New intranasal vaccine deemed hopeful

A needle-free mucosal bacteriophage T4-COVID-19 vaccine is active against SARS-CoV-2 infection; new research has shown.

The Food and Drug Administration authorised COVID-19 vaccines we use now, delivered through an intramuscular injection in two or more doses and have been shown to reduce severe illness and the risk of death. Still, they, unfortunately, do not prevent viral transmission or induce efficient mucosal immunity. However, the nasal vaccines may be able to go a step further by blocking infections entirely at the site of entry.

In the new study, senior study authors Venigalla B. Rao, PhD, and Ashok K. Chopra, PhD, and their colleagues report the first non-infectious, phage T-4-based needle and adjuvant-free mucosal vaccine. Both authors are elected peers of the American Academy of Microbiology.

In experiments conducted with mice, two doses of the phage COVID-19 vaccine were intranasally administered twenty-one days apart; this resulted in the mice maintaining strong systemic humoral and cellular immune responses and robust mucosal activity.

Nasal sprays are most often used in children and teenagers due to the lack of needles. However, in the case of SARS-CoV-2, their ability to prevent infection and even transmission could mean that there would be an advantage in distributing them to the broader population.

Scientists do not know much about mucosal immunity, and this can therefore mean that nasal vaccines are problematic. In practice, it can be troublesome to ensure that a person gets the correct dose and doesn’t swallow or sneeze out the vaccine, and the vaccine must still get past the mucus.