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1.
Clin Infect Dis ; 2023 Jun 05.
Article in English | MEDLINE | ID: covidwho-20237422

ABSTRACT

BACKGROUND: Camostat inhibits SARS-CoV-2 infection in vitro. We studied the safety and efficacy of camostat in ACTIV-2/A5401, a phase 2/3 platform trial of therapeutics for COVID-19 in non-hospitalized adults. METHODS: We conducted a phase 2 study in adults with mild-to-moderate COVID-19 randomized to oral camostat for 7 days or a pooled placebo arm. Primary outcomes were time to improvement in COVID-19 symptoms through day 28, proportion of participants with SARS-CoV-2 RNA below the lower limit of quantification (LLoQ) from nasopharyngeal (NP) swabs through day 14, and grade ≥3 treatment-emergent adverse events (TEAEs) through day 28. RESULTS: Of 216 participants (109 randomized to camostat, 107 to placebo) who initiated study intervention, 45% reported ≤5 days of symptoms at study entry and 26% met the protocol definition of higher risk of progression to severe COVID-19. Median age was 37 years. Median time to symptom improvement was 9 days in both arms (p=0.99). There were no significant differences in the proportion of participants with SARS-CoV-2 RNA

2.
Clin Infect Dis ; 2023 Apr 19.
Article in English | MEDLINE | ID: covidwho-2328287
3.
Ann Intern Med ; 176(5): 658-666, 2023 05.
Article in English | MEDLINE | ID: covidwho-2294801

ABSTRACT

BACKGROUND: Development of safe and effective SARS-CoV-2 therapeutics is a high priority. Amubarvimab and romlusevimab are noncompeting anti-SARS-CoV-2 monoclonal antibodies with an extended half-life. OBJECTIVE: To assess the safety and efficacy of amubarvimab plus romlusevimab. DESIGN: Randomized, placebo-controlled, phase 2 and 3 platform trial. (ClinicalTrials.gov: NCT04518410). SETTING: Nonhospitalized patients with COVID-19 in the United States, Brazil, South Africa, Mexico, Argentina, and the Philippines. PATIENTS: Adults within 10 days onset of symptomatic SARS-CoV-2 infection who are at high risk for clinical progression. INTERVENTION: Combination of monoclonal antibodies amubarvimab plus romlusevimab or placebo. MEASUREMENTS: Nasopharyngeal and anterior nasal swabs for SARS-CoV-2, COVID-19 symptoms, safety, and progression to hospitalization or death. RESULTS: Eight-hundred and seven participants who initiated the study intervention were included in the phase 3 analysis. Median age was 49 years (quartiles, 39 to 58); 51% were female, 18% were Black, and 50% were Hispanic or Latino. Median time from symptom onset at study entry was 6 days (quartiles, 4 to 7). Hospitalizations and/or death occurred in 9 (2.3%) participants in the amubarvimab plus romlusevimab group compared with 44 (10.7%) in the placebo group, with an estimated 79% reduction in events (P < 0.001). This reduction was similar between participants with 5 or less and more than 5 days of symptoms at study entry. Grade 3 or higher treatment-emergent adverse events through day 28 were seen less frequently among participants randomly assigned to amubarvimab plus romlusevimab (7.3%) than placebo (16.1%) (P < 0.001), with no severe infusion reactions or drug-related serious adverse events. LIMITATION: The study population was mostly unvaccinated against COVID-19 and enrolled before the spread of Omicron variants and subvariants. CONCLUSION: Amubarvimab plus romlusevimab was safe and significantly reduced the risk for hospitalization and/or death among nonhospitalized adults with mild to moderate SARS-CoV-2 infection at high risk for progression to severe disease. PRIMARY FUNDING SOURCE: National Institute of Allergy and Infectious Diseases of the National Institutes of Health.


Subject(s)
COVID-19 , Adult , Humans , Female , Middle Aged , Male , SARS-CoV-2 , Antibodies, Monoclonal , Antibodies, Viral , Double-Blind Method
4.
JAMA Netw Open ; 6(4): e2310039, 2023 04 03.
Article in English | MEDLINE | ID: covidwho-2292140

