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School playgrounds across Auckland have been emptier this week, as hundreds of children have been hit with a flu-like illness.
An outbreak of symptoms including high fever, vomiting and sore throats have been reported, with many schools advising parents to make sure sick children are fully recovered before they return them to school.
Campbells Bay School in North Shore _ which has a role of about 650 _ reported in its newsletter this week that more than 100 children were off sick on Monday.
A spokesperson said there had been an "uncommonly high" number of students unwell, but the absences had not affected showings of the school production Seussical Jr, which opened on Monday.
Royal Oak Primary has also had high student absences.
"There's been a lot of children away. Certainly in our school _ I saw a report on it this morning and that has been reflected at our school," acting principal Christopher Nixon said.
Avondale Primary School has seen a significant number of children away sick, with a few staff members also suffering sore throats.
West Harbour School in Waitakere had not been hit "epidemic-style", a spokesman said.
As a result of the outbreak, the Auckland Regional Health Service has issued a health alert, advising people to take extra note of personal hygiene and cleanliness.
Medical officer of health Dr Craig Thornley said many people get sick during the winter season and it was important to take extra care.
"People often say to cough into your hands, but that's where the bacteria goes and stays _ you might go and shake your hands with someone and then pass it on to them," he said.
"It's better to cough into the inside of your elbow if you don't have a tissue readily available and then you're not directly passing it on to others."
Dr Thornley said the levels of influenza reported in Auckland this year had been higher than last year's statistics _ but influenza and the "ordinary flu" were two different things.
"The message is the same though. You have to be careful and wash your hands using the 20/20 rule _ 20 seconds washing and 20 seconds drying," he said.
"I recommend that children who are sick stay at home so they don't spread it to other children."