Cell: Single dose of ChAd vaccine protects the upper and lower respiratory tracts from SARS-CoV-2 infection.

AUGUST 26, 2020 /--- In a new study, researchers at the University of Washington's St. Louis School of Medicine have developed a vaccine for the SARS-CoV-2 virus, known as ChAd, that can be effectively prevented in mice sensitive to the new coronavirus through a nose injection.
results were published online August 19, 2020 in the journal Cell, under the title "Single-single-dose intranasal ChAd vaccine protects upper and lower respiratory trace ST SARS-CoV-2".
from Cell, 2020, doi:10.1016/j.cell.2020.08.026.
, unlike other COVID-19 vaccines under development, the vaccine is delivered through the nose, which is often the site of the initial infection.
the new study, the authors found that this nasal delivery pathway produces a strong immune response throughout the body, but is particularly effective in the nose and respiratory tract, preventing SARS-CoV-2 infections from take root in the body.
"We were surprised to find that there is a strong immune response in the inner walls of the nose and upper respiratory tract, and that it is well protected against infection with the virus," said Co-author Dr. Michael S. Diamond, a professor of molecular microbiology and professor of pathology and immunology at the University of Washington School of Medicine in St. Louis.
the mice were well protected from the disease.
in some of these mice, we observed evidence of anti-immunity, where mice were challenged by the virus and there was no sign of infection.
" to develop the vaccine, the authors inserted the SARS-CoV-2 prickly protein (S protein) gene into another virus called adenovirus, which uses S protein to invade cells and causes the common cold.
, however, they adjusted the adenovirus so that it could not cause disease.
harmless adenovirus brings S protein into the nasal cavity, allowing the body to protect against SARS-CoV-2 virus without getting sick.
in addition to nasal delivery, the new vaccine introduces two mutations in the S protein, stabilizing it in a specific shape that is most conducive to the formation of antibodies against it. "Adenoviruses are the basis for many research vaccines for COVID-19 and other infectious diseases, such as Ebola virus and tuberculosis, and they have a good record of safety and ability, but not much research has been conducted on delivering these vaccines through the nasal cavity," said Co-author of the
paper and professor of radiation oncology at the University of Washington's St. Louis School of Medicine.
all other adenovirus vaccines being developed against COVID-19 are given by injection into the arm or thigh muscles.
nose is a new way, so our results are surprising and promising.
important to produce such a strong immune response from a single dose of vaccine.
two doses to get a fully protected vaccine is less effective because some people have never received a second dose for a variety of reasons.
" Although a flu vaccine called FluMist is delivered through the nose, it uses a detoxifying form of the live flu virus and cannot be given to certain groups of people, including those with compromised immune systems due to diseases such as cancer, HIV and diabetes.
, the new COVID-19 in-nasal vaccine in the study did not use a replicable live virus, which is supposed to be safer.
the authors compared two ways in which the vaccine was delivered to mice -- nasal delivery and intramuscular injections.
intramuscular injections can induce an immune response to prevent pneumonia, but they do not prevent infections in the nose and lungs.
vaccine may reduce the severity of COVID-19, but it does not completely prevent infection or prevent infection from spreading the coronavirus.
by contrast, nasal dosing prevents infections in the upper and lower respiratory tracts ---nots and lungs--- suggesting that vaccinators do not transmit the virus or develop infections in other parts of the body.
the authors say the study is promising, but cautions that so far the vaccine has only been studied in mice.
Will soon begin a study to test the nasal vaccine in non-human primates, and plan to enter human clinical trials as soon as possible," Diamond said.
we are optimistic, but this needs to continue through the proper evaluation pipeline.
in these mouse models, the vaccine is highly protective.
We look forward to starting the next round of research and eventually testing it in people to see if we can induce protective immunity, which we believe not only prevents infection, but also curbs the spread of the virus."
"(Bioon.com) Reference: 1. Ahmed O. Hassan et al. A single-dose intranasal ChAd vaccine protects upper and lower respiratory tracts against SARS-CoV-2. Cell, 2020, doi:10.1016/j.cell.2020.08.026.2.Nasal vaccine against COVID-19 prevents in mice.