Makers of successful COVID-19 vaccines wrestle with options for placebo recipients

Science ◽  
2020 ◽  
Author(s):  
Jon Cohen
Keyword(s):  
Placebo Recipients

scholarly journals Intrahost Dynamics of Human Cytomegalovirus Variants Acquired by Seronegative Glycoprotein B Vaccinees

2018 ◽  
Vol 93 (5) ◽  
Author(s):  
Cody S. Nelson ◽  
Diana Vera Cruz ◽  
Melody Su ◽  
Guanhua Xie ◽  
Nathan Vandergrift ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Rational Design ◽  
Hcmv Infection ◽  
Vaccine Trial ◽  
The United States ◽  
Glycoprotein B ◽  
Viral Population ◽  
Vaginal Fluid ◽  
The Impact ◽  
Placebo Recipients

ABSTRACTHuman cytomegalovirus (HCMV) is the most common congenital infection worldwide and a frequent cause of hearing loss and debilitating neurologic disease in newborn infants. Thus, a vaccine to prevent HCMV-associated congenital disease is a public health priority. One potential strategy is vaccination of women of child bearing age to prevent maternal HCMV acquisition during pregnancy. The glycoprotein B (gB) plus MF59 adjuvant subunit vaccine is the most efficacious tested clinically to date, demonstrating 50% protection against primary HCMV infection in a phase 2 clinical trial. Yet, the impact of gB/MF59-elicited immune responses on the population of viruses acquired by trial participants has not been assessed. In this analysis, we employed quantitative PCR as well as multiple sequencing methodologies to interrogate the magnitude and genetic composition of HCMV populations infecting gB/MF59 vaccinees and placebo recipients. We identified several differences between the viral dynamics in acutely infected vaccinees and placebo recipients. First, viral load was reduced in the saliva of gB vaccinees, though not in whole blood, vaginal fluid, or urine. Additionally, we observed possible anatomic compartmentalization of gB variants in the majority of vaccinees compared to only a single placebo recipient. Finally, we observed reduced acquisition of genetically related gB1, gB2, and gB4 genotype “supergroup” HCMV variants among vaccine recipients, suggesting that the gB1 genotype vaccine construct may have elicited partial protection against HCMV viruses with antigenically similar gB sequences. These findings suggest that gB immunization had a measurable impact on viral intrahost population dynamics and support future analysis of a larger cohort.IMPORTANCEThough not a household name like Zika virus, human cytomegalovirus (HCMV) causes permanent neurologic disability in one newborn child every hour in the United States, which is more than that for Down syndrome, fetal alcohol syndrome, and neural tube defects combined. There are currently no established effective measures to prevent viral transmission to the infant following HCMV infection of a pregnant mother. However, the glycoprotein B (gB)/MF59 vaccine, which aims to prevent pregnant women from acquiring HCMV, is the most successful HCMV vaccine tested clinically to date. Here, we used viral DNA isolated from patients enrolled in a gB vaccine trial who acquired HCMV and identified several impacts that this vaccine had on the size, distribution, and composition of thein vivoviral population. These results have increased our understanding of why the gB/MF59 vaccine was partially efficacious, and such investigations will inform future rational design of a vaccine to prevent congenital HCMV.

scholarly journals Hemagglutinin Stalk Antibody Responses Following Trivalent Inactivated Influenza Vaccine Immunization of Pregnant Women and Association With Protection From Influenza Virus Illness

2019 ◽  
Vol 71 (4) ◽  
pp. 1072-1079 ◽  
Author(s):  
Nisha Dhar ◽  
Gaurav Kwatra ◽  
Marta C Nunes ◽  
Clare Cutland ◽  
Alane Izu ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Pregnant Women ◽  
Influenza Virus Vaccine ◽  
H1n1 Influenza ◽  
Antibody Responses ◽  
Influenza B ◽  
Universal Vaccine ◽  
Lower Odds ◽  
Women Living With Hiv ◽  
Placebo Recipients

