Single Intramuscular Dose Research Articles

Capvaxive (V116): A new frontier in the prevention of pneumococcal pneumonia and invasive disease

Pneumococcal Pneumonia (PP) and Invasive Pneumococcal Disease (IPD), both highly contribute to the rate of morbidity and mortality in adults around the globe. They are caused by the bacteria called Streptococcus pneumoniae. According to a population-based study, the Global Incidence Rate of PP cases was 90.7 per 100,000 person-years, with a 7.6% case-fatality rate [1]. For adults Pneumococcal Conjugate Vaccines (PCVs), mainly PCV15 and PCV 20, along with Pneumococcal polysaccharide vaccine (PPSV23) are currently recommended by the Centers for Disease Control and Prevention. Among these already vaccines, arises Capvaxive (V116) by Merck for active immunization for the prevention of PP and IPD. Capvaxive, also known as pneumococcal 21-conjugate vaccine recently approved by the FDA for active immunization for prevention of pneumonia and invasive disease caused by 21 different serotypes of streptococcus pneumoniae in adults [2]. It is administered as a single intra-muscular dose of 0.5 ml. It stimulates the body's immune response by antigenic stimulation, leading to opsonophagocytic activity [OPA] against invasive S. Pneumoniae. It is known to induce OPA by activation of macrophages and neutrophils for engulfment and phagocytosis of bacterial cells [3]. Multiple trials have been conducted all over the world as reported to understand the safety, tolerability, and immunogenicity. Studies conducted resulted in non-inferiority to its comparator PPSV23 [4,5], encouraging its development for safety against S. Pneumoniae. Neither of the studies reported vaccine-related serious adverse effects or deaths. The most common adverse effect reported was solicited infusion site reaction, reported in up to 73% of participants [4]. When compared, Capvaxive infused participants had a higher antibody titer and induced immune response against all 21 serotypes, with a similar safety profile to its comparators. It notably had a more immunogenic reaction against the 9 unique serotypes, previously not targeted in PPSV23 [4]. As the newly FDA approved vaccine enters the market, it is crucial to keep track of its safety and tolerability as it reaches a wider population. It is a notable landmark of pharmacology to target 21 variants of S. Pneumonia which has been proved to be lethal in the past as it causes mortal pneumonia. As reported to have low levels of systemic side effects on patients infused with this vaccine, this is a step forward in encountering the deadly S. Pneumonia with more than 100 serotypes known to man.

Safety and immunogenicity of an acellular pertussis vaccine containing genetically detoxified pertussis toxin administered to pregnant women living with and without HIV and their newborns (WoMANPOWER): a randomised controlled trial in Uganda.

Immunisation in pregnancy against pertussis can reduce severe disease in infancy. There are few data on the safety and immunogenicity of vaccines given to pregnant women living with HIV and their infants. We aimed to describe the safety and immunogenicity of a tetanus-diphtheria-acellular pertussis (TdaP) vaccine containing genetically detoxified pertussis toxin given to pregnant women living with HIV and the effect of the vaccine on infant whole-cell pertussis vaccine responses. We conducted an observer-blind, randomised, phase 2, multicentre, non-inferiority trial evaluating safety and immunogenicity of a vaccine containing genetically detoxified acellular pertussis in pregnant women living with HIV in Uganda. Women aged at least 18 years between 16 weeks and 26 weeks of gestation were randomly assigned to receive the tetanus-diphtheria (Td) vaccine or TdaP vaccine. Stratified block randomisation using blocks of four with a 1:1:1:1 ratio stratified by participant HIV status was used to distribute participants into equal groups (50 participants per group for a total of 200 participants). The intervention was a 0·5 mL single intramuscular dose of TdaP vaccine. Td or TdaP vaccination was randomly assigned to different clinic days using randomisation software. Primary immunogenicity endpoints were anti-pertussis toxin and anti-filamentous haemagglutinin IgG concentrations in infants at delivery and 18 weeks following three doses of a whole-cell pertussis containing vaccine. This study is registered at ClinicalTrials.gov, NCT04589312. Between Oct 28, 2020, and May 21, 2021, 438 pregnant women were screened and 181 were randomly assigned: 90 to TdaP vaccine (40 HIV-positive participants and 50 HIV-negative participants) and 91 to Td vaccine (41 HIV-positive participants and 50 HIV-negative participants). All participants received Td, and 4 weeks later, 177 received either Td or TdaP. 32 serious adverse events occurred, none related to the study vaccine. At delivery, anti-pertussis toxin IgG concentrations for TdaP versus Td were superior in infants who were HIV-exposed but uninfected (geometric mean ratio 9·61, 95% CI 5·21-17·74) and HIV-unexposed infants (21·6, 11·2-41·7). In infants at 18 weeks, anti-pertussis toxin IgG concentrations for TdaP versus Td-vaccinated mothers were significantly lower for both infants who were HIV-exposed but uninfected (0·19, 0·09-0·43) and infants who were not HIV-exposed (0·17, 0·08-0·33). Serum bactericidal antibody generation following whole-cell pertussis vaccination in infants was not affected. TdaP was safe and immunogenic in pregnant women living with HIV and their infants. TdaP provided superior anti-pertussis toxin IgG concentrations at delivery. Following routine vaccination with whole-cell pertussis vaccine, infants born to women receiving the TdaP vaccine had lower anti-pertussis toxin IgG concentrations than infants born to women receiving Td. In the absence of a correlate of protection against pertussis disease, the clinical significance of this finding is unclear. Medical Research Council Joint Clinical Trials, Canadian Institutes of Health Research, and British Columbia Children's Hospital Research Institute.

