Boris Johnson said on Monday there were some hopeful signs that a vaccine would be secured for COVID-19, but he warned that the country must be realistic because it could not be taken for granted."There are some very hopeful signs not least from the Oxford AstraZeneca trials that are being conducted but as (the lawmaker asking the question) knows SARS took place 18 years ago, we still don't have a vaccine for SARS," he told parliament, reported Reuters."I don't wish to depress him but we must be realistic about this, there is a good chance of a vaccine but it cannot be taken for granted," the UK PM said.Moreover, Johnson imposed a three-tiered system of further restrictions on parts of England including shutting pubs as the COVID-19.