Wave of Study Promising Results Raises Hope for Coronavirus Vaccines

CHICAGO (Reuters) – Early data from trials of three potential COVID-19 vaccines released Monday, including a closely watched Oxford University candidate, raised confidence that a vaccine can train the immune system to recognize and combat the new coronavirus without serious side effects

It is still unclear whether any of these efforts will result in a vaccine capable of protecting billions of people and ending the global pandemic that has claimed more than 600,000 lives. They will all require much larger studies to show that they can safely prevent serious infections or illnesses.

The vaccine developed by the British pharmacist AstraZeneca (AZN.L), in conjunction with the University of Oxford, induced an immune response in all study participants who received two doses without any worrisome side effects.

A coronavirus vaccine in development by CanSinoBiologics Inc (6185.HK) and China’s military research unit also showed that it appears to be safe and induced an immune response in most of the 508 healthy volunteers who received one dose of the vaccine, the researchers reported.

About 77% of the study volunteers experienced side effects such as fever or pain at the injection site, but none considered it serious.

Both the AstraZeneca and CanSino vaccines use a harmless cold virus known as adenovirus to transport genetic material from the new coronavirus to the body. Studies on both vaccines were published in The Lancet.

“Overall, the results of both trials are very similar and promising,” wrote in a comment in The Lancet Naor Bar-Zeev and William Moss, two vaccine experts at the Johns Hopkins Bloomberg School of Public Health.

However, candidate CanSino again showed signs that people who had previously been exposed to the particular adenovirus in their vaccine had a reduced immune response.

The study authors called it “the biggest hurdle” for the vaccine to overcome.

German biotechnology BioNTech (22UAy.F) and the American pharmacist Pfizer Inc (PFE.N) published details of a small study in Germany of a different type of vaccine that uses ribonucleic acid (RNA), a chemical messenger that contains instructions for making proteins.

The vaccine instructs cells to make proteins that mimic the outer surface of the coronavirus. The body recognizes these virus-like proteins as foreign invaders and can then mount an immune response against the actual virus.

In the yet-unpaired peer-reviewed study of 60 healthy adults, the vaccine induced virus-neutralizing antibodies in those who received two doses, a result in line with a previous early-stage trial in the United States. The ad explosion followed the release of Moderna Inc’s results last week (MRNA.O) vaccine trial, showing equally promising early results. Moderna’s vaccine also uses a messenger RNA platform.

“It is encouraging that all of these vaccines appear to induce antibodies in people,” said former assistant director general of the World Health Organization (WHO), Marie-Paule Kieny of the French research institute Inserm. “This shows that science is advancing very quickly, which is a good sign.”

‘A LONG WAY TO GO’

None of these top contenders have shown any side effects that could marginalize their efforts thus far, but all must demonstrate that they are safe and effective in trials involving thousands of subjects, including those at high risk for severe COVID-19, such as the elderly. . and people with diabetes.

Historically, only 6% of vaccine candidates end up coming to market, often after a long-standing testing process. Vaccine manufacturers hope to dramatically compress that timeline through faster testing and manufacturing at scale even before products succeed.

Several manufacturers are backed by the US government with the goal of having a coronavirus vaccine by the end of the year as cases continue to rise at a record rate.

The Oxford / AstraZeneca vaccine is one of 150 in development worldwide, but is considered the most advanced. Late-stage trials have started in Brazil and South Africa, and should start in the United States, where the prevalence of infection is highest.

In its Phase I trial, the vaccine induced so-called neutralizing antibodies, the type that prevents the virus from infecting cells, in 91% of people one month after receiving a dose, and in 100% of subjects who they received a second dose. These levels were on par with the antibodies produced by the people who survived COVID-19, a key benchmark of potential success.

Oxford researcher Sarah Gilbert said the trial was unable to determine whether one or two doses would be needed to provide immunity.

The vaccine, known as AZD1222, also induced the body to produce T cells, activating a second part of the immune system that experts increasingly believe will be important for a lasting immune response.

Recent studies show that some recovered patients who tested negative for coronavirus antibodies developed T cells in response to their infection. Scientists think that both are important aspects of an effective coronavirus vaccine.

Dr. Mike Ryan, head of the WHO emergency program, said the generation of both T-cell and neutralizing antibody responses was positive, adding that “there is a long way to go.”

Open here in an external browser for a Reuters chart of vaccines and treatments in development.