Evaluation of Safety, Immunogenicity and Cross-Reactive Immunity of OVX836, a Nucleoprotein-Based Universal Influenza Vaccine, in Older Adults.

Background/Objectives: In a Phase 2a, double-blind, placebo-controlled study including healthy participants aged 18-55 years, OVX836, a nucleoprotein (NP)-based candidate vaccine, previously showed a good safety profile, a robust immune response (both humoral and cellular) and a preliminary signal of protection (VE = 84%) against PCR-confirmed symptomatic influenza after a single intramuscular dose of 180 µg, 300 µg or 480 µg. Methods: Using the same methodology, we confirmed the good safety and strong immunogenicity of OVX836 at the same doses in older adults (≥65 years), a key target population for influenza vaccination. Results: Significant humoral (anti-NP IgG) and cellular (interferon gamma (IFNγ) spot-forming cells per million peripheral blood mononuclear cells and specific CD4+ IFNγ+ T-cells) immune responses were observed at the three dose levels, without clear dose-response relationship. T-cell responses were shown to be highly cross-reactive against various influenza A strains, both seasonal and highly pathogenic avian strains. We also evaluated the effect of sex (stronger immune response in females) and age (stronger immune response in young adults) on the immune response to OVX836 after adjustment based on the pre-vaccination immune status. Conclusions: The results obtained with OVX836 lay the groundwork for a future placebo-controlled, field proof of concept efficacy Phase 2b trial.

Exploratory analysis of the economically justifiable price of tezepelumab for asthma severe in Colombia

Introduction Asthma severe imposes important economic burden on health systems, especially with the incorporation of new drugs. Recently, tezepelumab has been approved to prevent exacerbations in patients. This study explores the economically justifiable price of tezepelumab for preventing exacerbations in patients with severe asthma. Materials and methods A static model was developed using the decision tree microsimulation to estimate the quality-adjusted life years of two interventions: a single intramuscular dose of tezepelumab versus not applying tezepelumab. This analysis was made during a time horizon of 50 year and from a third-payer perspective. Results Based on thresholds of U$4828, U$ 5128, and U$19 992 per QALY evaluated in this study, we established economically justifiable drug acquisition prices of U$ 795, U$ 835, and U$ 3384 per dose of Tezepelumab. Tezepelumab not was cost-effective using a WTP of U$4828 and U$ 5128. It only was cost effective at WTP of U$19 992 per QALY Conclusion The economically justifiable cost for tezepelumab in Colombia is between U$795 to U$3384 per dose, depending on the WTP used to decide its implementation. This result should encourage more studies in the region that optimize decision-making processes when incorporating this drug into the health plans of each country.

Effect of single parenteral administration of marbofloxacin on bacterial load and selection of resistant Enterobacteriaceae in the fecal microbiota of healthy pigs

BackgroundAntimicrobial resistance (AMR) is a global concern impacting both humans, animals and their environment. The use of oral antimicrobials in livestock, particularly in pigs, has been identified as a driver in the selection of AMR bacteria. The aim of the present study was to evaluate the effects of a single intramuscular (IM) dose of marbofloxacin (8 mg/kg) on Enterobacteriaceae and E. coli populations, as well as on fluoroquinolone resistance within the fecal microbiota of pigs. Twenty healthy pigs, 60-days old, were divided into two groups: a treated group (n = 13) and a control group (n = 7) and were monitored over a 28-day experimental period. Fecal samples were collected from all animals for the isolation of E. coli and Salmonella strains. The minimum inhibitory concentration (MIC) of marbofloxacin for the isolates recovered on MacConkey agar supplemented with 1 or 4 µg/mL of marbofloxacin and for some generic E. coli isolates (recovered from MacConkey agar not supplemented with marbofloxacin) was determined using the broth microdilution method. Genomic DNA was extracted from the confirmed bacterial strains and sequenced using the Sanger method to identify mutations in the quinolone resistance determining regions (QRDRs) of the gyrA and parC genes.ResultsThe single IM administration of marbofloxacin resulted in a significant decrease in Enterobacteriaceae and E. coli fecal populations from days 1 to 3 post- treatment. No Salmonella isolates were detected in either group, and no marbofloxacin-resistant E. coli isolates were identified. The MIC of the selected generic E. coli strains (n = 100) showed an increase to up to 0.5 µg/mL between days 1 and 3 post-treatment but remained below the clinical breakpoint of marbofloxacin resistance (4 µg/mL). Sequencing of these isolates revealed no mutations in gyrA and parC genes.ConclusionsThe present study showed that this dosing regimen of marbofloxacin significantly decreases the fecal shedding of Enterobacteriaceae and E. coli populations in pigs, while limiting the selection of marbofloxacin-resistant E. coli isolates. These findings warrant validation in sick pigs to support the selective use of this antibiotic solely in cases of clinical disease, thereby minimizing the reliance on conventional (metaphylactic) group treatments in pigs.