ABSTRACT

Importance: Development of effective, scalable therapeutics for SARS-CoV-2 is a priority. Objective: To test the efficacy of combined tixagevimab and cilgavimab monoclonal antibodies for early COVID-19 treatment. Design, Setting, and Participants: Two phase 2 randomized blinded placebo-controlled clinical trials within the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV)-2/A5401 platform were performed at US ambulatory sites. Nonhospitalized adults 18 years or older within 10 days of positive SARS-CoV-2 test and symptom onset were eligible and were enrolled from February 1 to May 31, 2021. Interventions: Tixagevimab-cilgavimab, 300 mg (150 mg of each component) given intravenously (IV) or 600 mg (300 mg of each component) given intramuscularly (IM) in the lateral thigh, or pooled placebo. Main Outcomes and Measures: Coprimary outcomes were time to symptom improvement through 28 days; nasopharyngeal SARS-CoV-2 RNA below the lower limit of quantification (LLOQ) on days 3, 7, or 14; and treatment-emergent grade 3 or higher adverse events through 28 days. Results: A total of 229 participants were randomized for the IM study and 119 were randomized for the IV study. The primary modified intention-to-treat population included 223 participants who initiated IM tixagevimab-cilgavimab (n = 106) or placebo treatment (n = 117) (median age, 39 [IQR, 30-48] years; 113 [50.7%] were men) and 114 who initiated IV tixagevimab-cilgavimab (n = 58) or placebo treatment (n = 56) (median age, 44 [IQR, 35-54] years; 67 [58.8%] were women). Enrollment in the IV study was stopped early based on a decision to focus on IM product development. Participants were enrolled at a median of 6 (IQR, 4-7) days from COVID-19 symptom onset. Significant differences in time to symptom improvement were not observed for IM tixagevimab-cilgavimab vs placebo or IV tixagevimab-cilgavimab vs placebo. A greater proportion in the IM tixagevimab-cilgavimab arm (69 of 86 [80.2%]) than placebo (62 of 96 [64.6%]) had nasopharyngeal SARS-CoV-2 RNA below LLOQ at day 7 (adjusted risk ratio, 1.33 [95% CI, 1.12-1.57]) but not days 3 and 14; the joint test across time points favored treatment (P = .003). Differences in the proportion below LLOQ were not observed for IV tixagevimab-cilgavimab vs placebo at any of the specified time points. There were no safety signals with either administration route. Conclusions: In these 2 phase 2 randomized clinical trials, IM or IV tixagevimab-cilgavimab was safe but did not change time to symptom improvement. Antiviral activity was more evident in the larger IM trial. Trial Registration: ClinicalTrials.gov Identifier: NCT04518410.


Subject(s)
COVID-19 , Adult , Female , Humans , Male , Antibodies, Monoclonal , COVID-19 Drug Treatment , RNA, Viral , SARS-CoV-2
5.
EBioMedicine ; : 104330, 2022 Nov 08.
Article in English | MEDLINE | ID: covidwho-2298955

ABSTRACT

BACKGROUND: Co-encapsulated antiretrovirals (ARVs) with ingestible sensor (IS) has the capacity to monitor adherence in real-time using a sensor patch, a mobile device, and supporting software. We evaluated the acceptability, effectiveness, and sustainability of the IS system with real-time text reminders. METHODS: Participants were recruited from HIV clinics in Los Angeles and were randomised 1:1 to IS or usual care (UC) group. Adherence to ARVs (primary outcome) was measured by IS system (IS group only), plasma ARV concentration, and self-report. IS-measured adherence was clustered by group-based trajectory model and was validated by ARV concentration summarized by integrated pharmacokinetic adherence measure (IPAM) score. HIV RNA viral load (VL) was compared between IS and UC group. FINDINGS: A total of 112 (IS = 54, UC = 58) participants who completed baseline with at least one follow-up data collection were included in analyses. Overall satisfaction rate for the IS system was >90%. The IPAM score was higher (0.018, 95% CI: -0.098-0.134, p = 0.75) and VL decayed faster (-0.020, 95% CI: -0.042-0.002, p = 0.08) in the IS group compared with the UC group. The ingestible sensor system was well tolerated by study participants. INTERPRETATION: The IS system was well accepted by participants and its use was associated with improved adherence and lower HIV RNA VL. The findings provide a potentially effective strategy for improving adherence. FUNDING: This work was supported by grant R01-MH110056 from the National Institute of Mental Health (NIMH)/National Institutes of Health (NIH). Y. Wang was in part supported by the NIMH/NIH award T32MH080634. E. Daar was in part supported by the National Center for Advancing Translational Sciences through UCLACTSI Grant UL1TR001881. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

