Antivirals, Antimicrobial Resistance & Vaccines
A comprehensive analysis of the infectious disease clinical trial landscape — from microbiology infrastructure and rapid diagnostic integration to antimicrobial stewardship alignment and pipeline dynamics across antivirals, novel antibiotics, and next-generation vaccines.
The Infectious Disease Trial Landscape in 2026
Infectious disease clinical development occupies a unique position in the therapeutic landscape, driven by the dual imperatives of addressing the growing antimicrobial resistance (AMR) crisis and leveraging the transformative vaccine platform technologies that emerged from the COVID-19 pandemic response. Within the Clinitiative network, infectious disease encompasses 12 active studies spanning antivirals for HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), respiratory syncytial virus (RSV), and influenza; antibiotics targeting AMR organisms; next-generation vaccines; and antifungal agents for invasive fungal infections. While numerically smaller than some therapeutic areas, the infectious disease portfolio carries outsized strategic importance due to the global public health implications of AMR, the expanding vaccine pipeline, and the ongoing investment in pandemic preparedness infrastructure.
Antimicrobial resistance is a growing global priority that the World Health Organization has designated as one of the top ten threats to global health. AMR-related studies account for 4 of the 12 active protocols in our network, targeting multidrug-resistant gram-negative pathogens, methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Enterobacterales (CRE). The antiviral portfolio includes 4 studies focused on HIV long-acting prevention and cure-directed research, HBV functional cure approaches, and broad-spectrum antiviral development. The vaccine pipeline contributes 3 studies leveraging mRNA and protein-based platforms for RSV, influenza, and cytomegalovirus (CMV) prevention. One additional study targets invasive aspergillosis in immunocompromised populations.
The infectious disease landscape in 2026 is characterized by several defining trends: the expansion of RSV prevention programs across age groups and risk populations, continued investment in HIV cure and functional cure research that pushes the boundaries of what is achievable in chronic viral infection, the application of mRNA vaccine technology to an expanding array of pathogens beyond COVID-19, and the critical but commercially challenging effort to develop novel antibiotics against resistant organisms. The pandemic preparedness infrastructure built during the COVID-19 era — including rapid-enrollment clinical trial networks, adaptive platform trial designs, and emergency use authorization pathways — continues to serve as a foundation for infectious disease clinical development.
Key Performance Metrics
Network-wide benchmarks from our infectious disease portfolio provide critical reference points for study planning and site performance evaluation across antiviral, antibiotic, and vaccine indications.
Enrollment rates in infectious disease vary widely by indication and study design. Vaccine studies consistently achieve the highest enrollment at 3.5 patients per site per month, benefiting from large eligible populations in healthy volunteer and at-risk cohorts with streamlined screening criteria. HIV treatment and prevention studies average 1.8 patients per site per month, reflecting the more specialized population and the need for resistance testing and viral load confirmation during screening. AMR antibiotic studies, which require identification of patients with confirmed resistant infections within narrow treatment windows, average 1.4 patients per site per month and demand hospital-based sites with active ICU and emergency department patient flow.
The infectious disease portfolio maintains one of the lowest overall screen failure rates in our network, reflecting the well-defined diagnostic criteria for most infectious disease indications. Vaccine studies contribute the lowest screen failure rates at 8-12%, as healthy volunteer eligibility criteria are broadly inclusive. However, HIV studies demonstrate significantly higher screen failure rates at 28%, driven by antiretroviral resistance testing requirements, viral load thresholds, and CD4 count criteria that exclude a meaningful proportion of screened patients. AMR antibiotic studies have moderate screen failure rates at 20-25%, primarily related to pathogen confirmation and susceptibility testing timelines.
Infectious disease site startup timelines reflect the moderate infrastructure requirements of the therapeutic area, balanced against heightened IRB sensitivity for certain pathogen-related studies and vulnerable population protections. Vaccine studies achieve the fastest startup at 10 weeks, supported by well-established regulatory pathways and standardized cold chain qualification processes. HIV studies average 13 weeks due to additional regulatory requirements for vulnerable population protections and community advisory board engagement. AMR antibiotic studies require the longest startup at 14-15 weeks, as hospital-based sites must coordinate with infection control, antimicrobial stewardship teams, and microbiology laboratories to establish study-specific identification and enrollment workflows.
