US biotech company Moderna on Tuesday announced positive interim trial results for its vaccine against respiratory syncytial virus (RSV) in adults over the age of 60.
There are no jabs currently available for the virus, which is a top cause of lower respiratory diseases, commonly leading to bronchiolitis in children and pneumonia in the elderly.
However numerous vaccines and treatments are under development, most notably by Moderna's rival Covid-19 vaccine maker Pfizer.
Moderna's vaccine was found to be nearly 84 percent effective against RSV-linked diseases in Phase III trials -- the final stage of human testing -- the firm said in a statement.
The trial of the vaccine, which uses the new mRNA technology from Moderna's Covid jab, involves some 37,000 adults over 60 in 22 countries including the United States.
The company released the findings of an interim analysis, which has not been peer-reviewed.
In the placebo group, there were 55 cases of RSV-linked lower respiratory tract disease with at least two symptoms, compared to nine in the group that received the vaccine, it said.
The vaccine had no serious side effects, the company added.
Moderna plans to apply for regulatory approval for the vaccine in the US, Europe and other regions in the coming months.
This could make it available for the RSV season in the Northern Hemisphere's winter this year, Moderna's chief medical officer Paul Burton told AFP.
The company is also testing the vaccine for use in children, but those trials are still at the first phase.
In high-income countries, RSV caused 5.2 million cases of severe disease among adults over 60 in 2019, Moderna said.
Up to 30,000 elderly patients die every year in G7 countries due to the virus, Burton added.
He said that the number of doses required for Moderna's vaccine was yet to determined.
The positive results come after Pfizer announced in December that its own RSV vaccine for over-60s was granted priority review status by the US Food and Drug Administration.
The previous month, Pfizer said another of its RSV vaccines, which is given to pregnant mothers, was effective at protecting newborns.
Also in November, the European Union approved a preventative treatment which works similarly to a vaccine made by AstraZeneca and Sanofi which has been shown to prevent severe illness from RSV in infants.
When asked about other RSV vaccines being developed by Moderna's rivals, Burton said "it's good news".
"The public has gone seven decades with nothing" to fight the virus, and soon could have multiple options, he said.
Moderna is also looking at whether the RSV jab can be combined with Covid and even influenza vaccines, after soaring cases of all three in recent months was dubbed a "tripledemic".