Vaccines and Drugs in the Pipeline for RSV

Reuters staff

November 21, 2022

(Reuters) - There are no approved vaccines and only one drug in the United States for respiratory syncytial virus (RSV), a common respiratory virus that usually causes mild, cold-like symptoms but can also lead to serious illness and hospitalization.

Sanofi SA and AstraZeneca Plc's drug nirsevimab recently became the second to get Europe's approval to prevent RSV infections in infants, after Swedish drugmaker Orphan Biovitrum's Synagis. Nirsevimab does not have U.S. approval yet.

There are a handful of companies developing drugs and vaccines for the infections, some of which could become available as soon as early next year:


The company is developing an RSV shot for older adults as well as for infants when given to expectant mothers, and plans to apply for approval for the maternal vaccine by year-end.

Earlier in November, Pfizer Inc reported that its RSV vaccine was 81.8% effective in a late-stage study in preventing severe infections in infants when given to expectant mothers. However, the vaccine did not meet the study's second main goal of preventing less severe respiratory illness.

The vaccine in August was shown to be 85.7% effective in a different trial among participants aged 60 and above with three or more symptoms.


GSK Plc's vaccine was 82.6% effective against RSV infection in a late-stage study involving adults aged 60 and over, data showed in October.

U.S. and Europe authorities are yet to approve the vaccine. The U.S. Food and Drug Administration (FDA) is expected to announce the decision on the vaccine's marketing application by May next year. If approved, the shot is expected to generate billions in sales for the British drugmaker.


Earlier this month, Sanofi SA and AstraZeneca Plc gained the European Commission's marketing authorization for their antibody treatment nirsevimab for preventing disease caused by RSV in infants.

In March, nirsevimab showed an efficacy of 74.5% against some types of lower respiratory tract infections compared with a placebo in infants in a late-stage study. Monoclonal antibodies are synthetically manufactured copies of the human body's natural infection-fighting proteins and are already being used to treat some types of cancers.

Nirsevimab received a breakthrough therapy designation in the United States and is under review by the FDA.


Johnson & Johnson began a late-stage study of its RSV vaccine in 2021 for adults aged 60 years and older, with data expected by the end of this year.


COVID vaccine-maker Moderna Inc began a late-stage trial of its RSV vaccine earlier this year in people aged 60 years and above, based on messenger RNA (mRNA) technology used for the development of its coronavirus shot.

Interim data from the study is expected this winter.


Merck & Co Inc is currently conducting a late-stage study testing its experimental antibody drug clesrovimab to prevent RSV infections in infants and children. It expects to complete the trial in 2024.


Denmark-based Bavarian Nordic in April began a late-stage trial for its RSV vaccine in volunteers aged 60 years and older. Study results are expected by mid-2023.

(Reporting by Raghav Mahobe and Nandhini Srinivasan in Bengaluru; Editing by Devika Syamnath)