Researchers at the University of Oxford believe they may have a breakthrough in their search for a COVID-19 vaccine after the team discovered that the jab could provide "double protection" against the deadly novel coronavirus following early stage of human trials, according to media reports in the UK. Blood samples taken from a group of UK volunteers given a dose of the vaccine showed that it stimulated the body to produce both antibodies and "killer T-cells", a senior source from the trial was quoted by 'The Daily Telegraph' as saying.

The discovery is promising because separate studies have suggested that antibodies may fade away within months while T-cells can stay in circulation for years. However, the source cautioned that the results, while "extremely promising", did not yet prove that the Oxford vaccine provides long-lasting immunity against the virus.