JUL 22, 2022 7:10 PM PDT

Researchers Say Nasal Boosters Will be Important to Stopping COVID

WRITTEN BY: Carmen Leitch

The SARS-CoV-2 virus has continued to evolve since the start of the pandemic, and we've moved down the list of variants before arriving at Omicron. Now, subvariants of Omicron are becoming dominant the world over. Scientists have said they really can't say what might come next. It seems likely that the virus will continue to evolve, potentially in a chronically ill patient. Another subvariant of Omicron may arise, but it's also possible that a new variant entirely may emerge, or a subvariant of something we've seen before, like Delta, may appear. If we are going to get ahead of the virus, we may have to develop a nasal spray, suggested new research in Science Immunology. An accompanying commentary stresses the importance of intranasal vaccines for COVID.

Cropped from a transmission electron micrograph of SARS-CoV-2 Omicron virus particles (pink) replicating within the cytoplasm of an infected CCL-81 cell (teal). Image captured at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Credit: NIAID

Previous work has shown that intranasal vaccines could be very effective, especially because that is how SARS-CoV-2 enters the body - through cells in the nasal and respiratory passages - the mucosal lining. Now, researchers have confirmed that by demonstrating that in the airways, the immune responses of people who have been vaccinated don't perform well compared to people who have been naturally infected with the virus. In the very place where the immune system should be ready to fight the virus, mRNA vaccines don't seem to be generating a robust response.

While mRNA vaccines are able to cause a general immune response, and have been effective at preventing serious illness in most people, there have been many breakthrough infections. This study helped explain why. It seems as though the immune response from mRNA vaccines stays mostly in the blood. So while antibodies are found in circulation that can fight the virus, cells that sit in the mucosal linings, where the virus is trying to cause an infection, only have a small or moderate neutralizing response.

Only unvaccinated people that had been very sick with COVID-19 attacked the virus in both the airways and the bloodstream, which the researchers noted is far from ideal.

"The Omicron variant almost completely escaped neutralization by mucosal antibodies in individuals who received mRNA vaccines and in previously infected individuals," said Jie Sun, a Professor of Medicine, among other appointments, at UVA. "Our data showed that mRNA vaccination also did not induce sufficient tissue-residing cellular immunity in the airways, another arm of our immune system to prevent the entry of the virus into our bodies."

The scientists also found a way forward, however. In a mouse model that was given an intranasal vaccine in combination with an mRNA vaccine, the immune response was vigorous in the bloodstream and in the lungs. These mice were able to attack both the original strain of SARS-CoV-2 as well as the Omicron variant, Sun said.

"Our data suggest that an intranasal vaccine-boosting strategy will be critical to protect people against emerging variants of concern," Sun noted. "The nasal vaccine provides a mucosal antigen boost to the pre-existing memory of T and B cells that direct immune response, resulting in higher cellular and humoral immunity."

Although there are intranasal vaccines in development for SARS-CoV-2/COVID-19, none have been approved for use in the US yet. Some that have already been made have shown the potential for side effects. An intranasal vaccine has been tested and approved in China, but the mucosal immunity it generates has not been evaluated yet, said Sun.

Sun's team was the first to demonstrate that the immune response to COVID-19 causes permanent lung damage in unvaccinated, hospitalized patients. They are planning to continue to study the virus and look for ways to stop it.

Sources: University of Virginia, Science Immunology

About the Author
BS
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JAN 28, 2022
Health & Medicine
The Great Resignation: How the Pandemic Gave Employees the Upper Hand in Prioritizing Mental Health
JAN 28, 2022
The Great Resignation: How the Pandemic Gave Employees the Upper Hand in Prioritizing Mental Health
In the United States and other western countries, people are leaving their jobs in record numbers. An estimated 38 milli ...
MAR 23, 2022
Immunology
Drug That Reverses Immune Aging Can Prevent COVID-19 Death
MAR 23, 2022
Drug That Reverses Immune Aging Can Prevent COVID-19 Death
As we age, parts of our bodies get old and worn out, including the immune system. That's one reason why COVID-19 has bee ...
APR 24, 2022
Immunology
COVID-19 Vaccine is Safe, Effective for Kids & Teens
APR 24, 2022
COVID-19 Vaccine is Safe, Effective for Kids & Teens
A variety of studies by different reseaech groups have now confirmed that the Pfizer-BioNTech mRNA COVID-19 vaccine is s ...
JUL 23, 2022
Drug Discovery & Development
Anti-inflammatory Compound Shows Promise in Treating Severe COVID-19
JUL 23, 2022
Anti-inflammatory Compound Shows Promise in Treating Severe COVID-19
An anti-inflammatory compound has shown promise in treating systemic inflammation and brain injury in patients with seve ...
SEP 02, 2022
Coronavirus
Omicron-Specific Booster Shots Will be Available Soon
SEP 02, 2022
Omicron-Specific Booster Shots Will be Available Soon
Soon, vaccine booster shots that are specific to the Omicron variant will be available in many countries. The new Omicro ...
SEP 16, 2022
Coronavirus
Persistent COVID Cases Seem to Encourage Viral Mutations
SEP 16, 2022
Persistent COVID Cases Seem to Encourage Viral Mutations
The majority of SARS-CoV-2 infections start to get better within several days, although infected people can shed virus a ...
Loading Comments...