Bold claim: a Quebec-developed vaccine could soon shield young children from three common respiratory diseases, including the feared RSV.
A team at Université Laval is advancing a vaccine that may one day protect kids from three illnesses, with RSV as a key target. If approved, it would become the first vaccine against respiratory viruses designed specifically for children aged six months to five years.
“Right now, there are no vaccines approved for these diseases in young children,” notes Guy Boivin, a professor of medicine at Université Laval and a researcher at the CHU de Québec – Laval University Research Center. He adds that while RSV vaccines exist for older adults, none are available for very young children.
Because babies born in winter and spring currently rely on antibodies to guard against RSV—and that protection lasts only about six months—Boivin emphasizes the need for a longer-lasting solution. “We want a vaccine that provides extended protection, ideally reducing the need for annual shots like influenza,” he explains.
The researchers began by creating a “bivalent” vaccine targeting human metapneumovirus and RSV, two pathogens responsible for many cases of bronchiolitis and pneumonia in young children each year. This year, they achieved a breakthrough by adding proteins from a third virus, transforming the formulation into a “trivalent” vaccine.
In mouse studies, the experimental vaccine elicited a strong antibody response and prevented the virus from multiplying in the lungs. Boivin highlights that the vaccine could cover about 95% of bronchiolitis causes and over 80% of pneumonia-related deaths among young children.
Independent confirmation came from a National Institutes of Health study in the United States using cotton rats, which reported similar promising results.
“We achieved very good outcomes,” Boivin states. “No virus was detected in the lungs after vaccination and subsequent exposure to a substantial viral load, which is very encouraging.”
The Quebec team’s vaccine platform uses a modified human metapneumovirus strain that has had the gene linked to inflammation in young children removed, creating an attenuated virus. They then attached the RSV surface protein, followed by proteins from the third virus.
A notable advantage of this vaccine candidate is nasal administration. Beyond avoiding needles, the nasal route is hoped to foster immunity at the site where infections enter, potentially intercepting viruses as soon as they arrive.
Boivin explains: “It builds a barrier at the entry point—the nose—so, after vaccination, viruses may struggle to penetrate because this protective wall has been established.”
Developing vaccines for mucosal respiratory viruses remains a significant challenge, even with substantial ongoing efforts. The researchers describe their candidate as a promising option for protecting children, at-risk young adults, and older adults who may require tailored vaccination schedules and treatments.
The team also plans to explore potential usefulness in populations beyond young children, while cautioning that the product would not be suitable for immunocompromised individuals or pregnant women, for whom even an attenuated virus could pose risks.
The latest findings appear in the journal npj Vaccines.
— This report by La Presse Canadienne was translated by CityNews
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