Vaccine developed in Quebec offers protection from 3 diseases to children

A vaccine currently being developed by a team at Université Laval could one day protect young children from three different diseases, including the dreaded respiratory syncytial virus (RSV).

It would be the first-ever vaccine against respiratory viruses for children aged six months to five years.

“At this time, it’s important to note that there are no vaccines approved for these diseases in young children,” said Guy Boivin, professor of medicine at Université Laval and a researcher at the CHU de Québec – Laval University Research Center.

“For RSV, there are vaccines that are approved for the elderly, but not for young children.”

As a result, he added, for the past year or two, babies born in the winter or spring have been given antibodies to protect them from RSV, but this protection lasts for a maximum of six months. “So that’s where we need to vaccinate, and if possible, vaccinate for a long period of time, because we don’t want to have to vaccinate every year, for example, as we do for influenza,” Boivin explained.

He and his colleagues first developed a “bivalent” vaccine to protect children from human metapneumovirus and respiratory syncytial virus, which cause numerous cases of bronchiolitis and pneumonia in young children every year.

Then, this year, they succeeded in incorporating proteins from a third virus, making it a “trivalent” vaccine.

In tests on mice, the experimental vaccine triggered a strong antibody response and blocked the virus from multiplying in the lungs. Boivin said the vaccine “covers 95% of the causes of bronchiolitis (…) and over 80% of the causes of pneumonia deaths in young children.”

An independent study conducted by the National Institutes of Health in the United States using cotton rats yielded the same results.

“We had very good results,” said Boivin. “No virus was detected in the lungs after immunization, followed by a ‘challenge’ with a significant amount of virus, so we are very, very happy.”

The vaccine platform developed by Quebec researchers is based on a strain of human metapneumovirus that has been modified to remove the gene associated with significant inflammation in young children who contract it, known as an “attenuated virus.”

The team then added the surface protein of RSV, the leading cause of pneumonia and bronchiolitis in young children, to this platform, followed by the proteins of a third virus.

The vaccine currently under development has the advantage of being administered through the nose. Not only does this method avoid needles, but it is also hoped that it will develop immunity directly in the nose, so that viruses can be intercepted and neutralized as soon as they knock on the door.

“It creates a wall,” Boivin explained. “It’s a barrier to the virus entering because it comes in through the nose. So, after vaccination, viruses will not be able to penetrate adequately because of this barrier that will have been built, so to speak, by the vaccination.”

The development of new vaccines against mucosal respiratory viruses remains a major challenge, “despite considerable efforts in this area,” the study authors write.

The vaccine candidate they have developed, they add, “could be a promising new option for protecting children, at-risk young adults, and older adults who need specific strategies tailored to their vaccine response, schedule, and treatment regimen.”

Boivin’s team intends to verify whether the vaccine could be useful for populations other than young children, but the researcher points out that the product would not be appropriate for immunocompromised individuals or pregnant women, for whom even an attenuated virus could be dangerous.

The findings of the new study were published in the journal “npj Vaccines.”

–This report by La Presse Canadienne was translated by CityNews