SWINE flu could be back with a vengeance later this year, health chiefs have warned.

Bosses at NHS Bolton are renewing their calls for anyone eligible to be vaccinated against the virus to come forward.

It comes as figures reveal more than 20,000 “priority cases” out of a possible 80,000 had the jab in November and December.

Up to date statistics and the number of children vaccinated are expected in the next few weeks.

The number of cases has fallen to the same level as at the early stages of the outbreak, fewer than 5,000 across the country in the last week, and the closure of the National Pandemic Flu Service, from February 11, has been announced.

However, health chiefs have stressed that a threat remains.

Jan Hutchinson, director of public health at NHS Bolton, the primary care trust which oversees health services, said: “I’m really pleased with the progress we have made so far in getting people vaccinated who are particularly at risk from the H1N1 virus.

“This is thanks to the hard work and co-operation of GPs, practice nurses, PCT staff and others. It has been a great team effort which is continuing.”

But she added: “This virus is likely to be around for some time, and can have serious complications for some people, so it’s certainly still worthwhile getting immunised if you are in an at risk group.”

It comes after the chief medical officer for England, Sir Liam Donaldson, stressed the importance of being vaccinated, predicting swine flu will continue to be a threat for many years.

The priority groups for the vaccination include people with underlying health conditions, pregnant women and those aged 65 and over who are eligible for the seasonal flu vaccine.

Since December children aged between six-months and five-years-old have also been eligible for immunisation, as they are among the most likely to be seriously ill and require hospital treatment if they were to catch the virus.

Anyone who is eligible for the vaccine should contact their GP for more information.

cherry.thomas@thebolton news.co.uk