Patient retention across infectious disease studies benefits from high patient motivation, particularly in HIV populations where participants are often deeply engaged in their care and have established relationships with clinical research sites. HIV studies achieve the highest retention at 88-90%, reflecting the strong patient-site relationships cultivated over decades of HIV clinical research. Vaccine studies maintain retention at 82-85%, with most attrition occurring during long-term follow-up phases after the acute immunogenicity assessment period. AMR antibiotic studies, which are typically shorter in duration, achieve 80% completion rates, with treatment failure and clinical deterioration driving the majority of discontinuations.
Network Capabilities
Executing infectious disease trials requires a distinctive set of capabilities that span microbiology, vaccine logistics, biocontainment, and antimicrobial pharmacology. Our network has been developed to provide comprehensive infectious disease research support, from pathogen identification and characterization to immunogenicity assessment and antimicrobial stewardship integration.
Microbiology & Virology Laboratory
Infectious disease clinical trials depend on rapid and accurate pathogen identification, quantification, and characterization. Our network sites maintain established relationships with CLIA-certified microbiology and virology laboratories capable of bacterial culture and antimicrobial susceptibility testing, viral load quantification by PCR for HIV, HBV, HCV, and respiratory pathogens, genotypic and phenotypic resistance testing, and serologic assays for baseline immune status assessment. Sites with on-site microbiology capabilities achieve pathogen identification turnaround times of 24-48 hours for culture-based methods and 4-6 hours for rapid molecular diagnostics, enabling timely enrollment decisions within the narrow treatment windows that characterize many infectious disease protocols.
For AMR-focused studies, our sites maintain real-time surveillance relationships with hospital microbiology laboratories that enable automated alerts when qualifying resistant organisms are identified from clinical specimens. This integration allows research coordinators to assess potential study candidates within hours of pathogen identification, a critical capability when enrollment windows may be as narrow as 24-72 hours from clinical presentation.
Vaccine Trial Infrastructure
Vaccine clinical trials require specialized infrastructure that spans cold chain management, immunogenicity sample processing, and systematic reactogenicity monitoring. Our network sites maintain validated cold chain systems with continuous temperature monitoring, including standard refrigeration (2-8 degrees C), freezer storage (-20 degrees C), and ultra-cold capabilities (-80 degrees C) for mRNA vaccine products. Cold chain integrity is documented through calibrated data loggers with automated alarm systems that notify designated personnel of temperature excursions in real time, ensuring investigational product integrity from receipt through administration.
Immunogenicity sample processing capabilities include serum separation within protocol-specified timeframes, peripheral blood mononuclear cell (PBMC) isolation for cellular immunity assessment, and standardized aliquoting and storage protocols that ensure specimen quality for downstream serologic and cellular immunogenicity analyses. Reactogenicity monitoring is conducted through electronic diary systems that capture solicited local and systemic adverse events in the post-vaccination observation period, with established protocols for managing anaphylaxis and other acute hypersensitivity reactions during the required 15-30 minute post-vaccination observation window.
BSL-2 Sample Handling & Biocontainment
Infectious disease research involves handling specimens that contain viable pathogens, requiring biosafety level 2 (BSL-2) capabilities for specimen processing, storage, and shipment. Our network sites maintain BSL-2 laboratory spaces with certified biological safety cabinets, pathogen-specific standard operating procedures for specimen handling, and trained personnel who follow institutional biosafety committee (IBC) approved protocols. Shipping compliance is ensured through IATA-certified packaging and documentation for category B biological substances, with established courier relationships that maintain chain-of-custody documentation from collection through delivery to central laboratories.
For studies involving highly pathogenic organisms or novel pathogens, our sites implement enhanced biocontainment protocols including dedicated specimen processing areas, point-of-collection inactivation methods when permitted by the protocol, and waste management procedures that comply with federal and state regulations for biohazardous material disposal. These capabilities ensure both personnel safety and specimen integrity across the infectious disease research portfolio.
