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10,192 result(s) for "Scott, Daniel A."
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Phase 1 trial of a 20-valent pneumococcal conjugate vaccine in healthy adults
Streptococcus pneumoniae is a leading cause of bacteremia, bacterial pneumonia, and meningitis, and is associated with substantial morbidity and mortality, particularly in those under 2 years of age and those over 65 years of age. While significant progress against S. pneumoniae-related disease has been made as a result of the introduction of pneumococcal conjugate vaccines (PCV7, PCV10 and PCV13), there remains value in further expanding pneumococcal vaccine serotype coverage. Here we present the first report of a 20-valent pneumococcal conjugate vaccine (PCV20) containing capsular polysaccharide conjugates present in PCV13 as well as 7 new serotypes (8, 10A, 11A, 12F, 15B, 22F, and 33F) which are important contributors to pneumococcal disease. This Phase I first-in-human study was a randomized, controlled, observer-blinded study with a two-arm parallel design to assess the safety, tolerability, and immunogenicity of PCV20 in adults. A total of 66 healthy adults 18–49 years of age with no history of pneumococcal vaccination were enrolled and randomized to receive a single dose of PCV20 or a licensed tetanus, diphtheria, acellular pertussis combination vaccine (Tdap) control. Local injection site reactions, select systemic symptoms, laboratory studies, and adverse events were assessed. Opsonophagocytic activity (OPA) titers and IgG concentrations were measured in sera collected prior to, and approximately one month (28–35 days) after vaccination. Vaccination with PCV20 elicited substantial IgG and functional bactericidal immune responses as demonstrated by increases in IgG geometric mean concentrations (GMCs) and OPA geometric mean titers (GMTs) to the 20 vaccine serotypes. The overall safety profile of PCV20 was similar to Tdap, and generally consistent with that observed after PCV13 administration. Vaccination with PCV20 was well tolerated and induced substantial functional (OPA) and IgG responses to all vaccine serotypes. There were no safety issues identified in this Phase 1 study, and the data supported further evaluation of PCV20.
Comparative Immunogenicity and Efficacy of 13-Valent and 7-Valent Pneumococcal Conjugate Vaccines in Reducing Nasopharyngeal Colonization: A Randomized Double-Blind Trial
Background. The 13-valent pneumococcal conjugate vaccine (PCV13) was licensed to replace the 7-valent pneumococcal conjugate vaccine (PCV7) based on serological noninferiority criteria. To date no randomized PCV13 pediatric trial has included clinical endpoints. Methods. This randomized double-blind trial compared the impact of PCV13 versus PCV7 on nasopharyngeal (NP) colonization and immunogenicity. Healthy infants were randomized (1:1) to receive PCV7 or PCV13 at ages 2, 4, 6, and 12 months; NP swabs were collected at 2, 4, 6, 7, 12, 13, 18, and 24 months, and blood was drawn at 7 and 13 months. Rates of NP acquisition and prevalence, and serotype-specific immunoglobulin G (IgG) concentrations were assessed. Results. The per protocol analysis population included 881 PCV13 and 873 PCV7 recipients. PCV13 significantly reduced NP acquisition of the additional PCV13 serotypes 1, 6A, 7F, and 19A; the cross-reacting serotype 6C; and the common PCV7 serotype 19F. For serotype 3, and the other PCV7 serotypes, there were no significant differences between the vaccine groups. There were too few serotype 5 events to draw inference. The impact on prevalence at predefined time points was similar to that observed with NP acquisition. PCV13 elicited significantly higher IgG responses for PCV13 additional serotypes and serotype 19F, and similar or lower responses for 6/7 PCV7 serotypes. Conclusions. PCV13 resulted in lower acquisition and prevalence of NP colonization than PCV7 did for 4 additional PCV13 serotypes, and serotypes 6C and 19F. It was comparable with PCV7 for all other common serotypes. These findings predict vaccine effectiveness through both direct and indirect protection. Clinical Trials Registration. NCT00508742.
