Government advisers are preparing for the mass vaccination of schoolchildren to stop the spread of swine flu.

A committee of scientists advising the Department of Health is expected to recommend that the vaccination of 10 to 18-year-olds begins by the end of the year.

The plans come amid growing concern about the number and severity of infections in children. Figures released last week show that children under the age of 15 account for a fifth of all swine flu hospital admissions. A total of 217 children have been treated in hospital, including 27 who are in critical care.

Overall, the number of new cases in England increased by 50% last week to 78,000.

The government’s vaccination programme, which began last month, is targeting 11m priority patients and frontline health workers. The patients include pregnant women and those with conditions such as asthma and diabetes.

Last month the joint committee on vaccination and immunisation discussed extending the programme to include under-18s, once the priority cases have been vaccinated. If the virus continues to spread at current rates and enough vaccine is available, it will be extended to schoolchildren.

Professor Peter Openshaw, an expert on respiratory infections at Imperial College London and a member of the committee, said: “As increasing quantities of vaccine become available, then the initial recommendations will be extended [to children and teenagers].

“It depends on the emerging circumstances such as the efficacy and availability of the vaccine and the spread of the virus.”

Scientists believe the virus is more severe in children because they have not been exposed to related outbreaks. The elderly, by contrast, have not suffered as badly.

The United States is already offering immunisation to everyone aged from six months to 24 years, in addition to at-risk groups.

In Britain, vaccination is likely to focus initially on children aged 10 to 18. The committee is waiting for further research to be completed about the effectiveness of the vaccine in younger children.

The move to vaccinate children was backed by the Royal College of General Practitioners.

Steve Field, its chairman, said: “If there is enough vaccine available, it would be sensible to use it for children, who are the most vulnerable. They have had no previous immunisation or exposure to the virus.”

A spokesman for the Department of Health said: “The vaccination programme is in its early stages, allowing time to plan for which groups will be offered the vaccine next. A decision has not yet been made.”