Vaccination against swine flu has started in the US and will soon begin in Europe, but many of those who should be first in line are having second thoughts.

Healthcare workers are a top priority for vaccination because they can infect vulnerable people and because their services are vital in a pandemic. Yet in a survey of UK nurses last week, 47 per cent said they would not get vaccinated.

Meanwhile, British hospital bosses quizzed by The Guardian newspaper claim that as few as 10 per cent of staff will have the shot. In the US, many hospital employees are protesting against rules saying they must be vaccinated or lose their jobs.

Children are also at the top of the vaccine list. In the US summer outbreak, the age group most hospitalised was children under 4. Yet 40 per cent of US parents say they won’t vaccinate their kids, according to a poll by the University of Michigan.

Many parents and health workers argue that swine flu is not dangerous enough to justify the potential side effects of a vaccine, but this week there were fresh warnings that the virus can cause serious illness. In Canada and Mexico respectively, 17 per cent and 41 per cent of people admitted to intensive care with the virus have died. In Mexico, half had no underlying health problems; in Canada 70 per cent had no major illness beforehand.