3 COVID-19 vaccine goes further to final stage of testing

The Oxford candidate vaccine elicited an antibody immune response within 28 days post vaccination and a T cell immune response within 14 days post vaccination.

These were still present 56 days after vaccination. Researchers will continue to monitor participants for at least a year to see how long the immune response lasts.

Neutralizing antibodies (the levels that can neutralize the virus) were detected in most people after one dose of vaccine and in all those who received a second boost 28 days after the first dose. It was.

Only 10 received the second dose.

Neutralizing antibodies have been found in the plasma of people who have recovered from COVID-19, but scientists still do not know what level of antibody protects people from the new coronavirus.

However, Fuller says induction of both types of immune responses specific for the new coronavirus is a good sign.

“There is growing evidence to suggest that T cell responses may play an important role in protection from SARS-CoV-2,” she said.

Antibodies stimulate the immune system to target viruses and other invaders of the blood and lymph system. T cells are part of the cellular immune response and help the immune system attack infecting cells.

“T cells are like a backup plan,” says Fuller. “If there aren’t enough antibodies to stop the infection, T cells can invade and find infected cells and quickly eliminate them.”

The vaccine trial included 1,077 healthy adults aged 18-55 from the United Kingdom. None of them had a history of SARS-CoV-2 infection. About half were women and over 90% were white.

Given the limited range of people included in the study, it is not clear how well the vaccine will work in the elderly, in other health groups, or in ethnically and geographically diverse populations.

Mild or moderate side effects were fairly common among the vaccinated people, with fatigue or headache being the most frequent. Other common side effects include injection site pain, muscle aches, chills, and high temperatures.

Certain side effects were reduced in those who took the painkillers before and 24 hours after vaccination. Side effects after the second dose of the vaccine were less common.

Researchers have already begun Phase 3 trials of candidate vaccines in Brazil, South Africa and the United Kingdom.

AstraZeneca says it has the ability to produce 2 billion doses of vaccine if found to be effective in later clinical trials. CNN Report..

There are 24 COVID-19 candidate vaccines in clinical trials around the world, and another 141 are in the early stages of development, According to the World Health Organization..

Phase II trials of CanSino candidate vaccines have been shown to be generally safe and induce an immune response.

The vaccine trial conducted in Wuhan, China, involved 508 healthy adults up to 83 years of age. I didn’t have a COVID-19 before.

The researchers randomly assigned people to receive either high or low doses of the candidate vaccine or inactive placebo.

Fewer people developed neutralizing antibodies than the Oxford study, with 59% in the high-dose group and 47% in the low-dose group.

However, the candidate vaccine elicited a T cell response in 90% of the high dose and 88% of the low dose groups.

Both types of immune reactions were present on day 28.

This vaccine uses the attenuated human cold virus (adenovirus) to send the genetic code for a new coronavirus spike protein to the body’s cells.

The cell then produces a spike protein that teaches the immune system to recognize the protein and fight the new coronavirus.

Fuller says that many people around the world are already exposed to the common cold virus and therefore have some degree of immune protection. This can interfere with the immune response generated by vaccines that use adenovirus as the delivery system.

Chinese researchers have seen this kind of sluggish immune response in people who had existing immunity to adenovirus.

The Oxford vaccine also uses adenovirus to provide the new coronavirus genetic code, but it’s a chimpanzee adenovirus, so you don’t have to worry so much, Fuller says.

“We haven’t been exposed to the adenovirus yet,” she said, “so it could trigger a full immune response.”

Antibody responses from the CanSino candidate vaccine were also lower in people over the age of 55. This age group is currently Higher risk of severe COVID-19.. Age did not affect T cell responses.

Most side effects of this candidate vaccine were mild or moderate. However, 9% of people in the high-dose group showed the most common serious side effects of fever.

In the accompanying commentary Posted in Lancet, Naor Bar-Zeev, PhD,and Dr. William J. Moss Members of the Johns Hopkins Bloomberg School of Public Health write that the trials are “widely similar and promising,” and the safety data are “safe.”

But “a lot remains unclear about these and other COVID-19 vaccines in development,” they added. [immune responses] In certain other groups, such as the elderly, people with comorbidities that are often excluded from clinical trials, and races or groups of races with more severe COVID-19 effects. “

Some of these answers come from Phase 3 clinical trials. In these large studies, researchers follow vaccinated people to find out if they are exposed to the new coronavirus or if they have COVID-19.

However, these studies should include a more diverse group of volunteers.

“This needs to be done in the next set of studies, to really consider whether they can be vaccinated. [other] Fuller of the Oxford vaccine said. “Or will this be a vaccine limited to healthy young people?”