UPDATE 2-Astra-Sanofi's RSV therapy 90% effective against infant hospitalizations, CDC study shows

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March 7 (Reuters) - AstraZeneca and Sanofi's antibody therapy was 90% effective in protecting infants from hospitalizations associated with respiratory syncytial virus (RSV), a U.S. CDC study showed.

The data is the first real-world evidence of effectiveness of the therapy, nirsevimab, in protecting infants against RSV-related hospitalization in their first season of potential exposure to the virus.

The therapy, branded as Beyfortus, won the U.S. health regulator's nod in July 2023.

Although the data available for analysis is limited, CDC said the early estimates support the current recommendation of use in infants. In August, the CDC had recommended the use of the therapy in infants below eight months of age born during or entering their first RSV season, as well as in children aged 8-19 months who remain vulnerable to severe RSV disease through their second season.

The study looked at nearly 700 infants who were hospitalized with acute respiratory illness, from October 2023 through February 2024. Of those, 8% infants received the therapy more than or at 7 days before experiencing symptoms.

The results also reflect a shorter surveillance period due to the introduction of the product in August 2023, the agency said, as well as limited supply of the therapy.

With increasing availability, the CDC said it will continue to assess the effectiveness of the therapy over an entire season.

Pfizer's maternal RSV vaccine, Abrysvo, is also available to prevent for young infants.

RSV, a common respiratory virus, is a leading cause of hospitalizations in infants. (Reporting by Sriparna Roy in Bengaluru; Editing by Shounak Dasgupta and Krishna Chandra Eluri)