Story at a glance
- A nasal vaccine could be another weapon in the arsenal against COVID-19.
- Early research has shown promising results in terms of efficacy.
- Recent research published in Science Immunology suggests coupling mRNA vaccines with an intranasal booster vaccine can provide much stronger protection against the virus in the airways where it enters the body.
As Americans continue to live with the ongoing COVID-19 pandemic — and a highly contagious version of the virus that is currently circulating nationwide — researchers and public health officials are looking onward to a new generation of vaccines.
Just last week, federal health officials and vaccine manufacturers gathered for a White House summit on the future of COVID-19 vaccines, agreeing there’s a need for innovative vaccines that are more effective in preventing infections and protecting against potential variants.
The summit occurred as the U.S. is undergoing another surge in coronavirus cases, driven by two new types of the omicron variant, BA.4 and BA.5, both subvariants of the highly contagious omicron variant. Early evidence shows the subvariants are better at evading prior immunity, meaning people with immunity either from vaccines or past COVID infection are susceptible to infection.
National Institute of Allergy and Infectious Diseases (NIAID) Director Anthony Fauci during the summit advocated for “two pillars” of the next generation of vaccines, which includes the development of a pan-coronavirus vaccine to help curb the proliferation of variants and a nasal vaccine that can be inhaled instead of injected.
Currently, most studies of intranasal COVID-19 vaccines are in the preliminary stages. But early research has shown promising results in terms of efficacy.
A viable nasal vaccine may be key in preventing the spread of the virus. While current mRNA COVID-19 vaccines induce robust immunity in the blood, preventing severe disease, research has suggested the antibody response in the airways where the virus enters the body may be lacking, particularly when it comes to the omicron sublineage.
Recent research published in Science Immunology suggests coupling mRNA vaccines with an intranasal booster vaccine can provide much stronger protection against the virus where it enters the body, thus limiting the spread and preventing breakthrough infections.
“The omicron variant almost completely escaped neutralization by mucosal antibodies in individuals who received mRNA vaccines in previously infected individuals,” Jie Sun, a professor of medicine at the University of Virginia and one of the authors of the study, said.
“We think the robust antibody responses in the respiratory tract would neutralize the virus immediately upon viral entry when the individual contracts the virus, preventing the establishment of viral infection and subsequent passing of the infection to others.”
For the study, researchers showed that mice given an mRNA vaccine experienced a good antibody response in the blood but not very good mucosal immunity. However, when given a nasal booster, researchers observed a “very robust” mucosal immunity response against all SARS-CoV-2 variants tested. Sun said using the vaccines in tandem has the potential to stop the establishment of a viral infection immediately.
“Because most of the population already got the mRNA vaccine or has been exposed or contracted COVID, all we need is maybe to provide a nasal booster to really attract this preexisting immunity to the mucosal surface. So it’s like we’d have a guy at the door to immediately stop any bad guy from coming into the building,” Sun said.
But still, Sun cautioned that much more research needs to be done, and it’s too early to say whether the results observed in animal models will translate to humans.
Plenty of nasal vaccine candidates are under development, but most studies right now are still at an early phase, and there have been very few human trials. Sun said it will likely be a couple of years before a nasal vaccine is made available to the public.
“We hope it’s going to work in humans. No one knows right now.”