A study shows that intranasal administration of AstraZeneca’s COVID-19 vaccine reduces viral shedding and prevents infection in animal models.
Since the start of the pandemic, researchers have been hard at work, developing vaccines against the novel coronavirus. The months of extensive research has resulted in multiple effective COVID-19 vaccines. A huge majority of the current vaccines are given via intramuscular injections. However, a recent study from the team at the University of Alabama suggests that the intranasal administration COVID-19 vaccine might be more effective at preventing the spread of SARS-CoV-2.
Immunologists Frances Lund and Troy Randall argue that the novel coronavirus sheds from the oral and nasal passages. Therefore, an intranasal vaccine is a better option than intramuscular injections. To test this theory further, a team of researchers compared the effect of the two vaccination routes on viral shedding. They administered the AstraZeneca-Oxford vaccine to animal models of hamsters and monkeys.
Human Trials in Progress
According to the results published in Science Translational Medicine, intranasal vaccination led to decreased virus load in swabs. Thus, suggesting lower viral shedding in animals given the intranasal vaccines. Moreover, unlike intramuscular vaccines, it caused both a strong mucosal and humoral immune response in the animals.
Recently a leaked CDC document revealed that vaccinated individuals infected with the delta coronavirus variant can shed the virus at a similar rate as an unvaccinated individual. Moreover, the rise of coronavirus variants has led to breakthrough infections among vaccinated people. Therefore, researchers suggest the use of intranasal vaccines in reducing transmission amid the evolving viral strains. However, intranasal vaccines provide a shorter period of immunity as compared to intramuscular injections.
The results of the study highlight the need for further investigation of the vaccination route and its effect in humans. According to the study authors, a team at the University of Oxford has already begun phase 1 clinical trials of intranasal AstraZeneca vaccine.
Neeltje van Doremalen et al, Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models, Science Translational Medicine (2021). DOI: 10.1126/scitranslmed.abh0755
Frances E. Lund et al, Scent of a vaccine, Science (2021). DOI: 10.1126/science.abg9857