Nasal Covid-19 vaccine: Animal study shows effective immunity, zero virus spread

Researchers have discovered that a single-dose experimental vaccine administered nasally offered 100 per cent efficacy against Covid-19 in mice and blocks the virus’ animal-to-animal transmission. The study was conducted by a joint team of the University of Georgia and the University of Iowa and the findings were published in Science Advances.

Unlike traditional vaccines that are injected into the body, this vaccine is administered nasally through a spray. It requires only a single dose and can even be stored for up to three months at normal refrigerator temperatures. This can be seen as a potentially huge development as the absence shortage of proper cold storage facilities for vaccines that are currently in use has been one of the main reasons for several developing economies, especially those in Asia and Africa, lagging behind. The nasal nature of the vaccine also makes it easier to administer, especially to those with a fear of needles.

A harmless parainfluenza virus 5 is used by the experimental vaccine to deliver the spike protein of the SARS-CoV-2 into cells. The vaccine prompts an immune response in these cells. The study also showed that the vaccine was successful in producing localised immune response that involved cellular immunity and antibodies. This protected the mice from even fatal SARS-CoV-2 doses. The experimental vaccine also prevented ferrets from the infection and disease. It also appeared to block Covid-19’s transmission from infected ferrets to uninfected and unprotected cage-mates.

Several companies, including Bharat Biotech and Canada-based Senotize, are trialling nasal vaccines. Russia has also tested a nasal version of its Covid-19 vaccine. Intranasal vaccines have several advantages with experts believing that such immunisation would replicate natural immunity more closely and reduce both virus transmission and infection. However, such vaccines are incapable of producing long-lasting and effective immunity and may result in the immunity waning faster.