Dutch researchers working on nose spray that can prevent flu infections

Dutch and American scientists are working on a nasal spray containing a broad-spectrum antibody against influenza that is proving effective against a wide variety of strains. According to the researchers from the Leyden Laboratories in the Netherlands and Harvard University in the United States, the antibodies can capture flu viruses in the nasal cavity before they make their way into the body, NRC reports.

The nose spray is still in the experimental phase, but it has proven effective in preventing infection in mice and monkeys. And initial human trials showed that it was safe.

The current best weapon against influenza, which kills approximately 4,700 people per year in the Netherlands and 650,000 worldwide, is the vaccine, which must be annually updated and, on average, is only about 30 percent effective in preventing infection, according to the Dutch College of General Practitioners. The researchers think their nasal spray will have a much better track record.

They’ve discovered a broad-spectrum antibody, CR9114, which targets a segment of the surface protein hemagglutinin (H), which is common to many influenza virus variants. Influenza viruses use this protein to attach to host cells. In laboratory tests, the antibody was able to recognize several subtypes of H, including those from influenza viruses that infect humans and some that infect animals.

This means that, potentially, the nasal spray can protect against new seasonal influenza variants without having to be updated annually, as well as unexpected new strains that jump from animals. For example, scientists have feared for years that the H5N1 bird flu virus, which is already circulating in wild mammals and dairy cattle, might one day adapt its way into spreading to humans.

A big advantage of the nasal spray is that the antibodies intercept the flu virus at the point where it enters the body. The 143 healthy human participants who participated in the study tolerated the spray well at various tested doses. Twice-daily administration proved sufficient to maintain a high antibody count in the nose. Follow-up studies with larger groups will investigate how well the spray protects humans against flu infections.