RSV is an enveloped RNA virus that is highly prevalent and infectious, which causes respiratory tract illness, especially in vulnerable populations such as children, the elderly and the immunocompromised.
RSV infection is the number one cause of LRTI in young children worldwide, infecting 90% of children under two years old with approximately 3.3 million infected and hospitalized children globally each year. In 2020, incidence of severe RSV infection in children under five years old reached 34.6 million and 3.0 million globally and in China, respectively. RSV is also estimated to infect 5.5% of adults aged 65 years or above globally each year, as their immune system gradually deteriorates due to aging. In 2020, incidence of severe RSV infection in adults aged 65 years or above reached 4.9 million and 1.2 million globally and in China, respectively.
Despite decades of clinical efforts, no RSV vaccine or effective treatments specifically targeting RSV has demonstrated efficacy or been approved globally. Ziresovir, a novel drug that targets the RSV F protein, is the first RSV drug worldwide to enter phase III clinical trial in hospitalized infants and young children and is currently in phase III registration trial in pediatric patients, with substantial near-commercial opportunities. Due to its clinical and safety profile, ziresovir is the first non-oncology drug to receive “breakthrough designation” from the NMPA.