Antimicrobial Stewardship Integration
Antibiotic clinical trials must operate within the context of institutional antimicrobial stewardship programs (ASPs) that govern antibiotic prescribing practices. Our network sites maintain collaborative relationships with ASP teams, including infectious disease pharmacists who provide pharmacokinetic and pharmacodynamic (PK/PD) sampling support, dosing optimization guidance, and therapeutic drug monitoring capabilities. This integration ensures that study protocols align with institutional stewardship principles and that research antibiotic use is appropriately documented and distinguished from standard-of-care prescribing.
PK/PD sampling is a critical component of many early-phase antibiotic programs, requiring precise specimen collection at protocol-specified timepoints relative to drug administration. Our sites maintain dedicated PK sampling infrastructure including timed blood draw protocols, immediate specimen processing on ice, and ultra-cold storage for PK samples that ensures analyte stability. Sites with established PK/PD sampling experience achieve protocol-compliant collection rates exceeding 95%, minimizing missing data that can compromise pharmacokinetic modeling and dose selection decisions.
Enrollment Dynamics
Infectious disease enrollment dynamics are uniquely influenced by pathogen epidemiology, seasonal transmission patterns, healthcare system access points, and the diverse patient populations affected by different infectious agents. Understanding these dynamics is essential for realistic enrollment planning and site selection across the infectious disease portfolio.
HIV recruitment benefits from decades of established infrastructure, including specialized HIV clinics, community-based organizations, and patient advocacy networks that maintain deep engagement with affected populations. Our network leverages these established channels to recruit for both treatment and prevention studies, with HIV-experienced sites maintaining active patient registries and community advisory boards that facilitate rapid enrollment activation. The transition from daily oral antiretroviral therapy to long-acting injectable formulations has generated strong patient interest in clinical trial participation, as many patients are motivated by the convenience of less frequent dosing.
AMR antibiotic studies present fundamentally different enrollment dynamics, as they require hospital-based sites with active patient flow from intensive care units, emergency departments, and inpatient medical wards where resistant infections are diagnosed and treated. Enrollment is driven by real-time microbiology alerts rather than outpatient screening, and the enrollment window is typically constrained to 24-72 hours from clinical presentation. Our network addresses this through 24/7 on-call research coordinator coverage at hospital-based sites, automated microbiology laboratory alert systems, and streamlined enrollment workflows that enable rapid consent and randomization for acutely ill patients.
Vaccine studies benefit from large primary care and community health networks that provide access to the broad populations targeted by preventive vaccination programs. RSV vaccine studies recruit from older adult populations and pregnant women during defined seasonal windows when RSV transmission is expected, requiring careful coordination of enrollment timing with regional respiratory virus epidemiology. Influenza vaccine studies similarly depend on seasonal recruitment windows. Our network maintains pandemic readiness infrastructure that can be rapidly activated for emerging pathogen vaccine studies, including pre-negotiated site agreements, rapid IRB review pathways, and community engagement protocols that support accelerated enrollment timelines when public health urgency demands expedited clinical evaluation.
Key Challenges in Infectious Disease Trial Execution
The pathogen-dependent nature of infectious disease research and the diverse patient populations involved present operational challenges that require specialized strategies and infrastructure.
Pathogen-Specific Recruitment Timing
Many infectious disease studies are inherently constrained by pathogen epidemiology, creating enrollment windows that may be seasonal, outbreak-dependent, or geographically variable. RSV and influenza vaccine studies must align enrollment with anticipated respiratory virus seasons, typically October through March in the Northern Hemisphere, requiring sites to achieve full enrollment readiness before the season begins and to maximize enrollment velocity during the active transmission period. AMR antibiotic studies depend on the prevalence of specific resistant organisms at participating sites, which can fluctuate with institutional infection control practices, antibiotic prescribing patterns, and regional epidemiologic trends. Our network addresses timing-dependent enrollment through predictive epidemiologic modeling, pre-season site activation protocols, multi-hemisphere enrollment strategies that extend available recruitment windows, and real-time enrollment dashboards that enable rapid reallocation of targets between sites based on observed pathogen prevalence.