Abstract Background The conserved, immuno-subdominant influenza virus hemagglutinin (HA) stalk region is a potential universal group-specific influenza virus vaccine epitope. We analyzed antibody responses to H1 hemagglutinin stalk domain (H1/stalk) following trivalent influenza inactivated vaccine (IIV3) immunization in pregnant women, and association with protection against influenza virus illness. Methods One hundred forty-five human immunodeficiency virus (HIV)–uninfected pregnant women (68 IIV3 and 77 placebo recipients) and 140 pregnant women with HIV infection (72 IIV3 and 68 placebo recipients) were independently randomized in placebo-controlled efficacy trials of IIV3. Plasma samples were tested for H1/stalk immunoglobulin G (IgG) and hemagglutination inhibition (HAI) antibodies prevaccination and 1 month postvaccination. Women had weekly surveillance for influenza illness, confirmed by polymerase chain reaction. Results Increases in H1/stalk IgG (and HAI) antibody levels were elicited post-IIV3, with responses being higher in HIV-uninfected women than in women living with HIV. Among HIV-uninfected vaccinees, there was no correlation (postvaccination) between H1/stalk and HAI antibody responses, whereas a strong correlation was observed in vaccinees with HIV. The H1/stalk IgG concentration was lower among women developing A/H1N1 illness (85.3 arbitrary units [AU]/mL) than those without A/H1N1 illness (219.6 AU/mL; P = .001). H1/stalk IgG concentration ≥215 AU/mL was associated with 90% lower odds (odds ratio, 0.09; P = .005) of A/H1N1 illness. Also, H1/stalk IgG was significantly lower among women with influenza B illness (93.9 AU/mL) than among their counterparts (215.5 AU/mL) (P = .04); however, no association was observed after adjusting for HAI titers. Conclusions H1/stalk IgG concentration was associated with lower odds for A/H1N1 influenza virus illness, indicating its potential as an epitope for a universal vaccine against group 1 influenza virus.

scholarly journals Randomized, Controlled Human Challenge Study of the Safety, Immunogenicity, and Protective Efficacy of a Single Dose of Peru-15, a Live Attenuated Oral Cholera Vaccine

2002 ◽  
Vol 70 (4) ◽  
pp. 1965-1970 ◽  
Author(s):  
Mitchell B. Cohen ◽  
Ralph A. Giannella ◽  
Judy Bean ◽  
David N. Taylor ◽  
Susan Parker ◽  
...  
Keyword(s):  
Confidence Limit ◽  
Protective Efficacy ◽  
Oral Vaccine ◽  
Human Volunteer ◽  
Cholera Vaccine ◽  
Double Blind ◽  
Severe Diarrhea ◽  
Oral Cholera Vaccine ◽  
El Tor ◽  
Placebo Recipients

ABSTRACT Peru-15 is a live attenuated oral vaccine derived from a Vibrio cholerae O1 El Tor Inaba strain by a series of deletions and modifications, including deletion of the entire CT genetic element. Peru-15 is also a stable, motility-defective strain and is unable to recombine with homologous DNA. We wished to determine whether a single oral dose of Peru-15 was safe and immunogenic and whether it would provide significant protection against moderate and severe diarrhea in a randomized, double-blind, placebo-controlled human volunteer cholera challenge model. A total of 59 volunteers were randomly allocated to groups to receive either 2 × 108 CFU of reconstituted, lyophilized Peru-15 vaccine diluted in CeraVacx buffer or placebo (CeraVacx buffer alone). Approximately 3 months after vaccination, 36 of these volunteers were challenged with approximately 105 CFU of virulent V. cholerae O1 El Tor Inaba strain N16961, prepared from a standardized frozen inoculum. Among vaccinees, 98% showed at least a fourfold increase in vibriocidal antibody titers. After challenge, 5 (42%) of the 12 placebo recipients and none (0%) of the 24 vaccinees had moderate or severe diarrhea (≥3,000 g of diarrheal stool) (P = 0.002; protective efficacy, 100%; lower one-sided 95% confidence limit, 75%). A total of 7 (58%) of the 12 placebo recipients and 1 (4%) of the 24 vaccinees had any diarrhea (P < 0.001; protective efficacy, 93%; lower one-sided 95% confidence limit, 62%). The total number of diarrheal stools, weight of diarrheal stools, incidence of fever, and peak stool V. cholerae excretion among vaccinees were all significantly lower than in placebo recipients. Peru-15 is a well-tolerated and immunogenic oral cholera vaccine that affords protective efficacy against life-threatening cholera diarrhea in a human volunteer challenge model. This vaccine may therefore be a safe and effective tool to prevent cholera in travelers and is a strong candidate for further evaluation to prevent cholera in an area where cholera is endemic.