6.
Ann Intern Med ; 176(3): 348-354, 2023 03.
Article in English | MEDLINE | ID: covidwho-2256922

ABSTRACT

BACKGROUND: Although symptom and viral rebound have been reported after nirmatrelvir-ritonavir treatment, the trajectories of symptoms and viral load during the natural course of COVID-19 have not been well described. OBJECTIVE: To characterize symptom and viral rebound in untreated outpatients with mild to moderate COVID-19. DESIGN: Retrospective analysis of participants in a randomized, placebo-controlled trial. (ClinicalTrials.gov: NCT04518410). SETTING: Multicenter trial. PATIENTS: 563 participants receiving placebo in the ACTIV-2/A5401 (Adaptive Platform Treatment Trial for Outpatients With COVID-19) platform trial. MEASUREMENTS: Participants recorded the severity of 13 symptoms daily between days 0 and 28. Nasal swabs were collected for SARS-CoV-2 RNA testing on days 0 to 14, 21, and 28. Symptom rebound was defined as a 4-point increase in total symptom score after improvement any time after study entry. Viral rebound was defined as an increase of at least 0.5 log10 RNA copies/mL from the immediately preceding time point to a viral load of 3.0 log10 copies/mL or higher. High-level viral rebound was defined as an increase of at least 0.5 log10 RNA copies/mL to a viral load of 5.0 log10 copies/mL or higher. RESULTS: Symptom rebound was identified in 26% of participants at a median of 11 days after initial symptom onset. Viral rebound was detected in 31% and high-level viral rebound in 13% of participants. Most symptom and viral rebound events were transient, because 89% of symptom rebound and 95% of viral rebound events occurred at only a single time point before improving. The combination of symptom and high-level viral rebound was observed in 3% of participants. LIMITATION: A largely unvaccinated population infected with pre-Omicron variants was evaluated. CONCLUSION: Symptom or viral relapse in the absence of antiviral treatment is common, but the combination of symptom and viral rebound is rare. PRIMARY FUNDING SOURCE: National Institute of Allergy and Infectious Diseases.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Retrospective Studies , RNA, Viral
7.
Clin Infect Dis ; 2022 Oct 10.
Article in English | MEDLINE | ID: covidwho-2268903

ABSTRACT

Acute COVID-19 symptoms limit daily activities, but little is known about its association with SARS-CoV-2 viral burden. In this exploratory analysis of placebo recipients in the ACTIV-2/A5401 platform trial, we showed that high anterior nasal (AN) RNA levels and detectable plasma RNA were associated with delayed symptom improvement.

8.
J Clin Transl Sci ; 7(1): e23, 2023.
Article in English | MEDLINE | ID: covidwho-2239572

ABSTRACT

Introduction: Communities of color have faced disproportionate morbidity and mortality from COVID-19, coupled with historical underrepresentation in US clinical trials, creating challenges for equitable participation in developing and testing a safe and effective COVID-19 vaccine. Methods: To increase diversity, including racial and ethnic representation, in local Los Angeles County NIH-sponsored Phase 3 SARS-CoV-2 vaccine clinical trials, we used deliberative community engagement approaches to form a Community Consultant Panel (CCP) that partnered with trial research teams. Thirteen members were recruited, including expertise from essential workers, community-based and faith-based organizations, or leaders from racial and ethnic minority communities. Results: Working closely with local investigators for the vaccine studies, the CCP provided critical insight on best practices for community trust building, clinical trial participation, and reliable information dissemination regarding COVID-19 vaccines. Modifying recruitment, outreach, and trial protocols led to majority-minority participants (55%-78%) in each of the three vaccine clinical trials. CCP's input led to cultural tailoring of recruitment materials, changes in recruitment messaging, and supportive services to improve trial accessibility and acceptability (transportation, protocols for cultural competency, and support linkages to care in case of an adverse event). Barriers to clinical trial participation unable to be resolved included childcare, requests for after-hours appointment availability, and mobile locations for trial visits. Conclusion: Using deliberative community engagement can provide critical and timely insight into the community-centered barriers to COVID-19 vaccine trial participation, including addressing social determinants of health, trust, clinical trial literacy, structural barriers, and identifying trusted messenger and reliable sources of information.

