The number of H1N1 swine flu cases doubled in England in the last week and the number of people to have died after contracting the virus was up again, Reuters quoted health officials as saying today. The Health Protection Agency said there were 53,000 new cases of the flu in England, up from 27,000 on the previous week. It said those aged between one and 14 have been the most affected. Health officials said the rise was not unexpected. "What is unexpected is we"re getting higher numbers of people in hospital intensive care units, 99 people last week in intensive care, that"s the highest figure since all of this began," said Liam Donaldson, England"s chief medical officer. "It does seem to be having quite a severe impact on a proportion of people which is causing us great concern," he told Sky News. The HPA said that so far there had been 93 deaths in England related to swine flu, with 10 in the last week. Scottish officials said on Thursday there had been four more deaths related to the virus in Scotland, including a teenage boy with underlying health problems, taking the total number to 21. Donaldson said the projected worst case scenario for the total number of deaths connected to the flu was now about 1,000. "A thousand people dying who are generally younger people not the elderly who die in the flu season, that is very, very unusual and striking. So we are not being complacent about this at all," he said, saying the NHS would come under great pressure. The latest flu figures come the day after the start of a nationwide vaccination programme. Frontline healthcare staff are to be the first to be vaccinated to prevent them catching the virus or spreading it to patients. The government has also designated a number of at risk groups who will be included in the first wave of the programme when it is extended across GP surgeries. These will include those aged over six months who fall into current seasonal flu risk groups and all pregnant women. In total, about 11 million people are in line for the first phase of vaccination with most people only needing one dose.