scholarly journals Safety and Immunogenicity of Single-Dose Live Oral Cholera Vaccine Strain CVD 103-HgR, Prepared from New Master and Working Cell Banks

2013 ◽  
Vol 21 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Wilbur H. Chen ◽  
Richard N. Greenberg ◽  
Marcela F. Pasetti ◽  
Sofie Livio ◽  
Michael Lock ◽  
...  
Keyword(s):  
United States ◽  
Single Dose ◽  
Cholera Toxin ◽  
Vaccine Strain ◽  
The United States ◽  
Cholera Vaccine ◽  
Oral Cholera Vaccine ◽  
Working Cell ◽  
Cell Banks ◽  
Placebo Recipients

ABSTRACTCurrently, no cholera vaccine is available for persons traveling from the United States to areas of high cholera transmission and who for reasons of occupation or host factors are at increased risk for development of the disease. A single-dose oral cholera vaccine with a rapid onset of protection would be particularly useful for such travelers and might also be an adjunct control measure for cholera outbreaks. The attenuatedVibrio choleraeO1 vaccine strain CVD 103-HgR harbors a 94% deletion of the cholera toxin A subunit gene (ctxA) and has a mercury resistance gene inserted in the gene encoding hemolysin A. We undertook a phase I randomized placebo-controlled two-site trial to assess the safety and immunogenicity of a preliminary formulation of CVD 103-HgR prepared from new master and working cell banks. Healthy young adults were randomized (5:1 vaccinees to placebo recipients) to receive a single oral dose of ∼4.4 × 108CFU of vaccine or a placebo. Blood serum vibriocidal and cholera toxin-specific IgG antibodies were measured before and 10, 14, and 28 days following vaccination or placebo. Excretion of the vaccine strain in the stool was assessed during the first week postvaccination. A total of 66 subjects were enrolled, comprising 55 vaccinees and 11 placebo recipients. The vaccine was well tolerated. The overall vibriocidal and anti-cholera toxin seroconversion rates were 89% and 57%, respectively. CVD 103-HgR is undergoing renewed manufacture for licensure in the United States under the auspices of PaxVax. Our data mimic those from previous commercial formulations that elicited vibriocidal antibody seroconversion (a correlate of protection) in ∼90% of vaccinees. (This study has been registered at ClinicalTrials.gov under registration no. NCT01585181.)

scholarly journals Genetic signatures of human cytomegalovirus variants acquired by seronegative glycoprotein B vaccinees

2018 ◽  
Author(s):  
Cody S. Nelson ◽  
Diana Vera Cruz ◽  
Melody Su ◽  
Guanhua Xie ◽  
Nathan Vandergrift ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Rational Design ◽  
Hcmv Infection ◽  
Vaccine Trial ◽  
The United States ◽  
Glycoprotein B ◽  
Viral Population ◽  
The Impact ◽  
Placebo Recipients

AbstractHuman cytomegalovirus (HCMV) is the most common congenital infection worldwide, and a frequent cause of hearing loss or debilitating neurologic disease in newborn infants. Thus, a vaccine to prevent HCMV-associated congenital disease is a public health priority. One potential strategy is vaccination of women of child-bearing age to prevent maternal HCMV acquisition during pregnancy. The glycoprotein B (gB) + MF59 adjuvant subunit vaccine is the most efficacious tested clinically to date, demonstrating approximately 50% protection against HCMV infection of seronegative women in multiple phase 2 trials. Yet, the impact of gB/MF59-elicited immune responses on the population of viruses acquired by trial participants has not been assessed. In this analysis, we employed quantitative PCR as well as multiple sequencing methodologies to interrogate the magnitude and genetic composition of HCMV populations infecting gB/MF59 vaccinees and placebo recipients. We identified several differences between the viral dynamics of acutely-infected vaccinees and placebo recipients. First, there was reduced magnitude viral shedding in the saliva of gB vaccinees. Additionally, employing a panel of tests for genetic compartmentalization, we noted tissue-specific gB haplotypes in the majority of vaccinees though only in a single placebo recipient. Finally, we observed reduced acquisition of genetically-related gB1, gB2, and gB4 genotype “supergroup” HCMV variants among vaccine recipients, suggesting that the gB1 genotype vaccine construct may have elicited partial protection against HCMV viruses with antigenically-similar gB sequences. These findings indicate that gB immunization may have had a measurable impact on viral intrahost population dynamics and support future analysis of a larger cohort.Author SummaryThough not a household name like Zika virus, human cytomegalovirus (HCMV) causes permanent neurologic disability in one newborn child every hour in the United States - more than Down syndrome, fetal alcohol syndrome, and neural tube defects combined. There are currently no established effective preventative measures to inhibit congenital HCMV transmission following acute or chronic HCMV infection of a pregnant mother. However, the glycoprotein B (gB) vaccine is the most effective HCMV vaccine tried clinically to date. Here, we utilized high-throughput, next-generation sequencing of viral DNA isolated from patients enrolled in a gB vaccine trial, and identified several impacts that this vaccine had on the size, distribution, and composition of thein vivoviral population. These results have increased our understanding of why the gB/MF59 vaccine was partially efficacious and will inform future rational design of a vaccine to prevent congenital HCMV.

