The H1N1 virus - widely known as swine flu - is the main strain being contracted, according to Public Health England (PHE).
Swine flu was responsible for the 2009-2010 pandemic, but is now considered to be "normal seasonal flu", as the number of people with some degree of immunity to it has increased.
The South of England has seen the highest number of cases of flu since October - with 113 cases reported, compared to 79 in the Midlands and the East of England, 39 in the North and just 22 in London.
PHE wrote to local authorities in the South West, stating they had received an "increased number of calls from schools reporting outbreaks of respiratory/flu-like illness" and offering advice for parents about how good hygiene practices can help protect children from the virus.
Dr Richard Pebody, head of flu surveillance at Public Health England told The Huffington Post UK:
“Our figures indicate flu continues to circulate in the community, with increases seen for several indicators in particular influenza confirmed hospitalisations amongst younger adults.
“Virus surveillance from the UK and elsewhere in Europe shows the strain A(H1N1)pdm09 [swine flu] is now the main seasonal flu virus and is currently well-matched to the vaccine strain at this stage. We will continue to closely monitor the epidemiological and virological situation as the flu season continues.
“Previous flu seasons dominated by A(H1N1)pdm09 suggest this strain particularly affects children, pregnant women, and adults with long term conditions like chronic heart disease, liver disease, neurological disease and respiratory disease in particular.”
To help prevent flu the NHS advises:
- Regularly washing hands with soap and warm water.
- Regularly cleaning surfaces such as computer keyboards, telephones and door handles to get rid of germs.
- Teaching your child to use tissues to cover their mouth and nose when they cough or sneeze, and to put used tissues in a bin as soon as possible.
- Staying off school until they're feeling better and are free of symptoms - which is usually after a week.
E-bug offer free games to teach kids about the importance of hand washing.