WHAT if the next COVID-19 vaccines didn't need to be administered with needles and syringes? Researchers around the world are working intensively on developing vaccines that can be administered nasally or orally.


The marathon task of developing COVID-19 vaccines continues. And while most are administered by injection, a few groups of researchers are looking at nasal solutions, administered through the nose.


But what are the advantages of this kind of solution? "The upper respiratory tract is an initial site of SARS-CoV-2 infection and, for many individuals, remains the primary site of virus replication," explain researchers and immunologists in the Science Advances journal. "An ideal COVID-19 vaccine should reduce upper respiratory tract virus replication and block transmission as well as protect against severe disease."


In the journal Science, researchers from the University of Alabama at Birmingham are also advocating the benefits of nasal spray. According to them, it could even be more effective, since "immunoglobulin A (IgA) and resident memory B and T cells in the nasal passages and upper airways are elicited by intranasal vaccination and prevent infection and reduce virus shedding. Serum IgG elicited by intramuscular vaccination transudates into the lungs and prevents pulmonary infection, but allows infection in the nasal passages and virus shedding."


Testing underway

While no such covid-19 vaccine is marketed to date, tests and experiments are gathering pace. Research into one vaccine, published in the journal Science Advances by US scientists, shows it has been successfully tested on ferrets and mice. This vaccine is expected to be tested on 80 healthy adults in the coming months.


In France, researchers at the University of Tours are also working on a nasally-administered vaccine. The 20 or so researchers who have been working on the project since last summer hope to start testing the vaccine on humans at the end of 2021, or early in 2022.


A total of six nasal spray vaccine projects are being studied worldwide. This method of administration is still relatively unusual for vaccines, even though it has been used in certain countries, like the United States, for flu vaccines.


Popping a vaccine pill?

Other solutions are being explored to facilitate the use of COVID-19 vaccines around the world. In a global first, a clinical trial for an orally administered vaccine has just been launched in Israel, according to the Jerusalem Post. Half of the 24 volunteers will receive a single dose, while the other 12 will receive a second dose. This first trial has just entered Phase 1, and is designed to measure safety and antibody levels and other immunity indicators following the vaccine.


For the moment, this orally administered vaccine has shown its effectiveness in several animal trials, even against the Delta variant. If commercialized, it is likely to be used primarily in developing countries, where vaccination rates are low due to the logistical challenges of using currently available vaccines.