Immunogenicity and safety of a 13-valent pneumococcal conjugate vaccine compared to a 23-valent pneumococcal polysaccharide vaccine in pneumococcal vaccine-naive adults
•Pneumococcal conjugate vaccines elicit effective T cell dependent responses.•Conjugate and free polysaccharide vaccines were compared in older adults.•Conjugate responses were significantly greater for majority of serotypes.•Conjugate vaccine could provide enhanced immunity against pneumococcal disease. Streptococcus pneumoniae is a major cause of morbidity and mortality among adults 50 years of age and older in the United States. Pneumococcal conjugate vaccines are efficacious against pneumococcal disease in children and may also offer advantages in adults. We performed a randomized, modified double-blind trial that compared a single dose of 13-valent pneumococcal conjugate vaccine (PCV13) with 23-valent pneumococcal polysaccharide vaccine (PPSV23) in 831 pneumococcal vaccine naive adults 60–64 years of age. An additional group of 403 adults 50–59 years of age received open-label PCV13. Anti-pneumococcal opsonophagocytic activity (OPA) titers were measured at baseline, and at 1 month and 1 year after vaccination. In the randomized trial, the month 1 post-vaccination OPA geometric mean titers in the PCV13 group were statistically significantly higher than in the PPSV23 group for 8 of the 12 serotypes common to both vaccines and for serotype 6A, a serotype unique to PCV13, and were comparable for the other 4 common serotypes. The immune response to PCV13 was generally greater in adults 50–59 years of age compared to adults 60–64 years of age. OPA titers declined from 1 month to 1 year after PCV13 administration but remained higher than pre-vaccination baseline titers. PCV13 induces a greater functional immune response than PPSV23 for the majority of serotypes covered by PCV13, suggesting that PCV13 could offer immunological advantages over PPSV23 for prevention of vaccine-type pneumococcal infection.
Immunogenicity, Safety, and Tolerability of 13-Valent Pneumococcal Conjugate Vaccine Followed by 23-Valent Pneumococcal Polysaccharide Vaccine in Recipients of Allogeneic Hematopoietic Stem Cell Transplant Aged ≥2 Years: An Open-Label Study
Background. Life-threatening Streptococcus pneumoniae infections often occur after hematopoietic stem cell transplant (HSCT); vaccination is important for prevention. Methods. In an open-label study, patients (n = 251) 3–6 months after allogeneic HSCT received 3 doses of 13-valent pneumococcal conjugate vaccine (PCV13) at 1-month intervals, a fourth dose 6 months later, and 1 dose of 23-valent pneumococcal polysaccharide vaccine (PPSV23) 1 month later. Immunogenicity at prespecified time points and vaccine safety were assessed. Results. In the evaluable immunogenicity population (N = 216; mean age, 37.8 years), geometric mean fold rises (GMFRs) of immunoglobulin G geometric mean concentrations from baseline to postdose 3 showed significant increases in antibody levels across all PCV13 serotypes (GMFR range, 2.99–23.85; 95% confidence interval lower limit, >1); there were significant declines over the next 6 months, significant increases from predose 4 to postdose 4 (GMFR range, 3.00–6.97), and little change after PPSV23 (GMFR range, 0.86–1.12). Local and systemic reactions were more frequent after dose 4. Six patients experienced serious adverse events possibly related to PCV13 (facial diplegia, injection-site erythema and pyrexia, autoimmune hemolytic anemia, and suspected lack of vaccine efficacy after dose 3 leading to pneumococcal infection), PCV13 and PPSV23 (Guillain-Barré syndrome), or PPSV23 (cellulitis). There were 14 deaths, none related to study vaccines. Conclusions. A 3-dose PCV13 regimen followed by a booster dose may be required to protect against pneumococcal disease in HSCT recipients. Dose 4 was associated with increased local and systemic reactions, but the overall safety profile of a 4-dose regimen was considered acceptable. Clinical Trials Registration. NCT00980655.