Pooled safety evaluation for a new single-shot live-attenuated chikungunya vaccine†.

Chikungunya disease, caused by chikungunya virus (CHIKV), is associated with substantial morbidity, including debilitating CHIKV-related arthralgia. Three clinical trials of a CHIKV vaccine (VLA1553, IXCHIQ®) were conducted in the USA: a Phase 1 dose-finding trial, a pivotal Phase 3 trial and a Phase 3 lot-to-lot consistency trial. Participants were healthy adults (≥18years) and received a single intramuscular dose of VLA1553 (3520 participants) or placebo (1033 participants). Solicited injection site and systemic adverse events (AEs) (10-14days post-vaccination), unsolicited AEs (28 and 180days post-vaccination), AEs of special interest (AESIs) (28days post-vaccination), medically attended AEs (MAAEs), serious AEs (SAEs) (180days post-vaccination) and pregnancies were evaluated. Safety data were pooled, and analyses were descriptive. Overall, 63.7% of participants receiving VLA1553 experienced AEs (44.7% for placebo) that were generally mild. Solicited injection-site AEs, solicited systemic AEs and unsolicited (Day 29) AEs were reported by 15.5, 50.9 and22.7% of participants who received VLA1553 and 11.1, 26.9 and 13.4% who received placebo. Arthralgia was reported by 16.7% of participants who received VLA1553 and 4.8% of participants who received placebo; none required medical attention. MAAEs, AESIs and SAEs were reported by 12.4, 0.3 and 1.5% of participants who received VLA1553 and 11.3, 0.1 and 0.8% of participants who received placebo. Protocol-defined AESIs were mild and short-lived, and two VLA1553-related SAEs resolved without sequelae. There were no clinically important differences in AE incidence based on age or medical history and no VLA1553-related adverse pregnancy outcomes. There were three deaths (two in the VLA1553 group and one in the placebo group); none was vaccine-related. A single dose of VLA1553 presented with an excellent local tolerability profile and overall safety in line with that expected for a live-attenuated vaccine. The safety profile was comparable in participants aged 18-64years and ≥65years.

Investigating the Effect of High-Dose Vitamin D3 Administration on Inflammatory Biomarkers in Patients with Moderate to Severe Traumatic Brain Injury: A Randomized Clinical Trial.

Traumatic brain injury (TBI) is one of the most common neurological disorders worldwide. We aimed to investigate the efficacy of high-dose vitamin D3 on inflammatory biomarkers in patients with moderate to severe TBI. Thirty-five moderate to severe TBI patients were randomly assigned to intervention and control groups. Patients in the intervention group received a single intramuscular (IM) dose of 300,000 IU vitamin D. The primary endpoints were interleukin levels (IL-1β and IL-6), and the secondary endpoints were changes in neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), Glasgow Coma scale (GCS), and Glasgow Outcome Scale-Extended (GOS-E) scores compared between intervention and control arms of the study. The linear Generalized Estimating Equations were used for trend analysis and evaluating the association of independent factors to each outcome. The results revealed a significant decrease in IL-1β levels (-2.71±3.02, in the intervention group: P=0.001 vs. -0.14±3.70, in the control group: P=0.876) and IL-6 (-88.05±148.45, in the intervention group: P=0.0001 vs. -35.54±175.79, in the control groupL P=0.325) 3 days after the intervention. The improvement in the GCS score (P=0.001), reduction in NLR (P=0.001) and PLR (P=0.002), and improvement in the GOS-E score (P=0.039) was found to be greater in the vitamin D3 arm of the study than the control group. Administration of high-dose vitamin D3 in the acute phase of TBI could be effective in lowering the inflammatory markers and improving the level of consciousness and long-term performance outcomes.Trial Registration Number: IRCT20180522039777N2.

