The NHS is facing "exceptional" levels of demand over swine flu
There are indications the number of swine flu cases in England is no longer rising rapidly and may have "plateaued", officials have said.
There were an estimated 110,000 new cases of swine flu last week, compared with 100,000 the week before.
There is also a big drop in five to 14-year-olds consulting GPs, coinciding with the start of the school holidays.
Meanwhile, officials say more than half of children taking Tamiflu suffer side-effects such as nausea and insomnia.
England's swine flu helpline - a telephone and web-based helpline service designed to relieve pressures on the NHS and GPs - launched last week.
Those with symptoms including a fever or temperature over 38C or 100.4F - coupled with unusual tiredness, headache, runny nose, sore throat, shortness of breath or cough, loss of appetite, aching muscles, diarrhoea or vomiting - are eligible for anti-viral drugs.
In the first seven days of the service, 150,000 people were given tamiflu.
England's Chief Medical Officer, Sir Liam Donaldson said he believed that many of these cases were in people who would not have gone to the GP and previously would have been undiagnosed.
But he added there were also indications the service was taking pressure off out of hours services and NHS Direct.
"I think we are probably seeing a downturn in the illness at the moment but we don't anticipate it staying away," he said.
"We expect to see a big surge in autumn."
GP consultations had previously been doubling week on week.
Figures suggest that some different areas are now being affected, with higher rates than previously in some areas of the North West and South West.
Overall, around one in every 150 people in England has had swine flu so far and there have been 27 deaths.
This figure is higher in younger age groups with one in 90 under ones and one in 77 one to four year olds infected since the start of the pandemic.
Meanwhile, officials have also said two studies from experts at the Health Protection Agency (HPA) showed a "high proportion" of British schoolchildren reporting problems after taking Tamiflu.
The data was gathered from children at three schools in London and one in south-west England who were given Tamiflu earlier this year after classmates became infected.
The researchers concluded that a "high proportion of school children may experience side-effects of oseltamivir (Tamiflu) medication".
Call for clarity
Earlier this week, a report from the Lords' science and technology committee criticised the government's handling of swine flu saying some of its pandemic plans were under-prepared.
It said the national swine flu helpline in England should also have been set up sooner and asked for assurances that it will cope with high demand this autumn.
And it called for for clarity on how intensive and critical care departments will cope with high patient numbers.
Intensive care specialists had already warned that swine flu cases could overwhelm intensive care departments in England.
Ian Dalton, the National Director for NHS Flu Resilience, said he was working with the 10 Strategic Health Authorities to produce an updated critical care plan by the end of August.
"It will set out the action that has to be taken in order to increase critical care capacity.
"I would like to reassure people that this will build on a lot of previous planning," he said.
There has been a slight rise in swine flu cases in Scotland, with 4,300 cases in the past week.
Wales is also reporting a small rise in cases of flu-like illness with 4,410 in the past week and Northern Ireland saw 10 new cases.
The flu service is not covering the rest of the UK, as Wales, Northern Ireland and Scotland have all experienced much less demand.
The flu hotline number is 0800 1 513 100