UK virus vaccine encouraging

It prompts immune response in tests; bigger trials underway

LONDON — Scientists at Oxford University say their experimental coronavirus vaccine has been shown in an early trial to prompt a protective immune response in hundreds of people who got the shot.

British researchers began testing the vaccine in April in about 1,000 people, half of whom got the experimental vaccine. Such early trials are designed to evaluate safety and see what kind of immune response was provoked, but can’t tell if the vaccine truly protects.

In research published Monday in the journal Lancet, scientists said that they found their experimental COVID-19 vaccine produced a dual immune response in people aged 18 to 55 that lasted at least two months after they were immunized.

“We are seeing good immune response in almost everybody,” said Dr. Adrian Hill, director of the Jenner

Institute at Oxford University. “What this vaccine does particularly well is trigger both arms of the immune system.”

Hill said that neutralizing antibodies are produced — molecules that are key to blocking infection. In addition, the vaccine causes a reaction in the body’s T-cells, which help by destroying cells that have been taken over by the virus.

The experimental COVID-19 vaccine caused minor side effects like fever, chills and muscle pain more often than in those who got a control meningitis vaccine.

Hill said that larger trials evaluating the vaccine’s effectiveness, involving about 10,000 people in the U.K. as well as participants in South Africa and Brazil are still underway. Another trial is slated to start in the U.S. soon, aimed at enrolling about 30,000 people.

How quickly scientists are able to determine the vaccine’s effectiveness will depend largely on how much more transmission there is, but Hill estimated that if there was enough data to prove the vaccine’s efficacy, immunization of some high-risk groups in Britain could begin in December.

He said the vaccine seemed to produce a comparable level of antibodies to those produced by people who recovered from a COVID-19 infection and hoped that the T-cell response would provide even more protection.

“There’s increasing evidence that having a T-cell response as well as antibodies could be very important in controlling COVID-19,” Hill said. He suggested the immune response might be boosted after a second dose; in a small number of people, their trial tested two doses administered about four weeks apart.

Hill said Oxford has partnered with drugmaker Astrazeneca to produce its vaccine globally, and the company has committed to making 2 billion doses.