LONDON, Oct 28 (Reuters) - Britain has reported 39,842 new cases of COVID-19, government data showed on Thursday, meaning cases reported between Oct. 22 and Oct. 28 were down 9.8% compared with the previous seven days. A further 165 people were reported as having died within 28 days of a positive test for COVID-19, meaning the seven-day total was up 16.2% from the previous week. Changes in the number of deaths typically lag those for cases. A total of 49.84 million people had received a first dose of a vaccine against coronavirus by the end of Oct. 27 and 45.63 million people had received a second dose.