Creeping toward Effective Antiviral Agents for RSV Infection

This editorial reviews a phase 3 trial of ziresovir—a fusion inhibitor—for infants hospitalized with respiratory syncytial virus (RSV) in China. Ziresovir significantly improved clinical scores and reduced viral load compared to placebo, especially in infants under 6 months. Drug resistance was observed in 9%, though without viral rebound. The author cautions that the Wang bronchiolitis score, used to measure outcomes, lacks full validation and its translation to concrete clinical benefits remains uncertain. Early treatment initiation may be critical given declining viral loads after symptom onset. Ziresovir may complement maternal vaccination and monoclonal antibody strategies, with potential relevance for severely immunosuppressed patients.

This editorial reviews a phase 3 trial of ziresovir—a fusion inhibitor—for infants hospitalized with respiratory syncytial virus (RSV) in China. Ziresovir significantly improved clinical scores and reduced viral load compared to placebo, especially in infants under 6 months. Drug resistance was observed in 9%, though without viral rebound. The author cautions that the Wang bronchiolitis score, used to measure outcomes, lacks full validation and its translation to concrete clinical benefits remains uncertain. Early treatment initiation may be critical given declining viral loads after symptom onset. Ziresovir may complement maternal vaccination and monoclonal antibody strategies, with potential relevance for severely immunosuppressed patients.