Researchers at the University of Alabama at Birmingham said a nasal spray vaccine candidate against the coronavirus showed promising lab results, triggering an immune response in the nose and lungs that could potentially prevent infection .
Scientists have studied the vaccine in animal models. Studies have shown that the vaccine stimulates a response from T cells, which help create antibodies and also attack infected cells that the virus uses to make copies of itself.
T cells have mobilized in the mucus layers of the nose and lungs, where COVID-19 usually takes hold. Troy Randall, immunology expert and senior scientist at UAB’s O’Neal Comprehensive Cancer Center, said this particular vaccine stood out from those given as injections.
“With a nasal spray, most of these T cells will stay in the nose,” Randall said. “And that’s where the virus first lands. They may therefore be able to attack it and prevent infection.
With the injections, the body develops a systemic immune response that can take more than a day to reach the first areas affected by the virus, Randall said. Laboratory studies have shown a potent “killer T cell” response that targets infected cells. The vaccine was developed by Altimmune, a company based in Maryland. The company has developed nasal spray flu vaccines in the past.
“The response of mucous T cells in the airways is believed to depend on the intranasal route of administration, and we believe it has the potential to provide additional protection against COVID-19,” according to a press release from ‘Altimmune. “The induction of a mucosal T cell response in the lungs has not been demonstrated to date with intramuscularly administered COVID-19 vaccine candidates which are currently in advanced stages of clinical development.
It is not known how long the immune response in humans will last, Randall said. Immunity in the nose and lungs tends to wear off faster than systemic immunity, which is also triggered by the nasal spray.
“That’s the million dollar question,” Randall said. “Right now we only have a few months of immunity to look at. We don’t know how long this immunity will last.
In addition to the T cell response in the nose and lungs, the nasal spray has other benefits, Randall said. It can be self-administered, requires no needles, and does not need to be refrigerated. This could facilitate distribution, especially in remote locations without quick access to medical facilities.
The preclinical results at UAB will be used in an application for human trials. If approved, the vaccine would need three study phases to test its efficacy and safety.