UK coronavirus vaccine prompts immune response in early test

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 first began testing the vaccine in April in about 1,000 people, half of whom got the experimental vaccine. Such early trials are usually designed only to evaluate safety, but in this case experts were also looking to see what kind of immune response was provoked.

In research published Monday in the journal Lancet, scientists say that they found their experimental COVID-19 vaccine produced a dual immune response in people aged 18 to 55.

“We are seeing good immune response in almost everybody,” says 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,” he says.

Hill says that neutralizing antibodies are produced — molecules which are key to blocking infection. In addition, the vaccine also causes a reaction in the body’s T-cells which help to fight off the coronavirus.

He says that larger trials evaluating the vaccine’s effectiveness, involving about 10,000 people in the UK as well as participants in South Africa and Brazil are still underway. Another big trial is slated to start in the US soon, aiming to enroll 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 estimates they might have sufficient data by the end of the year to decide if the vaccine should be adopted for mass vaccination campaigns.

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

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

— AP