10.
J Infect Dis ; 228(2): 133-142, 2023 Jul 14.
Article in English | MEDLINE | ID: covidwho-2212816

ABSTRACT

BACKGROUND: SAB-185, a novel fully human IgG polyclonal immunoglobulin product, underwent phase 2 evaluation for nonhospitalized adults with mild-moderate coronavirus disease 2019 (COVID-19). METHODS: Participants received intravenous SAB-185 3840 units/kg (low-dose) or placebo, or 10 240 units/kg (high-dose) or placebo. Primary outcome measures were nasopharyngeal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA < lower limit of quantification (LLOQ) at study days 3, 7, and 14, time to symptomatic improvement, and safety through day 28. RESULTS: Two-hundred thirteen participants received low-dose SAB-185/placebo (n = 107/106) and 215 high-dose SAB-185/placebo (n = 110/105). The proportions with SARS-CoV-2 RNA < LLOQ were higher for SAB-185 versus placebo at days 3 and 7 and similar at day 14, and significantly higher at day 7 for high-dose SAB-185 versus placebo only, relative risk 1.23 (95% confidence interval, 1.01-1.49). At day 3, SARS-CoV-2 RNA levels were lower with low-dose and high-dose SAB-185 versus placebo: differences in medians of -0.78 log10 copies/mL (P = .08) and -0.71 log10 copies/mL (P = .10), respectively. No difference was observed in time to symptom improvement: median 11/10 days (P = .24) for low-dose SAB-185/placebo and 8/10 days (P = .50) for high-dose SAB-185/placebo. Grade ≥3 adverse events occurred in 5%/13% of low-dose SAB-185/placebo and 9%/12% of high-dose SAB-185/placebo. CONCLUSIONS: SAB-185 was safe and generally well tolerated and demonstrated modest antiviral activity in predominantly low-risk nonhospitalized adults with COVID-19. Clinical Trials Registration. NCT04518410.


Subject(s)
COVID-19 , Adult , Humans , SARS-CoV-2 , Antiviral Agents/adverse effects , RNA, Viral , Immunoglobulin G , Double-Blind Method
11.
Open Forum Infect Dis ; 9(11): ofac618, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-2152129

ABSTRACT

Background: Identifying characteristics associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA shedding may be useful to understand viral compartmentalization, disease pathogenesis, and risks for viral transmission. Methods: Participants were enrolled August 2020 to February 2021 in ACTIV-2/A5401, a placebo-controlled platform trial evaluating investigational therapies for mild-to-moderate coronavirus disease 2019 (COVID-19), and underwent quantitative SARS-CoV-2 RNA testing on nasopharyngeal and anterior nasal swabs, oral wash/saliva, and plasma at entry (day 0, pretreatment) and days 3, 7, 14, and 28. Concordance of RNA levels (copies/mL) across compartments and predictors of nasopharyngeal RNA levels were assessed at entry (n = 537). Predictors of changes over time were evaluated among placebo recipients (n = 265) with censored linear regression models. Results: Nasopharyngeal and anterior nasal RNA levels at study entry were highly correlated (r = 0.84); higher levels of both were associated with greater detection of RNA in plasma and oral wash/saliva. Older age, White non-Hispanic race/ethnicity, lower body mass index (BMI), SARS-CoV-2 immunoglobulin G seronegativity, and shorter prior symptom duration were associated with higher nasopharyngeal RNA at entry. In adjusted models, body mass index and race/ethnicity associations were attenuated, but the association with age remained (for every 10 years older, mean nasopharyngeal RNA was 0.27 log10 copies/mL higher; P < .001). Examining longitudinal viral RNA levels among placebo recipients, women had faster declines in nasopharyngeal RNA than men (mean change, -2.0 vs -1.3 log10 copies/mL, entry to day 3; P < .001). Conclusions: SARS-CoV-2 RNA shedding was concordant across compartments. Age was strongly associated with viral shedding, and men had slower viral clearance than women, which could explain sex differences in acute COVID-19 outcomes.

