Infectious Disease Clinical Trials Update: Week 23, 2026

Published June 5, 2026 — 5 trials covered

By Victor Lafforgue, Founder of TrialsAlert. Blog posts are AI-drafted from ClinicalTrials.gov source data and reviewed by the editorial team. See our editorial policy for details.

A Multicenter Study to Evaluate Safety and Immunogenicity of a Live-attenuated Chikungunya Vaccine in Adolescents

This Phase 3 trial evaluated a live-attenuated vaccine designed to protect adolescents aged 12 to under 18 years against chikungunya, a virus spread by mosquitoes that can cause fever and joint pain. Conducted in Brazil with over 750 participants, the study’s results provide important information on the vaccine’s safety and ability to trigger an immune response. If this vaccine is approved, it could become a valuable tool to prevent chikungunya infections in regions where the virus is common.

Study to Compare an Oral Weekly Islatravir/Lenacapavir Regimen With Standard of Care in Virologically Suppressed People With HIV-1

This Phase 3 study tested a new oral tablet combining two drugs, islatravir and lenacapavir, taken once a week by people living with HIV-1 who already have their virus under control. The goal was to see if this weekly pill could be as effective as the current daily treatments, making it easier for patients to stick to their medication schedule. While the study is still active and not recruiting new participants, results expected after 48 weeks of treatment will help determine if this simpler option can be offered to patients in the future.

A Study on the Immune Response and Safety of an Investigational Chickenpox Vaccine When Given to Healthy Children 12 to 15 Months of Age

This ongoing Phase 3 trial is testing a new vaccine for chickenpox in healthy toddlers between 12 and 15 months old who have not had chickenpox or any prior vaccination against it. By comparing the immune response and safety of this investigational vaccine, the study aims to provide an additional choice that may offer consistent protection for young children. The trial is recruiting participants in several countries, and its findings could influence future vaccination recommendations for chickenpox.

A Study to Learn About COVID-19 RNA-Based Variant-Adapted Vaccine Candidate(s) Against SARS-CoV-2 in Participants Ages 12 Through 64 Years Considered at Higher Risk of Severe COVID-19, and Participants Ages ≥65 Years

This Phase 3 trial is evaluating an updated RNA-based COVID-19 vaccine designed to target newer variants of the virus. It focuses on people aged 12 and older who are at higher risk of severe illness from COVID-19. Conducted across multiple locations in the United States, the study aims to determine whether this variant-adapted vaccine can offer better protection and reduce the chances of severe disease. The trial lasts about six months and could help guide future vaccine strategies as the virus continues to evolve.

Study of Monovalent and Bivalent Recombinant Protein Vaccines Against COVID-19 in Adults 18 Years of Age and Older

This large Phase 3 trial tested new COVID-19 vaccines made from recombinant proteins, including both monovalent and bivalent formulations, in over 23,000 adults aged 18 and older. The study also assessed these vaccines as booster doses to improve protection against COVID-19. By offering additional vaccine options, these findings may expand choices for adults seeking to maintain immunity against the virus and its variants.

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