Antimicrobial Resistance Phenotyping
AMR antibiotic studies require rapid identification and characterization of resistant organisms to confirm enrollment eligibility within clinically relevant treatment windows. The challenge is that conventional culture and susceptibility testing can require 48-72 hours, while many study protocols require enrollment within 24-48 hours of clinical presentation. Our network addresses this through integration of rapid molecular resistance diagnostics at participating hospital sites, including PCR-based panels that identify resistance genes (mecA, vanA/B, carbapenemase genes) within 1-4 hours from positive blood cultures or clinical specimens. Sites with rapid diagnostic capabilities achieve 2-3x higher enrollment conversion rates compared to sites relying solely on conventional microbiology, as eligible patients can be identified and consented before the enrollment window closes.
Stigma & Vulnerable Population Protections
Infectious disease research frequently involves patient populations that face social stigma related to their diagnosis or risk factors, including people living with HIV, individuals with viral hepatitis who may have a history of injection drug use, and communities disproportionately affected by sexually transmitted infections. These populations require enhanced informed consent processes, culturally sensitive recruitment approaches, and rigorous privacy protections that go beyond standard clinical trial safeguards. Our network sites implement community advisory board engagement for HIV and hepatitis studies, multilingual consent processes, confidentiality protocols that protect participant identity throughout the research process, and research staff training in trauma-informed care and stigma reduction. Sites with established community trust achieve 40% higher enrollment rates and 15% better retention compared to sites without community engagement infrastructure.
Regulatory Complexity for Vaccines
Vaccine clinical trials operate under a regulatory framework that includes unique requirements not present in most therapeutic development programs. Data Safety Monitoring Board (DSMB) oversight with pre-specified stopping rules is standard for vaccine studies, requiring robust real-time safety data collection and reporting infrastructure. Pediatric vaccine studies involve additional regulatory protections for minors, including risk-benefit assessments that must demonstrate that the study presents only a minor increase over minimal risk when no direct therapeutic benefit is expected. Emergency use authorization (EUA) pathways, established during the COVID-19 pandemic, introduce additional regulatory complexity for vaccines targeting emerging pathogens, including expedited safety database requirements and real-world evidence collection obligations. Our network maintains regulatory affairs expertise specific to vaccine development, including DSMB coordination experience, pediatric assent and parental consent processes, and EUA submission support capabilities.
Pipeline Analysis
The infectious disease development pipeline reflects the convergence of longstanding therapeutic goals — such as HIV cure and AMR solutions — with transformative platform technologies that are enabling entirely new approaches to prevention and treatment. Several key therapeutic trends are driving shifts in trial design, site requirements, and enrollment strategy across the infectious disease landscape.
HIV Cure & Long-Acting Prevention
HIV cure-directed research represents the most ambitious goal in infectious disease, with multiple strategies advancing through early and mid-phase clinical development. Broadly neutralizing antibodies (bNAbs) targeting conserved HIV envelope epitopes are being evaluated both as therapeutic agents for viral reservoir reduction and as long-acting prevention tools. Latency-reversing agents aim to flush HIV from latent reservoirs, making hidden virus susceptible to immune-mediated clearance or direct antiviral killing. Long-acting injectable pre-exposure prophylaxis (PrEP) with cabotegravir has established the paradigm for less-frequent dosing, and next-generation long-acting agents including lenacapavir are extending dosing intervals to every six months, transforming HIV prevention accessibility. These programs require sites with deep HIV expertise, antiretroviral treatment interruption management protocols, intensive viral load monitoring capabilities, and community engagement infrastructure that supports recruitment of diverse populations for both cure and prevention studies.
Next-Generation Antivirals
The antiviral pipeline extends beyond HIV to address significant unmet needs in hepatitis B, respiratory viruses, and pandemic preparedness. HBV functional cure — defined as sustained loss of hepatitis B surface antigen (HBsAg) after treatment discontinuation — is being pursued through combination approaches that pair direct-acting antivirals with immune modulators, therapeutic vaccines, RNA interference agents, and capsid assembly modulators. Broad- spectrum antivirals targeting conserved viral replication machinery are being developed as pandemic preparedness tools, offering potential treatment options for novel respiratory viruses before pathogen-specific therapies can be developed. Host-directed antiviral therapies that target cellular pathways exploited by multiple virus families represent an emerging approach that could provide broad-spectrum activity with a higher barrier to resistance development. These antiviral programs require sites with virologic monitoring expertise, treatment discontinuation safety protocols for HBV studies, and rapid-enrollment capabilities for respiratory virus treatment studies that must capture patients during acute infection.