12.
JCI Insight ; 2022 Nov 15.
Article in English | MEDLINE | ID: covidwho-2117617

ABSTRACT

Despite the widespread use of SARS-CoV-2-specific monoclonal antibody (mAb) therapy for the treatment of acute COVID-19, the impact of this therapy on the development of SARS-CoV-2-specific T cell responses has been unknown, resulting in uncertainty as to whether anti-SARS-CoV-2 mAb administration may result in failure to generate immune memory. Alternatively, it has been suggested that SARS-CoV-2-specific mAb may enhance adaptive immunity to SARS-CoV-2 via a "vaccinal effect." Bamlanivimab (Eli Lilly) is a recombinant human IgG1 that was granted FDA emergency use authorization for the treatment of mild to moderate COVID-19 in those at high risk for progression to severe disease. Here, we compared SARS-CoV-2 specific CD4+ and CD8+ T cell responses of 95 individuals from the ACTIV-2/A5401 clinical trial 28 days after treatment with 700 mg bamlanivimab versus placebo. SARS-CoV-2-specific T cell responses were evaluated using activation induced marker (AIM) assays in conjunction with intracellular cytokine staining. We demonstrate that most individuals with acute COVID-19 develop SARS-CoV-2-specific T cell responses. Overall, our findings suggest that the quantity and quality of SARS-CoV-2-specific T cell memory was robust in individuals who received bamlanivimab for acute COVID-19. Receipt of bamlanivimab during acute COVID-19 neither diminished nor enhanced SARS-CoV-2-specific cellular immunity.

13.
Nat Microbiol ; 7(11): 1906-1917, 2022 11.
Article in English | MEDLINE | ID: covidwho-2087227

ABSTRACT

SARS-CoV-2 mutations that cause resistance to monoclonal antibody (mAb) therapy have been reported. However, it remains unclear whether in vivo emergence of SARS-CoV-2 resistance mutations alters viral replication dynamics or therapeutic efficacy in the immune-competent population. As part of the ACTIV-2/A5401 randomized clinical trial (NCT04518410), non-hospitalized participants with symptomatic SARS-CoV-2 infection were given bamlanivimab (700 mg or 7,000 mg) or placebo treatment. Here¸ we report that treatment-emergent resistance mutations [detected through targeted Spike (S) gene next-generation sequencing] were significantly more likely to be detected after bamlanivimab 700 mg treatment compared with the placebo group (7% of 111 vs 0% of 112 participants, P = 0.003). No treatment-emergent resistance mutations among the 48 participants who received 7,000 mg bamlanivimab were recorded. Participants in which emerging mAb resistant virus mutations were identified showed significantly higher pretreatment nasopharyngeal and anterior nasal viral loads. Daily respiratory tract viral sampling through study day 14 showed the dynamic nature of in vivo SARS-CoV-2 infection and indicated a rapid and sustained viral rebound after the emergence of resistance mutations. Participants with emerging bamlanivimab resistance often accumulated additional polymorphisms found in current variants of concern/interest that are associated with immune escape. These results highlight the potential for rapid emergence of resistance during mAb monotherapy treatment that results in prolonged high-level respiratory tract viral loads. Assessment of viral resistance should be prioritized during the development and clinical implementation of antiviral treatments for COVID-19.


Subject(s)
COVID-19 Drug Treatment , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Antibodies, Monoclonal, Humanized/therapeutic use , Mutation , Antibodies, Monoclonal
14.
Mayo Clin Proc Innov Qual Outcomes ; 6(5): 484-487, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2049628

ABSTRACT

Although corticosteroid therapy is the standard of care for all patients hospitalized with severe coronavirus disease 2019 (COVID-19), the studies demonstrating the mortality-benefit ratio of corticosteroids were limited to fully evaluate their adverse effects. To determine the severity of corticosteroid-induced hyperglycemia in patients with and without diabetes mellitus, we retrospectively collected data from the medical records of patients hospitalized with COVID-19 before and after corticosteroids were the standard of care. Corticosteroid-induced hyperglycemia was more severe in patients hospitalized with COVID-19 with diabetes than those without diabetes. Additionally, patients with diabetes required higher doses of correctional insulin per day when on corticosteroid therapy, suggesting that intensive point-of-care glucose monitoring could be limited in patients without diabetes mellitus and support cautionary use of corticosteroids in patients with COVID-19 discharged with supplemental oxygen.

15.
Cell Rep Med ; 3(7): 100678, 2022 07 19.
Article in English | MEDLINE | ID: covidwho-2042205

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibodies (mAbs) are among the treatments recommended for high-risk ambulatory persons with coronavirus 2019 (COVID-19). Here, we study viral culture dynamics post-treatment in a subset of participants receiving the mAb bamlanivimab in the ACTIV-2 trial (ClinicalTrials.gov: NCT04518410). Viral load by qPCR and viral culture are performed from anterior nasal swabs collected on study days 0 (day of treatment), 1, 2, 3, and 7. Treatment with mAbs results in rapid clearance of culturable virus. One day after treatment, 0 of 28 (0%) participants receiving mAbs and 16 of 39 (41%) receiving placebo still have culturable virus (p < 0.0001). Recrudescence of culturable virus is detected in three participants with emerging mAb resistance and viral RNA rebound. While further studies are necessary to fully define the relationship between shed culturable virus and transmission, these results raise the possibility that mAbs may offer immediate (household) and public-health benefits by reducing onward transmission.


