adult
20.
N Engl J Med ; 384(7): 619-629, 2021 02 18.
Article in English | MEDLINE | ID: covidwho-990095

ABSTRACT

BACKGROUND: Convalescent plasma is frequently administered to patients with Covid-19 and has been reported, largely on the basis of observational data, to improve clinical outcomes. Minimal data are available from adequately powered randomized, controlled trials. METHODS: We randomly assigned hospitalized adult patients with severe Covid-19 pneumonia in a 2:1 ratio to receive convalescent plasma or placebo. The primary outcome was the patient's clinical status 30 days after the intervention, as measured on a six-point ordinal scale ranging from total recovery to death. RESULTS: A total of 228 patients were assigned to receive convalescent plasma and 105 to receive placebo. The median time from the onset of symptoms to enrollment in the trial was 8 days (interquartile range, 5 to 10), and hypoxemia was the most frequent severity criterion for enrollment. The infused convalescent plasma had a median titer of 1:3200 of total SARS-CoV-2 antibodies (interquartile range, 1:800 to 1:3200). No patients were lost to follow-up. At day 30 day, no significant difference was noted between the convalescent plasma group and the placebo group in the distribution of clinical outcomes according to the ordinal scale (odds ratio, 0.83; 95% confidence interval [CI], 0.52 to 1.35; P = 0.46). Overall mortality was 10.96% in the convalescent plasma group and 11.43% in the placebo group, for a risk difference of -0.46 percentage points (95% CI, -7.8 to 6.8). Total SARS-CoV-2 antibody titers tended to be higher in the convalescent plasma group at day 2 after the intervention. Adverse events and serious adverse events were similar in the two groups. CONCLUSIONS: No significant differences were observed in clinical status or overall mortality between patients treated with convalescent plasma and those who received placebo. (PlasmAr ClinicalTrials.gov number, NCT04383535.).


Subject(s)
Antibodies, Neutralizing/blood , COVID-19/therapy , Immunoglobulin G/blood , Pneumonia, Viral/therapy , SARS-CoV-2/immunology , Aged , Aged, 80 and over , Blood Component Transfusion , COVID-19/complications , COVID-19/mortality , Disease Progression , Double-Blind Method , Female , Hospitalization , Humans , Immunization, Passive , Kaplan-Meier Estimate , Male , Middle Aged , Pneumonia, Viral/etiology , Pneumonia, Viral/mortality , Severity of Illness Index
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