Thousands of children across the country may have had swine flu without feeling ill, the Health Protection Agency (HPA) says.
Professor Maria Zambon, director of the HPA's centre for infections, said as many as a third of school-age youngsters had caught the virus, but fewer than one in 10 had displayed symptoms.
"When we actually put together all the different pieces of information it suggests that up to a third of children in particular regions of England were infected in the first wave," Professor Zambon explained.
"We have not got the pandemic we planned for, so we should really focus on all the positives.
"We have been able to make a vaccine and we have been able to roll out the vaccine in a concerted and efficient manner."
Professor John Watson, head of the HPA's respiratory diseases department, added that half or more of all people with H1N1 would not become sick.
The HPA said it was unclear what course the current flu pandemic would take or if there would be a second wave of cases.
"We have only just begun vaccinating the housebound and a lot of those eligible and on the waiting list since before Xmas are now being offered but declining. I think there has been media hype causing a real frenzy. Not to mention the huge amount of money the vaccine cost and the wastage now occurring" - Liz Matson, Devon
"No, we have started to give the vaccine last week, so it can not possibly be responsible for averting a pandemic, I believe it was media hype that caused a problem for people, is it true that at this point less people have died as a result of flu this year than in previous years" - Amanda Youle
"No. The vaccine is not available to many people but lack of testing and under reporting of incidence both in hospital and GP surgeries" - Doreen Dawson, Lancashire