N-protein vaccine is effective against COVID-19: Phase 3, randomized, double-blind, placebo-controlled clinical trial

Despite the success of first-generation COVID-19 vaccines targeting the spike (S) protein, emerging SARS-CoV-2 variants have led to immune escape, reducing the efficacy of these vaccines. Additionally, some individuals are unable to mount an effective immune response to S protein-based vaccines. This has created a need for alternative vaccine strategies that are less susceptible to mutations and capable of providing broad and durable protection. This study aimed to evaluate the efficacy and safety of a novel COVID-19 vaccine based on the full-length recombinant nucleocapsid (N) protein of SARS-CoV-2. We conducted a prospective, multicenter, randomized, double-blind, placebo-controlled phase 3 clinical trial (NCT05726084) in Russia. Participants (n=5229) were adults aged 18 years and older, with a BMI of 18.5-30kg/m², and without significant clinical abnormalities. They were randomized in a 2:1 ratio to receive a single intramuscular dose of either the N protein-based vaccine (50µg) or placebo. Randomization was done through block randomization, and masking was ensured by providing visually identical formulations of vaccine and placebo. The primary outcome was the incidence of symptomatic COVID-19 confirmed by PCR more than 15 days after vaccination within a 180-day observation period, analyzed on an intention-to-treat basis. Between May 18, 2023, and August 9, 2023, 5229 participants were randomized, with 3486 receiving the vaccine and 1743 receiving the placebo. Eight cases of PCR-confirmed symptomatic COVID-19 occurred in the vaccine group (0.23%) compared to 27 cases in the placebo group (1.55%), yielding a vaccine efficacy of 85.2% (95% CI: 67.4-93.3; p<0.0001). Adverse events were mostly mild and included local injection site reactions. There were no vaccine-related serious adverse events. The N protein-based COVID-19 vaccine demonstrated significant efficacy and a favorable safety profile, suggesting it could be a valuable addition to the global vaccination effort, particularly in addressing immune escape variants and offering an alternative for those unable to respond to S protein-based vaccines. These results support the continued development and potential deployment of N protein-based vaccines in the ongoing fight against COVID-19.

RAAV expressing a COBRA-designed influenza hemagglutinin generates a protective and durable adaptive immune response with a single dose.

Developing an improved seasonal influenza vaccine remains an ambitious goal of researchers and clinicians alike. With influenza routinely causing severe epidemics with the potential to rise to pandemic levels, it is critical to create an effective, broadly protective, and durable vaccine to improve public health worldwide. As a potential solution, we created a rAAV viral vector expressing a COBRA-optimized influenza hemagglutinin antigen with modestly enriched CpG motifs to evoke a robust and long-lasting immune response after a single intramuscular dose without needing boosts or adjuvants. Importantly, the rAAV vaccine boosted antibody breadth to future strains in ferrets with pre-existing influenza immunity. Together, our data support further investigation into the utility of viral vectors as a potential avenue to improve our seasonal influenza vaccines.

Synergistic Effect of Maternal Micronutrient Supplementation on ORFV DNA Vaccine Immune Response in a Pregnant Model.

Contagious ecthyma is a contagious zoonotic disease caused by the Orf virus that can infect farm animals and humans, but no vaccine is available for pregnant mothers. Excessive oxidative stress during pregnancy can suppress the vaccine immune response in pregnant mothers; hence, maternal micronutrient supplementation could effectively improve the immune response, health, and oxidative status during pregnancy. In this study, we employed an 8-week-old pregnant rat model to receive a single intramuscular dose of 200µg of ORF DNA vaccine with or without vitamin E and selenium supplementation to evaluate their effect on immune responses (specific IgG and IgG isotypes), oxidative stress, liver enzymes, and blood glucose levels in maternal-neonatal serum and milk secretions. Additionally, antioxidant-related gene expressions were analyzed in the maternal placenta and pups' liver. The results showed that supplementation of vitamin E and selenium with ORF DNA vaccination increased the production of specific antibody and IgG isotypes (IgG1 and IgG2a) and reduced the oxidative stress in neonatal-maternal serum and milk compared to both the control group and those vaccinated without supplementation (p < 0.05). Notably, the ORF DNA vaccine did not cause oxidative stress and hepatic damage. However, combined supplementation of vitamin E and selenium with DNA vaccination significantly decreased serum malondialdehyde (MDA) levels and improved the antioxidant-related enzyme activities of glutathione peroxidase (GPX), superoxide dismutase 1 (SOD1), and selenoprotein P (SELP) in the maternal placenta and liver of pups (p < 0.05). In conclusion, maternal supplementation of vitamin E and selenium enhanced the immune responses of the ORF DNA vaccine by mitigating oxidative stress in pregnant rats and could thus be a promising strategy for better health outcomes for both mothers and neonates.

Comprehensive Summary of Safety Data on Nirsevimab in Infants and Children from All Pivotal Randomized Clinical Trials.