Subject(s)
COVID-19 Drug Treatment , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing , Humans , SARS-CoV-2
16.
Nat Commun ; 13(1): 4931, 2022 08 22.
Article in English | MEDLINE | ID: covidwho-2000888

ABSTRACT

Anti-SARS-CoV-2 monoclonal antibodies are mainstay COVID-19 therapeutics. Safety, antiviral, and clinical efficacy of bamlanivimab were evaluated in the randomized controlled trial ACTIV-2/A5401. Non-hospitalized adults were randomized 1:1 within 10 days of COVID-19 symptoms to bamlanivimab or blinded-placebo in two dose-cohorts (7000 mg, n = 94; 700 mg, n = 223). No differences in bamlanivimab vs placebo were observed in the primary outcomes: proportion with undetectable nasopharyngeal SARS-CoV-2 RNA at days 3, 7, 14, 21, and 28 (risk ratio = 0.82-1.05 for 7000 mg [p(overall) = 0.88] and 0.81-1.21 for 700 mg [p(overall) = 0.49]), time to symptom improvement (median 21 vs 18.5 days [p = 0.97], 7000 mg; 24 vs 20.5 days [p = 0.08], 700 mg), or grade 3+ adverse events. However, bamlanivimab was associated with lower day 3 nasopharyngeal viral levels and faster reductions in inflammatory markers and viral decay by modeling. This study provides evidence of faster reductions in nasopharyngeal SARS-CoV-2 RNA levels but not shorter symptom durations in non-hospitalized adults with early variants of SARS-CoV-2.


Subject(s)
COVID-19 Drug Treatment , Adult , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing , Antibodies, Viral , Antiviral Agents/therapeutic use , Humans , RNA, Viral , SARS-CoV-2
17.
N Engl J Med ; 385(25): 2348-2360, 2021 12 16.
Article in English | MEDLINE | ID: covidwho-1442847

ABSTRACT

BACKGROUND: The safety and efficacy of the AZD1222 (ChAdOx1 nCoV-19) vaccine in a large, diverse population at increased risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the United States, Chile, and Peru has not been known. METHODS: In this ongoing, double-blind, randomized, placebo-controlled, phase 3 clinical trial, we investigated the safety, vaccine efficacy, and immunogenicity of two doses of AZD1222 as compared with placebo in preventing the onset of symptomatic and severe coronavirus disease 2019 (Covid-19) 15 days or more after the second dose in adults, including older adults, in the United States, Chile, and Peru. RESULTS: A total of 32,451 participants underwent randomization, in a 2:1 ratio, to receive AZD1222 (21,635 participants) or placebo (10,816 participants). AZD1222 was safe, with low incidences of serious and medically attended adverse events and adverse events of special interest; the incidences were similar to those observed in the placebo group. Solicited local and systemic reactions were generally mild or moderate in both groups. Overall estimated vaccine efficacy was 74.0% (95% confidence interval [CI], 65.3 to 80.5; P<0.001) and estimated vaccine efficacy was 83.5% (95% CI, 54.2 to 94.1) in participants 65 years of age or older. High vaccine efficacy was consistent across a range of demographic subgroups. In the fully vaccinated analysis subgroup, no severe or critical symptomatic Covid-19 cases were observed among the 17,662 participants in the AZD1222 group; 8 cases were noted among the 8550 participants in the placebo group (<0.1%). The estimated vaccine efficacy for preventing SARS-CoV-2 infection (nucleocapsid antibody seroconversion) was 64.3% (95% CI, 56.1 to 71.0; P<0.001). SARS-CoV-2 spike protein binding and neutralizing antibodies increased after the first dose and increased further when measured 28 days after the second dose. CONCLUSIONS: AZD1222 was safe and efficacious in preventing symptomatic and severe Covid-19 across diverse populations that included older adults. (Funded by AstraZeneca and others; ClinicalTrials.gov number, NCT04516746.).


Subject(s)
COVID-19/prevention & control , ChAdOx1 nCoV-19 , Vaccine Efficacy , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/epidemiology , ChAdOx1 nCoV-19/adverse effects , Chile/epidemiology , Double-Blind Method , Female , Humans , Immunogenicity, Vaccine , Male , Middle Aged , Peru/epidemiology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , United States/epidemiology , Young Adult
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