Vaccine protects COVID-19 survivors against variants; virus' spike protein damages blood vessels

(Reuters) - The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

Vaccine protects COVID-19 survivors against variants

In COVID-19 survivors, the Pfizer/BioNTech, mRNA vaccine protects not only against the original virus strain but also against worrisome variants, two studies show. UK researchers analyzed immune responses after a single dose of the vaccine in 51 people, including 25 people previously infected with an early version of the novel coronavirus.

Survivors showed enhanced antibody responses against the newer, more infectious variants first seen in the UK and South Africa, whereas people who had not previously been infected did not produce antibodies that could neutralize the variants, according to a report on Friday in Science. Separately, U.S researchers studied 30 people after two doses of the vaccine.

Immune responses were 3.4 times better at neutralizing the coronavirus in the 10 COVID-19 survivors than in the 20 who were not previously infected, they reported on medRxiv on Thursday ahead of peer review. The difference was even greater when looking at neutralization of new variants from the UK, South Africa and Brazil, said coauthor Fikadu Tafesse of Oregon Health & Science University.

"For example, the South African variant, which is the best at evading neutralizing antibodies, was 6.5 times better blocked," or neutralized, in blood samples from people who were vaccinated after infection, he said. "Our findings give people another reason to go out and get vaccinated even if they have already had COVID-19."

COVID-19 spike protein damages blood vessels

The "spike" proteins that the coronavirus uses to help it break into cells inflicts other damage as well, according to a new study that shines a spotlight on the many ways COVID-19 attacks organs other than the lungs.

The spike proteins themselves cause direct damage to the cells that line the blood vessels, scientists found in test tube experiments using an engineered version of the spike and artery-lining cells obtained from mice.

After attaching itself to the ACE2 protein on healthy cells, the spike disrupts signaling from ACE2 to the mitochondria - the cell’s energy-generating structures - causing the mitochondria to become damaged, researchers reported on Friday in Circulation Research. COVID-19 is really a disease of the blood vessels, coauthor Uri Manor of the Salk Institute for Biological Studies in La Jolla, California said in a statement.

The new findings could help explain the blood clots associated with COVID-19. They could also explain "why some people have strokes, and why some people have issues in other parts of the body," Manor said. "The commonality between them is that they all have vascular underpinnings."