scholarly journals Efficacy and Safety of NVX-CoV2373 in Adults in the United States and Mexico

2021 ◽  
Author(s):  
Lisa M. Dunkle ◽  
Karen L. Kotloff ◽  
Cynthia L. Gay ◽  
German Anez ◽  
Jeffrey M. Adelglass ◽  
...  
Keyword(s):  
United States ◽  
Controlled Trial ◽  
The United States ◽  
Efficacy And Safety ◽  
Serious Adverse Events ◽  
S Protein ◽  
Viral Genomes ◽  
The United Kingdom ◽  
To Receive ◽  
Placebo Recipients

BACKGROUND Vaccination using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein antigen has been effective in the prevention of coronavirus disease 2019 (Covid-19). NVX-CoV2373 is an adjuvanted, recombinant S protein nanoparticle vaccine that demonstrated clinical efficacy for prevention of Covid-19 in phase 2b/3 trials in the United Kingdom and South Africa. METHODS This phase 3, randomized, observer-blinded, placebo-controlled trial evaluated the efficacy and safety of NVX-CoV2373 in adults ≥18 years of age in the United States and Mexico during the first quarter of 2021. Participants were randomized in a 2:1 ratio to receive two doses of NVX-CoV2373 or placebo 21 days apart. The primary end point was vaccine efficacy (VE) against reverse transcriptase-polymerase chain reaction-confirmed Covid-19 in SARS-CoV-2-naive participants ≥7 days after the second dose administration. RESULTS Of the 29,949 participants randomized between December 27, 2020, and February 18, 2021, 29,582 (median age: 47 years, 12.6% ≥65 years) received ≥1 dose: 19,714 received vaccine and 9868 placebo. In the per-protocol population, there were 77 Covid-19 cases; 14 among vaccine and 63 among placebo recipients (VE: 90.4%, 95% confidence interval [CI] 82.9 to 94.6, P<0.001). All moderate-to-severe cases occurred in placebo recipients, yielding VE of 100% (95% CI 87.0 to 100). Most sequenced viral genomes (48/61, 78.7%) were variants of concern (VOC) or interest (VOI), mainly represented by variant alpha/B.1.1.7 (31/35, 88.6% VOC identified). VE against any VOC/VOI was 92.6% (95% CI 83.6 to 96.7). Reactogenicity was mostly mild-to-moderate and transient, but more frequent in NVX-CoV2373 recipients and after the second dose. Serious adverse events were rare and evenly distributed between treatments. CONCLUSIONS NVX-CoV2373 was well tolerated and demonstrated a high overall VE (>90%) for prevention of Covid-19, with most cases due to variant strains. (Funded by the Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority and the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health; PREVENT-19 ClinicalTrials.gov number, NCT04611802.)

scholarly journals Randomized, Double-Blind, Placebo-Controlled, Multicentered Trial of the Efficacy of a Single Dose of Live Oral Cholera Vaccine CVD 103-HgR in Preventing Cholera following Challenge with Vibrio cholerae O1 El Tor Inaba Three Months after Vaccination

1999 ◽  
Vol 67 (12) ◽  
pp. 6341-6345 ◽  
Author(s):  
Carol O. Tacket ◽  
Mitchell B. Cohen ◽  
Steven S. Wasserman ◽  
Genevieve Losonsky ◽  
Sofie Livio ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Protective Efficacy ◽  
Mercury Resistance ◽  
Cholera Vaccine ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Oral Cholera Vaccine ◽  
K 12 ◽  
El Tor ◽  
Placebo Recipients

