Naobios, SGS partner to manufacture Respiratory Syncytial Virus challenge agent

Naobios and SGS partnered to manufacture a Respiratory Syncytial Virus (RSV) challenge agent for use in controlled human infection model (CHIM) studies supporting vaccine development.

Contract development and manufacturing organization Naobios developed and produced the human viral challenge agent under current Good Manufacturing Practice (cGMP) conditions using a 2015 RSV A-strain isolate designed to closely mirror currently circulating strains, according to the announcement. The agent is intended for use in CHIM studies in which healthy volunteers receive a controlled dose of a pathogen to evaluate vaccines or treatments.

In October 2025, 12 healthy volunteers were inoculated with the RSV challenge agent during a study conducted at the SGS clinical pharmacology unit in Antwerp. The study reported a 100% infection rate with mild, self-resolving symptoms, according to Naobios.

The company said it has manufactured and released 36 GMP batches of human viral challenge agents, including those for SARS-CoV-2, RSV, human metapneumovirus and influenza. These agents are used in controlled clinical trials designed to generate early data on vaccine efficacy and immune responses.

“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,” Eric Le Forestier, general manager of Naobios, said in a statement.

Jelle Klein, medical director of the SGS clinical pharmacology unit, said CHIM studies can help accelerate early vaccine development when conducted under strict scientific, ethical and biosafety standards.

RSV is a leading cause of respiratory infection in infants, older adults and immunocompromised patients and contributes to an estimated 64 million infections and 3.6 million hospitalizations worldwide each year, according to Naobios.