Novel RSV-A challenge agent to accelerate vaccine development

SGS has unveiled a novel Respiratory Syncytial Virus (RSV) A-strain challenge agent, designed to closely mimic circulating RSV viruses and accelerate the development of vaccines and therapeutics. Manufactured under GMP and tested in humans, this is the first RSV-A challenge agent of its kind globally.

The agent was derived from a 2015 circulating strain, offering a more accurate reflection of the viruses currently responsible for severe respiratory infections in infants, older adults, and immunocompromised patients — a population that experiences millions of infections and thousands of hospitalisations annually.

Early proof-of-concept studies at SGS’s Controlled Human Infection Models (CHIM) hub in Antwerp demonstrated the agent’s potency. Twelve healthy volunteers were inoculated under controlled conditions, with 100% of the evaluable participants showing detectable RSV infection and most developing clinically relevant symptoms. These results confirm the agent’s suitability for human challenge studies and open the door to optimising dosing for future trials.

Jelle Klein, Medical Director at SGS, said: 

“This RSV-A challenge agent bridges the gap between preclinical research and human data, enabling faster, high-quality evaluation of potential vaccines and treatments. It positions SGS as a key partner for pharmaceutical and biotech companies tackling RSV.”

The new challenge agent expands SGS’s CHIM portfolio in Europe, which already includes influenza, rhinovirus, and malaria models. By offering a reliable, clinically validated RSV model, SGS aims to streamline early-phase vaccine and therapeutic testing, helping innovators accelerate their path to market.

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