ABSTRACT CVD 103-HgR is a live oral cholera vaccine strain constructed by deleting 94% of the gene for the enzymatically active A subunit of cholera toxin from classical Inaba Vibrio cholerae O1 569B; the strain also contains a mercury resistance gene as an identifying marker. This vaccine was well tolerated and immunogenic in double-blind, controlled studies and was protective in open-label studies of volunteers challenged with V. cholerae O1. A randomized, double-blind, placebo-controlled, multicenter study of vaccine efficacy was designed to test longer-term protection of CVD 103-HgR against moderate and severe El Tor cholera in U.S. volunteers. A total of 85 volunteers (50 at the University of Maryland and 35 at Children's Hospital Medical Center/University of Cincinnati) were recruited for vaccination and challenge with wild-type V. cholerae El Tor Inaba. Volunteers were randomized in a double-blind manner to receive, with buffer, a single oral dose of either CVD 103-HgR (2 × 108to 8 × 108 CFU) or placebo (killed E. coli K-12). About 3 months after immunization, 51 of these volunteers were orally challenged with 105 CFU of virulent V. cholerae O1 El Tor Inaba strain N16961, prepared from a standardized frozen inoculum. Ninety-one percent of the vaccinees had a ≥4-fold rise in serum vibriocidal antibodies after vaccination. After challenge, 9 (39%) of the 23 placebo recipients and 1 (4%) of the 28 vaccinees had moderate or severe diarrhea (≥3-liter diarrheal stool) (P < 0.01; protective efficacy, 91%). A total of 21 (91%) of 23 placebo recipients and 5 (18%) of 28 vaccinees had any diarrhea (P < 0.001; protective efficacy, 80%). Peak stoolV. cholerae excretion among placebo recipients was 1.1 × 107 CFU/g and among vaccinees was 4.9 × 102 CFU/g (P < 0.001). This vaccine could therefore be a safe and effective tool to prevent cholera in travelers.

scholarly journals Efficacy and serious adverse events profile of the adjuvanted recombinant zoster vaccine in adults with pre-existing potential immune-mediated diseases: a pooled post hoc analysis on two parallel randomized trials

Rheumatology ◽  
2020 ◽  
Author(s):  
Alemnew F Dagnew ◽  
Debora Rausch ◽  
Caroline Hervé ◽  
Toufik Zahaf ◽  
Myron J Levin ◽  
...  
Keyword(s):  
Adverse Events ◽  
Age Groups ◽  
Zoster Vaccine ◽  
Post Dose ◽  
Serious Adverse Events ◽  
Post Hoc Analysis ◽  
Immune Mediated ◽  
Recombinant Zoster Vaccine ◽  
Post Hoc ◽  
Placebo Recipients

Abstract Objective In the ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials, the adjuvanted recombinant zoster vaccine (RZV) demonstrated ≥90% efficacy in preventing herpes zoster (HZ) in all age groups ≥50 years. Given the increased HZ risk associated with certain underlying autoimmune diseases or their treatment regimes, we conducted a post hoc analysis of RZV’s efficacy against HZ and safety profile [specifically, the occurrence of serious adverse events (SAEs)] in ZOE-50/70 participants who reported pre-existing potential immune-mediated diseases (pIMDs) at enrolment and were not on immunosuppressive therapies. Methods Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomized to receive two doses of RZV or placebo 2 months apart. In this subgroup analysis of participants with at least one pIMD at enrolment, the efficacy was calculated for two-dose recipients who did not develop confirmed HZ before 30 days post-dose 2. SAE occurrence was evaluated for all participants who received at least one dose. Results Of the 14 645 RZV and 14 660 placebo recipients from the ZOE-50/70 studies, 983 and 960, respectively, reported at least one pre-existing pIMD at enrolment and were included in these analyses. The most frequent pre-existing conditions were psoriasis, spondyloarthropathy and RA. Efficacy against HZ was 90.5% (95% CI: 73.5, 97.5%) overall with the lowest being 84.4% (95% CI: 30.8, 98.3%) in the 70–79-year-old age group. SAEs and fatal SAEs were similar between RZV and placebo recipients. Conclusion In ZOE-50/70 participants with pre-existing pIMDs, RZV was highly efficacious against HZ and SAE incidence was similar between RZV and placebo recipients. Trial registration ClinicalTrials.gov, https://clinicaltrials.gov, NCT01165177 (ZOE-50), NCT01165229 (ZOE-70).

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