US vaccine ‘safe and generates antibodies’
The first coronavirus vaccine tested on humans appears safe and generated antibodies that stopped the virus replicating, according to early trial results.
Eight healthy volunteers saw few adverse effects after taking two doses of the potential vaccine, Moderna, its US manufacturer, said yesterday.
It appeared to trigger an immune response – the critical requirement of a working vaccine – producing ‘‘neutralising antibodies’’ in all eight patients. The levels of antibodies were similar to those found in patients who had caught Covid-19 and then recovered.
Dr Tal Zaks, the Moderna chief medical officer, called the result a ‘‘first important step’’, with much more testing needed, while some medical experts urged caution, seeking more data.
A second phase of trials with around 600 people will begin soon, with a third involving thousands of people set to start in July. Moderna’s stock price soared 40 per cent in premarket trading as the results emerged.
However, the positive news is only one step on the long road to a potential vaccine.
Even if the trials are successful Moderna’s vaccine would not be available until between January and June 2021.
After some doubt that a vaccine could be found, the results provide hope of a breakthrough.
Three different doses of the potential vaccine were trialled, with the positive results found in those who tried the low and medium doses. Only one participant who took these doses had any adverse reaction, a redness around the point of injection on the arm that eventually cleared.
The high dose – which is expected to be eliminated from future trials – saw more adverse reactions, including fever and headaches.
Moderna said that when the vaccine – called mRNA-1273 – was given to mice who were then exposed to coronavirus, the virus did not multiply in the lungs.
Stephane Bancel, the Moderna chief executive, told The Washington Post: ‘‘We are very, very happy because first the vaccine was generally safe. The piece that was really exciting and was the big question, of course, was can you find antibodies in people in enough quantities [to prevent disease]?’’
Peter Jay Hotez, who is developing a vaccine at the Baylor College of Medicine, Texas, told the paper it would be important to see the exact level of antibodies produced in each participant. US stock markets surged in early trading as news of the results emerged, with the Dow Jones industrial average initially up 3.5 per cent.
The promising US news came as scientists warned that the University of Oxford vaccine tipped as a ‘‘front-runner’’ in the race may only be partially effective. A trial of the vaccine in rhesus macaque monkeys did not stop the animals from catching the virus and has raised questions about the vaccine’s likely human efficacy and ongoing development.