Impact of the COVID-19 pandemic lockdown on public sector ophthalmic work by New Zealand’s ophthalmologists
Assesses the impact of the COVID-19 lockdown on New Zealand’s public ophthalmology service by measuring the reduction in elective clinic and elective operating volumes as well as the personal health impact for New Zealand ophthalmologists. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
Traveler's Diarrhea in Thailand: Randomized, Double-Blind Trial Comparing Single-Dose and 3-Day Azithromycin-Based Regimens with a 3-Day Levofloxacin Regimen
Background.Traveler's diarrhea in Thailand is frequently caused by Campylobacter jejuni. Rates of fluoroquinolone (FQ) resistance in Campylobacter organisms have exceeded 85% in recent years, and reduced fluoroquinolone efficacy has been observed. Methods.Azithromycin regimens were evaluated in a randomized, double-blind trial of azithromycin, given as a single 1-g dose or a 3-day regimen (500 mg daily), versus a 3-day regimen of levofloxacin (500 mg daily) in military field clinics in Thailand. Outcomes included clinical end points (time to the last unformed stool [TLUS] and cure rates) and microbiological end points (pathogen eradication). Results.A total of 156 patients with acute diarrhea were enrolled in the trial. Campylobacter organisms predominated (in 64% of patients), with levofloxacin resistance noted in 50% of Campylobacter organisms and with no azithromycin resistance noted. The cure rate at 72 h after treatment initiation was highest (96%) with single-dose azithromycin, compared with the cure rates of 85% noted with 3-day azithromycin and 71% noted with levofloxacin (P = .002). Single-dose azithromycin was also associated with the shortest median TLUS (35 h; P = .03, by log-rank test). Levofloxacin's efficacy was inferior to azithromycin's efficacy, except in patients with no pathogen identified during the first 24 h of treatment or in patients with levofloxacin-susceptible Campylobacter isolates, in whom it appeared to be equal to azithromycin. The rate of microbiological eradication was significantly better with azithromycin-based regimens (96%–100%), compared with levofloxacin (38%) (P = .001); however, this finding was poorly correlated with clinical outcome. A higher rate of posttreatment nausea in the 30 min after receipt of the first dose (14% vs. <6%; P = .06) was observed as a mild, self-limited complaint associated with single-dose azithromycin. Conclusions.Single-dose azithromycin is recommended for empirical therapy of traveler's diarrhea acquired in Thailand and is a reasonable first-line option for empirical management in general.
Prefusion F Protein–Based Respiratory Syncytial Virus Immunization in Pregnancy
Respiratory syncytial virus is a major cause of illness in infants. In this randomized, double-blind, placebo-controlled trial, the safety and immunogenicity of a bivalent RSV prefusion F protein–based vaccine was assessed in pregnant women and their infants. Anti-RSV antibodies were elicited with efficient transplacental transfer.
Vaccine Efficacy in Adults in a Respiratory Syncytial Virus Challenge Study
A human challenge model of RSV was used to assess the safety and immunogenicity of a bivalent RSV prefusion F protein–based vaccine against RSV infection. This vaccine construct has been advanced to further clinical testing.