Novel Antibiotics & AMR Solutions
The antibiotic pipeline, while chronically underfunded relative to the public health threat of AMR, is producing innovative therapeutic approaches that go beyond traditional antibacterial mechanisms. Siderophore cephalosporins exploit bacterial iron uptake pathways to deliver antibiotics directly into resistant gram-negative organisms, bypassing porin-mediated resistance mechanisms. Bacteriophage therapy — the use of bacteria-specific viruses to lyse resistant pathogens — is advancing through clinical development for chronic infections and biofilm-associated disease where conventional antibiotics fail. Anti-virulence strategies that target bacterial toxin production or quorum sensing rather than bacterial growth offer a fundamentally different approach that may avoid the selection pressure driving resistance emergence. These novel antibiotic programs often require complex study designs including superiority and non-inferiority comparisons, pathogen-specific enrollment strata, and clinical outcome assessments that include microbiologic eradication endpoints alongside traditional clinical cure measures.
Vaccine Platform Innovation
The mRNA vaccine platform validated during the COVID-19 pandemic is now being applied to an expanding array of infectious disease targets. RSV mRNA vaccines are advancing through Phase III development for older adults, with additional programs targeting maternal immunization to protect neonates and young infants. Seasonal influenza mRNA vaccines aim to replace traditional egg-based and cell-based manufacturing with a platform that enables faster strain updates and potentially improved immunogenicity. CMV mRNA vaccines represent a significant new market targeting women of childbearing age and transplant recipients. Universal influenza vaccines targeting conserved hemagglutinin stalk epitopes aim to provide broad protection across influenza subtypes, potentially reducing the need for annual reformulation. Advanced adjuvant technologies are being paired with protein-based and viral vector vaccine platforms to enhance immune responses in older adults and immunocompromised populations. These vaccine innovation programs require sites with robust immunogenicity sample processing, ultra-cold storage for mRNA products, extended follow-up capabilities for durability assessments, and the capacity to manage large-scale enrollment during seasonal recruitment windows.
Site Requirements for Infectious Disease Excellence
The infrastructure, staffing, and operational processes required to execute modern infectious disease protocols at the highest level of quality across antiviral, antibiotic, and vaccine indications.
Access to CLIA-certified microbiology and virology laboratory services including bacterial culture and antimicrobial susceptibility testing, viral load quantification by PCR, genotypic and phenotypic resistance testing, rapid molecular diagnostic panels for pathogen identification, and serologic assays for baseline immune status characterization.
Validated cold chain infrastructure with continuous temperature monitoring across refrigerated (2-8 degrees C), frozen (-20 degrees C), and ultra-cold (-80 degrees C) storage. Automated alarm systems for temperature excursion notification, backup power supply, and documented cold chain integrity protocols from product receipt through administration.
Biosafety level 2 laboratory space with certified biological safety cabinets, pathogen-specific standard operating procedures, IBC-approved protocols for specimen handling and processing, IATA-compliant packaging and shipping for category B biological substances, and trained personnel with current biosafety certification.
Research pharmacy with temperature-controlled storage for investigational antivirals, antibiotics, and vaccines. Intravenous antibiotic preparation and administration capability, oral antiviral dispensing with adherence monitoring, PK sampling support infrastructure, and drug accountability systems compliant with antimicrobial stewardship documentation requirements.
Established relationships with community-based organizations, HIV clinics, public health departments, and primary care networks. Community advisory board engagement for vulnerable population studies, multilingual recruitment materials, culturally competent research staff, and transportation assistance programs that reduce access barriers for underserved communities.
Board-certified infectious disease physician investigators with clinical trial experience, research coordinators trained in microbiology specimen collection and vaccine administration, ID-specialized pharmacists for PK/PD sampling and antimicrobial stewardship integration, data managers proficient in infectious disease-specific EDC systems, and regulatory coordinators experienced with DSMB coordination and vulnerable population protections.
Discuss Your Infectious Disease Program
Connect with our team to explore site capabilities, enrollment strategies, and microbiology infrastructure for your infectious disease clinical development program.