The CDMO Naobios has announced a new partnership with the testing and certification company SGS to manufacture a Respiratory Syncytial Virus (RSV) challenge agent for use in Controlled Human Infection Model (CHIM) studies conducted by SGS.
The Human Viral Challenge Agent (HVCA), produced under current Good Manufacturing Practices (cGMP), is derived from a 2015 A-strain isolate that closely mirrors circulating RSV strains. It provides valuable data on vaccine efficacy and immune responses.
Why this matters
Respiratory Syncytial Virus (RSV) is one of the leading causes of severe respiratory infections among infants, immunocompromised adults and elderly individuals.
It leads to approximately 64 million infections and 3.6 million hospitalisations worldwide each year.
As health systems continue to grapple with the challenges posed by annual RSV outbreaks, the demand for the rapid development of effective vaccines and treatments has never been more urgent.
Naobios has already completed the development and production of multiple HVCAs for global studies. These agents are used in Controlled Human Infection Model (CHIM) trials, where healthy volunteers receive a carefully measured dose of a pathogen under strict ethical and safety oversight to evaluate vaccines or treatments.
These trials enable early and cost-effective assessments of RSV vaccines, aiding the rapid development of effective and affordable options.
In October 2025, 12 healthy participants were inoculated with the RSV A-strain challenge agent at the SGS Clinical Pharmacology Unit in Antwerp, Belgium, resulting in a 100% attack rate, with only mild and self-resolving symptoms observed.
"In response to the growing use of CHIM studies, we have invested to extend our range of services, enabling us to meet the critical needs of clients worldwide," said Eric Le Forestier, General Manager of Naobios.
This partnership with SGS demonstrates that Naobios continues to be a key global player and first-choice partner for viral challenge agent manufacturing in accordance with cGMP.
Naobios has a strong track record in HVCA, producing 36 GMP batches for vaccines, including SARS-CoV-2, RSV, hMPV and influenza.
They utilise an innovative approach to accelerate vaccine development, with clinical evaluations conducted by specialised CHIM centres such as SGS.
"Controlled Human Infection Models are a powerful tool to de‑risk and accelerate early vaccine development when conducted under the highest scientific, ethical and biosafety standards," said Jelle Klein, Medical Director, SGS CPU.
"Following GMP manufacturing of the RSV challenge agent by Naobios, SGS was responsible for the full clinical validation within a CHIM setting, including study design, clinical execution, safety oversight and virological assessments, enabling the generation of robust, decision‑enabling data for RSV vaccine and antiviral development."
The clear step-by-step approach of Naobios provided us with a solid overview on which assessments were performed, when they were completed and what the results were.
"This provided us with full oversight of the process, allowing us to adjust clinical timelines based on emerging data."