A trial to evaluate the safety and immunogenicity of a 20-valent pneumococcal conjugate vaccine in populations of adults ≥65 years of age with different prior pneumococcal vaccination
•A phase 3 study in adults ≥65 years of age with prior pneumococcal vaccination.•Safety and immunogenicity of PCV20 were described in this population.•PCV20 safety and tolerability were similar across different vaccine histories.•PCV20 induced immune responses to all vaccine serotypes regardless of prior vaccine. A 20-valent pneumococcal conjugate vaccine, PCV20, was developed to expand protection against vaccine-preventable pneumococcal disease. PCV20 contains the components of the 13-valent pneumococcal conjugate vaccine, PCV13, and includes capsular polysaccharide conjugates for 7 additional serotypes. Thus, PCV20 may cover those additional serotypes in individuals previously vaccinated with PCV13 or provide benefits of immunization with a conjugate vaccine to individuals previously immunized with a pneumococcal polysaccharide vaccine. This study described the safety and immunogenicity of PCV20 in adults ≥65 years of age with prior pneumococcal vaccination. This phase 3, multicenter, randomized, open-label study was conducted in the United States and Sweden. Adults ≥65 years of age were enrolled into 1 of 3 cohorts based on their prior pneumococcal vaccination history (23-valent pneumococcal polysaccharide vaccine [PPSV23], PCV13, or both PCV13 and PPSV23). Participants were randomized 2:1 within their cohort to receive a single dose of PCV20 or PCV13 in those with prior PPSV23 only, and PCV20 or PPSV23 in those with prior PCV13 only; all participants with prior PCV13 and PPSV23 received PCV20. Safety was assessed by prompted local reactions within 10 days, systemic events within 7 days, adverse events (AEs) within 1 month, and serious AEs (SAEs) and newly diagnosed chronic medical conditions (NDCMCs) within 6 months after vaccination. Immune responses 1 month after PCV20 were assessed. The percentages of participants reporting local reactions, systemic events, and AEs after PCV20 administration were similar across cohorts and comparable with the PCV13 and PPSV23 control groups. SAE and NDCMC rates were low in all groups. Robust immune responses, including opsonophagocytic antibody responses, to the 20 vaccine serotypes were observed 1 month after PCV20 regardless of prior pneumococcal vaccination. PCV20 was well tolerated and immunogenic in adults ≥65 years of age previously vaccinated with different pneumococcal vaccine regimens. Clinicaltrials.gov NCT03835975.
A phase 3, randomized, double-blind study to evaluate the immunogenicity and safety of 3 lots of 20-valent pneumococcal conjugate vaccine in pneumococcal vaccine-naive adults 18 through 49 years of age
•This was a phase 3 randomized, double-blind PCV20 study in adults 18–49 years old.•The immunogenicity of 3 PCV20 lots was evaluated and safety of PCV20 was described.•Equivalence of vaccine responses was observed for 20 serotypes across 3 PCV20 lots.•All of the PCV20 lots elicited robust immune responses to the vaccine serotypes.•Safety and tolerability of PCV20 was acceptable and similar to PCV13. Introduction of pneumococcal conjugate vaccines (PCVs), including the 13-valent PCV (PCV13), has considerably reduced pneumococcal disease burden. However, additional serotypes not in PCV13 continue to present a substantial disease burden. The 20-valent PCV (PCV20) was developed to expand protection against pneumococcal disease beyond PCV13. As part of the phase 3 clinical development program, the current study assessed consistency of immune responses across 3 lots of PCV20 and described the safety profile of PCV20. This phase 3, randomized, multicenter, double-blind study of pneumococcal vaccine-naive adults 18–49 years of age randomized 1710 participants in a 2:2:2:1 ratio to receive 1 of 3 lots of PCV20 or PCV13. Immunogenicity was assessed through serotype-specific opsonophagocytic activity (OPA) titers before and approximately 1 month (28–42 days) after vaccination. Reported local reactions within 10 days, systemic events within 7 days, adverse events (AEs) within 30 days, and serious AEs (SAEs) and newly diagnosed chronic medical conditions (NDCMCs) within 6 months after vaccination were evaluated. Equivalence in immune responses (OPA geometric mean titers) for all 20 vaccine serotypes was demonstrated across the 3 PCV20 lots. Robust responses, assessed by OPA geometric mean fold rises, percentage of participants achieving ≥4-fold rises, and percentage of participants with OPA titers ≥lower limit of quantitation, were observed after PCV20. Reported rates of local reactions, systemic events, and AEs were similar between the pooled PCV20 lots and PCV13; most events were mild or moderate. Reported rates of SAEs and NDCMCs were low and similar between the PCV20 and PCV13 groups. Three different lots of PCV20 demonstrated robust and consistent immunogenicity. The safety and tolerability of PCV20 was acceptable and similar to that of PCV13. (Clinicaltrials.gov: NCT03828617).