Nirsevimab is approved in the US for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants during their first RSV season and in children aged ≤24 months who remain vulnerable to severe RSV disease through their second RSV season. We summarize a pre-specified analysis of nirsevimab safety data from three randomized controlled trials: Phase 2b (NCT02878330; healthy infants born ≥29 to <35 weeks' gestational age [wGA]); Phase 3 MELODY (NCT03979313; healthy infants born ≥35 wGA); and Phase 2/3 MEDLEY (NCT03959488; infants with congenital heart disease [CHD] and/or chronic lung disease of prematurity [CLD] or born ≤35 wGA). Participants (randomized 2:1) received a single intramuscular dose of nirsevimab or comparator (placebo, Phase 2b/MELODY; 5× once-monthly palivizumab, MEDLEY) before their first RSV season (recipients < 5 kg, nirsevimab 50 mg; ≥5 kg, nirsevimab 100 mg). In MEDLEY, children with CHD/CLD continued to a second RSV season: first-season nirsevimab recipients received nirsevimab 200 mg; first-season palivizumab recipients were re-randomized 1:1 to receive nirsevimab 200 mg or 5× once-monthly palivizumab. The incidence, severity, and nature of AEs were similar across treatments (nirsevimab, n = 3184; placebo, n = 1284; palivizumab, n = 304). Most AEs were mild to moderate in severity, with ≥98% unrelated to treatment. AEs of special interest occurred infrequently (<1%): no anaphylaxis or thrombocytopenia were treatment-related, and no immune complex disease was reported. Deaths (incidence < 1.0%) were all unrelated to treatment. A single dose per season of nirsevimab for the prevention of RSV disease had a favorable safety profile, irrespective of wGA or comorbidities.

Population pharmacokinetics of butorphanol following intramuscular administration to exercised thoroughbred horses.

Butorphanol is commonly administered, both by the intravenous and intramuscular routes, to racehorses to facilitate handling for diagnostic procedures. As the administration of butorphanol for therapeutic purposes is considered appropriate, in order to avoid inadvertent positive drug tests, a thorough understanding of the pharmacokinetics of this drug is necessary. In the current study, 12, exercised Thoroughbred horses were administered a single intramuscular dose of 0.1 mg/kg butorphanol, and serum and urine samples were collected at various times post drug administration for determination of butorphanol concentrations using a highly sensitive liquid chromatography tandem mass spectrometry method. Serum data were modeled using a nonlinear mixed effect population PK model. The maximum concentration (C max) and time to maximum concentration (T max) were 139.9 ± 72.8 ng/mL and 0.43 ± 0.44 h (mean ± SD), respectively. Although likely not clinically relevant, but important for drug testing purposes, a prolonged terminal phase was observed, yielding a terminal half-life of 7.67 ± 1.86 h. Using the blood screening limits proposed by the Horseracing Integrity and Welfare Unit, the detection time for intramuscular administration of butorphanol was estimated to be 96 h.

Comparing IM Lorazepam and IM Clothiapine for Agitated Psychosis in Hospitalized Patients

IntroductionWhen patients in a closed hospital ward experience acute psychosis and become highly agitated or pose a risk to themselves and others, it’s often crucial to provide immediate sedative treatment. However, there is currently no consensus on whether the preferred medication for these situations should be antipsychotic drugs or benzodiazepines.ObjectivesThis study aimed to compare how well a single intramuscular dose of 2-4 mg Lorazepam performs against 40 mg Clothiapine in terms of effectiveness and side effects. These treatments were administered as immediate emergency measures to patients experiencing psychosis with severe agitation or behaviors that posed a risk to themselves or their surroundings.MethodsWe conducted a retrospective clinical study involving 100 patients experiencing aggressive psychosis. These patients were divided into two groups. The first group comprised 50 patients who received a single intramuscular (IM) dose of up to 40 mg Clothiapine. The second group consisted of 50 patients who received IM treatment with 2-4 mg Lorazepam. We assessed the patients’ outcomes around 8 hours after treatment or upon receiving any additional treatment.ResultsThere were no significant statistical differences in the demographic and clinical characteristics (e.g., age, gender, number of hospitalizations, duration of illnesses, psychiatric diagnosis, comorbidity) of the patients between the two groups (p &gt; 0.05).Before treatment, there were no statistical differences in the severity of clinical symptoms (CGI-S) between the two groups [CGI-S (Mean ± SD): 5.32 ± 1.09 vs. 5.38 ± 1.4, p = 0.8].However, in the Clothiapine group, a statistically significant clinical improvement (CGI-I) was observed after treatment [CGI-I (Mean ± SD): 2.42 ± 0.9 vs. 1.96 ± 1.16, p = 0.029 *].There were no significant differences in the need for physical restraint or additional medication following the initial treatment between the two groups (p &gt; 0.05).Furthermore, there were no statistically significant differences in the major side effects of the drugs, the necessity for referral to the general emergency room, or incidents of falls (p &gt; 0.05).ConclusionsWhen dealing with a psychotic state marked by severe agitation or threats to oneself and others, the use of IM Clothiapine as a treatment option may offer certain advantages over IM Lorazepam. Importantly, these advantages come without significant exposure to side effects or potential risks associated with Clothiapine.Disclosure of InterestNone Declared

The safety and immunogenicity of a bivalent conjugate vaccine against Salmonella enterica Typhi and Paratyphi A in healthy Indian adults: a phase 1, randomised, active-controlled, double-blind trial

