New experimental study effective against pneumonia in SARS-CoV-2 infected mice: Study

A new experimental research proved to be effective against pneumonia in SARS-CoV-2 infected mice, as per the study carried by the researchers at the Washington University School of Medicine in St. Louis which was published in the News Medical Life Sciences journal.

The vaccine, made from a mild virus genetically modified to carry a key gene from the Covid-19 virus, is described in the journal Cell Host and Microbe.

“Unlike many of the other vaccines under development, this vaccine is made from a virus that is capable of spreading in a limited fashion inside the human body, which means it is likely to generate a strong immune response,” said co-senior author Michael S Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine and a professor of molecular microbiology, and of pathology and immunology.

Diamond mentioned that since the virus is capable of replicating, it can be grown to high levels in the lab, so it’s easy to scale up and should be more cost-effective than some of the other vaccine candidates.

He added: “So while what we have shown is just proof of concept, I think it’s very promising. Our vaccine candidate is now being tested in additional animal models with the goal of getting it into clinical trials as soon as possible.”

The researchers created the experimental vaccine by genetically modifying vesicular stomatitis virus (VSV), a virus of livestock that causes only a mild, short-lived illness in people.

Swapping, subgrouping

They swapped out one gene from VSV for the gene for a spike from SARS-CoV-2, the virus that causes Covid-19. The hybrid virus is called VSV-SARS-CoV-2.

The researchers then induced VSV-SARS-CoV-2 in mice. A subgroup was boosted with a second dose of the experimental vaccine four weeks after the initial injections.

Three weeks after each injection, the researchers drew blood from the mice to test for antibodies capable of preventing SARS-CoV-2 from infecting cells.

They found high levels of such neutralising antibodies after one dose, and the levels increased 90-fold after a second dose.

In their last dose, researchers induced the SARS-CoV-2 virus into their noses. Four days post-vaccination, no infectious virus detectable in the lungs of mice that had been given either one or two doses of the vaccine. The vaccine completely eradicated pneumonia.

In contrast, mice that had received the placebo had high levels of virus in their lungs. In addition, the lungs of vaccinated mice showed fewer signs of inflammation and damage than those of mice that had received the placebo. The experimental vaccine is still in the early stages of development, News Medical Life Sciences published in its journal.