A monoclonal antibody to protect all babies against respiratory syncytial virus could be approved overseas within months, with Australia likely to follow, say infectious diseases specialists.

Trials of the agent, nirsevimab, shows a single IM injection effectively immunises infants against respiratory syncytial virus (RSV), which is one of the leading causes of hospitalisation for bronchiolitis and pneumonia.

Nirsevimab is the first of 33 RSV prevention candidates to have completed phase III trials, following at least 20 years of research trying to find a successful vaccine, says paediatric immunologist Professor Peter Richmond, head of the vaccine trials group at the Telethon Kids Institute in Perth.

“We recently completed phase III studies on nirsevimab here in Perth, and there have been positive results reported from the Northern Hemisphere pre-COVID-19, so it is expected to be licensed for use as the very first RSV prevention treatment in the US/Europe by late 2022 or early 2023,” he said in a statement.