Enteric fever caused by Salmonella enterica Typhi and Salmonella Paratyphi A is an important public health problem, especially in low-income and middle-income countries with limited access to safe water and sanitation. We present results from, to our knowledge, the first ever human study of a bivalent paratyphoid A-typhoid conjugate vaccine (Sii-PTCV). In this double-blind phase 1 study, 60 healthy Indian adults were randomly assigned (1:1) to receive a single intramuscular dose of either Sii-PTCV or typhoid conjugate vaccine (Typbar-TCV). Safety was assessed by observing solicited adverse events for 1 week, unsolicited events for 1 month, and serious adverse events (SAEs) over 6 months. Immunogenicity at 1 month and 6 months was assessed by measuring anti-capsular polysaccharide antigen Vi (anti-Vi) IgG and IgA against Salmonella Typhi and anti-lipopolysaccharide (LPS) IgG against Salmonella Paratyphi A by ELISA, and functional antibodies using serum bactericidal assay (SBA) against Salmonella Paratyphi A. This study is registered with Clinical Trial Registry-India (CTRI/2022/06/043608) and is completed. 60 participants were enrolled. Of these 60 participants, 57 (95%) participants were male and three (5%) participants were female. Solicited adverse events were observed in 27 (90%) of 30 participants who received Sii-PTCV and 26 (87%) of 30 participants who received Typbar-TCV. The most common local solicited event was pain in 27 (90%) participants who received Sii-PTCV and in 23 (77%) participants who received Typbar-TCV. The most common solicited systemic event was myalgia in five (17%) participants who received Sii-PTCV, whereas four (13%) participants who received Typbar-TCV had myalgia and four (13%) had headache. No vaccine-related unsolicited adverse events or SAEs were reported. The seroconversion rates on day 29 were 96·7% (95% CI 82·8-99·9) with Sii-PTCV and 100·0% (88·4-100·0) with Typbar-TCV for anti-Vi IgG; 93·3% (77·9-99·2) with Sii-PTCV and 100·0% (88·4-100·0) with Typbar-TCV for anti-Vi IgA; 100·0% (88·4-100·0) with Sii-PTCV and 3·3% (0·1-17·2) with Typbar-TCV for anti-LPS (paratyphoid); and 93·3% (77·9-99·2) with Sii-PTCV and 0% (0·0-11·6) with Typbar-TCV for SBA titres (paratyphoid). Paratyphoid anti-LPS immune responses were sustained at day 181. Sii-PTCV was safe and immunogenic for both typhoid and paratyphoid antigens indicating its potential for providing comprehensive protection against enteric fever. Serum Institute of India.

Exploratory analysis of the economically justifiable price of nirsevimab for healthy late-preterm and term infants in Colombia.

Respiratory syncytial virus infection is the leading cause of lower respiratory infection globally. Recently, nirsevimab has been approved to prevent respiratory syncytial virus (RSV) infection. This study explores the economically justifiable price of nirsevimab for preventing RSV infection in Colombia's children under 1 year of age. A static model was developed using the decision tree microsimulation to estimate the quality-adjusted costs and life years of two interventions: a single intramuscular dose of nirsevimab versus not applying nirsevimab. This analysis was made during a time horizon of 1 year and from a societal perspective. The annual savings in Colombia associated with this cost per dose ranged from U$ 2.5 to 4.1 million. Based on thresholds of U$ 4828, U$ 5128, and U$ 19 992 per QALY evaluated in this study, we established economically justifiable drug acquisition prices of U$ 21.88, U$ 25.04, and U$ 44.02 per dose of nirsevimab. the economically justifiable cost for nirsevimab in Colombia is between U$ 21 to U$ 44 per dose, depending on the willingness to pay used to decide its implementation. This result should encourage more studies in the region that optimize decision-making processes when incorporating this drug into the health plans of each country.

PHARMACOKINETICS OF SINGLE INTRAMUSCULAR ADMINISTRATION OF CEFTIOFUR CRYSTALLINE FREE ACID IN AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS).

A pharmacokinetic study of ceftiofur crystalline free acid sterile oil suspension (CCFA) was performed in six apparently healthy juvenile American alligators (Alligator mississippiensis). A single intramuscular dose of 30 mg/kg was administered in the triceps muscle. Blood samples were collected prior to treatment and at 4, 12, 24, 48, 72, 120, 144, 192, 288, and 366 h post administration. Plasma samples were analyzed for ceftiofur equivalent concentrations using liquid chromatography-mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental analysis. Mean peak plasma concentration was 23.2 µg/ml (range, 16.0-27.9), median time to maximum concentration was 72 h (range, 72-120), mean area under the curve from 0 to 366 h postdose was 4.24 h · mg/ml (range, 3.54-4.97), and mean terminal half-life was 143 h (range, 90.8-220). Plasma concentrations were maintained above the minimum inhibitory concentration for this study of 2.0 µg/ml, which was established from similar CCFA pharmacokinetic studies in other reptilian species, through the end of the data collection of 366 h. Because of prolonged plasma concentrations, a dosing interval could not be established in this study. Future studies should include extended collection time points and multidose studies to determine dosing regimens.

