LONDON (Reuters) – British health officials on Wednesday warned that increased circulation of flu and a resurgence in COVID-19 could lead to a difficult winter that increases pressure on the already stretched National Health Service (NHS). Warnings over a possible “twindemic” of COVID-19 and flu have been issued each winter since the start of the coronavirus pandemic in early 2020, but COVID restrictions that limited social contact have meant flu levels stayed low. However, the government ended coronavirus restrictions earlier this year, meaning that social contact rates have returned to near …