UK’s coronavirus vaccine is safe and induces an immune response
The vaccine provoked a T cell response within 14 days of vaccination, and an antibody response within 28 days.
The current trial is too preliminary to confirm whether the new vaccine meets full vaccine requirements, but phase 2 and phase 3 trials to confirm whether it effectively protects against coronavirus infection will now happen in the UK, Brazil and South Africa.
An ideal vaccine against coronavirus should be effective after one or two vaccinations, work in target populations including older adults and those with other health conditions, confer protection for a minimum of six months, and reduce onward transmission of the virus to contacts.
Professor Andrew Pollard, lead author of the study at University of Oxford, said: “The immune system has two ways of finding and attacking pathogens – antibody and T cell responses.
“This vaccine is intended to induce both, so it can attack the virus when it’s circulating in the body, as well as attacking infected cells. We hope this means the immune system will remember the virus, so that our vaccine will protect people for an extended period.
“However, we need more research before we can confirm the vaccine effectively protects against SARS-CoV-2 infection, and for how long any protection lasts.”
The new trial included 1,077 healthy adults aged 18-55 years with no history of COVID-19, and took place in five UK hospitals between 23 April and 21 May 2020.
The data included in the paper covered the first 56 days of the trial and is ongoing.
Meanwhile, a phase 2 trial of an Ad5 vectored COVID-19 vaccine candidate, conducted in China, has found that the vaccine is safe and also induces an immune response.
Both studies were published in The Lancet.
Commenting on the trials, Assistant Professor Naor Bar-Zeev, International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, USA, said: “These trial reports are hugely anticipated. The results of both studies augur well for phase 3 trials, where the vaccines must be tested on much larger populations of participants to assess their efficacy and safety… Both trials used adenovirus vectors to deliver and study the COVID-19 vaccine, an innovative and efficient means of vaccine development in the midst of a pandemic.
“Capable of generating humoral, cellular, and innate responses, adenovirus vectored vaccines have much potential.”
However, he warned of the preliminary nature of the two vaccine candidates.