Frequency of cardiotoxicity following intramuscular administration of epinephrine in emergency department patients with anaphylaxis.

Epinephrine can be a life-saving treatment for patients with anaphylaxis. Potential cardiovascular side effects of epinephrine may contribute to clinician hesitancy to use it. However, the frequency of cardiotoxicity resulting from epinephrine treatment for anaphylaxis is not well described. We sought to describe the frequency of cardiotoxicity following intramuscular (IM) administration of epinephrine in adult emergency department (ED) patients with anaphylaxis. We conducted a retrospective observational study at a single, quaternary care academic ED in Tennessee. We identified consecutive ED visits with the diagnosis of anaphylaxis from 2017 to 2021 who received at least one intramuscular (IM) dose of epinephrine in the ED. Analysis was primarily descriptive. The primary outcome was cardiotoxicity, the occurrence of any of the following after epinephrine administration: ischemic electrocardiogram changes, systolic blood pressure>200mmHg, or cardiac arrest ≤4h; elevated troponin ≤12h; or percutaneous coronary intervention or depressed ejection fraction ≤72h. Among 338 included patients, 16 (4.7%; 95%CI: 2.8-7.6%) experienced cardiotoxicity. Cardiotoxic events included eight (2.4%) ischemic electrocardiogram changes, six (1.8%) episodes of elevated troponin, five (1.5%) atrial arrhythmias, one (0.3%) ventricular arrythmia, and one (0.3%) depressed ejection fraction. Patients with cardiotoxicity were significantly older, had more comorbidities, and were more likely to have received multiple doses of epinephrine or an epinephrine infusion compared with a single IM dose of epinephrine. Among 338 consecutive adult ED patients who received IM epinephrine for anaphylaxis during a recent 4-year period, cardiotoxic side effects were observed in approximately 5% of patients.

MVA-based vaccine candidates expressing SARS-CoV-2 prefusion-stabilized spike proteins of the Wuhan, Beta or Omicron BA.1 variants protect transgenic K18-hACE2 mice against Omicron infection and elicit robust and broad specific humoral and cellular immune responses.

Despite the decrease in mortality and morbidity due to SARS-CoV-2 infection, the incidence of infections due to Omicron subvariants of SARS-CoV-2 remains high. The mutations acquired by these subvariants, mainly concentrated in the receptor-binding domain (RBD), have caused a shift in infectivity and transmissibility, leading to a loss of effectiveness of the first authorized COVID-19 vaccines, among other reasons, by neutralizing antibody evasion. Hence, the generation of new vaccine candidates adapted to Omicron subvariants is of special interest in an effort to overcome this immune evasion. Here, an optimized COVID-19 vaccine candidate, termed MVA-S(3P_BA.1), was developed using a modified vaccinia virus Ankara (MVA) vector expressing a full-length prefusion-stabilized SARS-CoV-2 spike (S) protein from the Omicron BA.1 variant. The immunogenicity and efficacy induced by MVA-S(3P_BA.1) were evaluated in mice in a head-to-head comparison with the previously generated vaccine candidates MVA-S(3P) and MVA-S(3Pbeta), which express prefusion-stabilized S proteins from Wuhan strain and Beta variant, respectively, and with a bivalent vaccine candidate composed of a combination of MVA-S(3P) and MVA-S(3P_BA.1). The results showed that all four vaccine candidates elicited, after a single intramuscular dose, protection of transgenic K18-hACE2 mice challenged with SARS-CoV-2 Omicron BA.1, reducing viral loads, histopathological lesions, and levels of proinflammatory cytokines in the lungs. They also elicited anti-S IgG and neutralizing antibodies against various Omicron subvariants, with MVA-S(3P_BA.1) and the bivalent vaccine candidate inducing higher titers. Additionally, an intranasal immunization in C57BL/6 mice with all four vaccine candidates induced systemic and mucosal S-specific CD4+ and CD8+ T-cell and humoral immune responses, and the bivalent vaccine candidate induced broader immune responses, eliciting antibodies against the ancestral Wuhan strain and different Omicron subvariants. These results highlight the use of MVA as a potent and adaptable vaccine vector against new emerging SARS-CoV-2 variants, as well as the promising feature of combining multivalent MVA vaccine candidates.

2888. Safety and Immunogenicity of an Adjuvanted Chikungunya Virus (CHIKV) Virus-like Particle (VLP) Based Vaccine in Two Pivotal Phase 3 Trials, ≥12 Years of Age

