COVID-19 Vaccine Trial in UK, China Shows Promise

Monday, 20 July 2020 (HealthDay News)-Highly Expected Results of Two Early Stage Clinical Trials of COVID-19 Vaccine Candidates Suggest They Are Safe and May Protect Recipients However, the duration of the effect is still unknown.

“We’re moving into an era of rapidly emerging vaccines against the new coronavirus,” said Dr. Ameshuadalya, an infectious disease expert and senior researcher at the Johns Hopkins Health Security Center in Baltimore. States.

Adalja was not involved in the new trial, but called it “inspiring and important because it shows Phase 1 and 2 data for a larger patient group.”

The largest and longest of the two trials was conducted among 1,077 British adults aged 35 on average, with no known exposure to the new coronavirus, SARS-CoV-2. ..

As reported on July 20 LancetThe team, led by Andrew Pollard of Oxford University, said the vaccine effectively stimulates two arms of the immune system against the virus.

“There are two ways the immune system can detect and attack pathogens-antibody and T cell responses,” Pollard explained in a journal news release. “This vaccine is meant to provoke both, so it can attack the virus as it circulates in the body or attack infected cells.”

People in this Phase 1/2 trial were either on an or “control group” vaccine (a meningitis vaccine in this case) given to a UK hospital between April 23 and May 21. Received 8 weeks of trial.

According to Pollard’s group, blood samples taken from the recipients found strong immune system antibody responses and strong T cell responses in those vaccinated with coronavirus vaccines.

This is important because researchers are key to a successful vaccine, activating both of these responses to recognize, target, and destroy SARS-CoV-2 infected cells.

The ideal vaccine would provide such protection for at least 6 months, but is currently only in study week 8. Nonetheless, the T-cell response peaked 14 days after vaccination and was only slightly reduced by day 56, the researchers said.

The antibody response peaked by 28 days and was still high by 56 days, the group added.

Giving people a second “booster” shot of the vaccine seemed to boost the antibody response, but did not affect the T cell response.

Regarding side effects, Pollard’s team said they had no serious effects on hundreds of vaccinated people, but temporary mild/moderate effects were common-symptoms such as fatigue and fever. Was commonly relieved by the use of analgesics (such as acetaminophen).

Despite this early commitment, study co-author Sarah Gilbert of Oxford University emphasized that the trial was too short to say anything about long-term efficacy. The scope of research should also be expanded to include the elderly and people with underlying illnesses.

“There are many things we still have to do before we can see if the vaccine will help manage the COVID-19 pandemic, but these early results are promising,” Gilbert said. “In addition to continuing to test vaccines in Phase 3 trials, we need to learn more about viruses. For example, how strong are the immune responses that need to be elicited to effectively protect against SARS-CoV-2? I don’t know yet. Infection.”

To create the Oxford vaccine, researchers used a weakly genetically engineered version of the adenovirus, which is a common chimpanzee-sensing adenovirus, the type of virus behind the common cold. The fine-tuning of the gene involved altering the adenovirus so that the surface contained “spike protein” structures that mimic those found in SARS-CoV-2.

“This means that when the adenovirus enters cells of vaccinated people, it also delivers the genetic code for the spike protein,” Pollard explained. “This causes the cells of these people to make spike proteins and teach the immune system to recognize the SARS-CoV-2 virus.”

Chinese researchers have also used a similar approach to help produce a second candidate vaccine, with test results reported as follows: Lancet..

In a Phase 2 trial, a team led by Feng-Cai Zhu of the Jiangsu Center for Disease Control and Prevention administered 382 high- or low-dose candidate vaccines and another 126 received’dummy’ placebo shots. It was. ..

Two-thirds of participants were 18-44 years old, a quarter were 45-54 years old, and the remaining 13% were 55 years old or older.

By 28 days after vaccination, 95% of people who received high doses and 91% of people who received low doses had either a T cell or antibody immune system reaction, Chu’s group said. ..

“Side effects” to the vaccine-symptoms such as fever, fatigue, and discomfort at the injection site-are common, with about three-quarters of recipients reporting such symptoms. However, the researchers classified most of these reactions as mild or moderate.

As with the British case, questions about the duration of protection remain. No one was intentionally exposed to SARS-CoV-2 as part of the trial, so it’s still unclear how effective the shot would be in real-world situations.

Both teams said the research was going on. The Oxford team said the UK-based Phase 2 trial is already underway, and more advanced Phase 3 trials are underway (running in the UK, Brazil and South Africa).

A long-term effective vaccine is the world’s greatest hope for the early termination of the COVID-19 pandemic. Over 250 candidate vaccines are currently under investigation worldwide and billions of dollars have been devoted to this study.

For more information

The Centers for Disease Control and Prevention New coronavirus..