Abstract Background CHIKV remains a significant public health concern globally. We report the results of two phase 3 trials evaluating an aluminum hydroxide adjuvanted CHIKV VLP vaccine. Methods Two multicenter, randomized, double-blind, placebo-controlled, parallel-group trials were conducted: an adult/adolescent trial (NCT05072080) in ages 12-64 years and an older adult trial in ages ≥ 65 years (NCT05349617). Participants received CHIKV VLP vaccine or placebo as a single intramuscular dose. Immunogenicity objectives assessed anti-CHIKV NT80 serum neutralizing antibody (SNA) titers at selected timepoints. Seroresponse rate (SRR) was the percentage of participants who achieved NT80 SNA titer ≥ 100 (FDA/EMA agreed threshold). Safety outcomes were evaluated through monitoring adverse events (AEs) through Day 183. Study overview. Results Adult/adolescent trial: 3254 participants (2790 CHIKV VLP vaccine, 464 placebo) were enrolled. Primary endpoints were met with a Day 22 SRR of 98% (2503/2559) for vaccine and 1% for placebo (5/424; p&amp;lt; 0.0001), as well as lot consistency, and superiority to placebo in geometric mean titer (GMT). A rapid antibody response was observed in the CHIKV VLP vaccine group with Day 8 SRR=47% (1169/2510) and Day 15 SRR=97% (2355/2434); responses were durable through Day 183 with SRR=86% (1967/2301). Older adult trial: 413 participants (206 CHIKV VLP vaccine, 207 placebo) were enrolled. Primary endpoints were met with a Day 22 SRR of 87% (167/191) for vaccine and 1% for placebo (2/183; p&amp;lt; 0.0001), as well as by GMT. At Day 15 a rapid antibody response was observed in the CHIKV VLP vaccine group with SRR=82% (150/182). CHIKV VLP vaccine demonstrated a favorable safety profile, and most AEs were mild to moderate in severity. The most common AEs were myalgia, fatigue, and headache. Conclusion CHIKV VLP vaccine is the only VLP-based vaccine in clinical development for active immunization against CHIKV disease. Results demonstrate that CHIKV VLP vaccine induces a rapid and robust immune response in most people by Day 15 and through Day 183. These findings support the potential of this VLP-based vaccine to help protect individuals 12 years and older from CHIKV. Disclosures Jason S. Richardson, PhD, Bavarian Nordic Canada Inc: Stocks/Bonds Debbie Anderson, MS, Bavarian Nordic: Employee|Emergent BioSolutions: Stocks/Bonds Sufia Muhammad, MD, Bavarian Nordic: Employee|Emergent BioSolutions: Stocks/Bonds Lauren Tindale, PhD, Bavarian Nordic: Employee Tobi Loreth, n/a, Emergent BioSolutions: Stocks/Bonds Sarah Royalty Tredo, MBA, Emergent Biosolutions: Employee|Emergent Biosolutions: Stocks/Bonds Victoria Jenkins, PhD, Bavarian Nordic: Employee Patrick Ajiboye, MD, Bavarian Nordic: Employee|Emergent BioSolutions: Stocks/Bonds Lisa Bedell, Director Biostatistic, Bavarian-Nordic: Advisor/Consultant|Emergent BioSolutions: Employee|Emergent BioSolutions: Stocks/Bonds

Comparison of pharmacokinetics and safety between CE-fosphenytoin sodium, fosphenytoin sodium, and phenytoin sodium after intravenous and intramuscular administration in healthy volunteers.

Background: Captisol®-enabled-fosphenytoin sodium (CE-fosphenytoin sodium) injection is a modified formulation of fosphenytoin sodium. Objective: We aim to compare the intravenous and intramuscular bioavailability and safety between CE-fosphenytoin sodium, fosphenytoin sodium (Cerebyx®), and phenytoin sodium (intravenous injection only). Methods: In pivotal study 1, 54 subjects were divided into three sequence groups that receive intravenous injection of 250mg of phenytoin sodium equivalent (PE), CE-fosphenytoin sodium (T), or fosphenytoin sodium (R1) and 250mg of phenytoin sodium (R2) in period 1. After a 14-day washout period, 36 subjects were randomized to two treatment sequence groups (T-R1 or R1-T, n = 18 per group) in period 2, in which the subjects who received R2 in period 1 were removed, those who received T in period 1 used R1 (T-R1), while those who previously received R1 used T (R1-T). In pivotal study 2, a single intramuscular dose of T (400mg PE) or R1 (400mg PE) was administered according to the individual sequential treatment assignment in each period. There was a washout (14days) period before receiving the next period study drug. Results: T and R1 have similar pharmacokinetic characteristics regarding total and free phenytoin, showing bioequivalence of both drugs in the intravenous and intramuscular administration. The geometric mean ratio was close to 1 (0.98-1.06). The AUC of total and free phenytoin in subjects who intravenously received T and R1 was very similar to those who received R2, although their Cmax was lower than that of the subjects who received R2. Overall, treatment with T and R1 was safe and well-tolerated, without serious adverse events (SAEs) or grade III adverse events (AEs). With intravenous (i.v.) or intramuscular (i.m.) treatment, the incidence of drug-related AEs using T was similar to that using R1. Treatment with T and R1 had clearly superior tolerability than that with R2. Conclusion: CE-fosphenytoin sodium is a promising substitute for fosphenytoin sodium. Clinical Trial Registration: http://www.chinadrugtrials.org.cn/, CTR20202154 (11 November 2020).