What to do if you catch the virus
Unless you are elderly, pregnant or suffer from a chronic illness, the HSE advises flu sufferers to stay away from GP surgeries and A&E departments as most symptoms can be treated at home.
Symptoms like a sore throat, fever and muscle ache and a feeling of being very unwell will develop in the first 24 to 48 hours and come on more suddenly than typical cold symptoms.
To counter this, drink plenty of fluids to replace those lost from sweating.
Get lots of rest and eat healthily.
People at high risk of complications should get specific anti-viral medicine from their GPs and take it within the first 48 hours.
After three to five days, symptoms will peak and you will feel at your worst. Continue to drink plenty of fluids and get lots of rest and continue to eat well.
After five to eight days, symptoms should have abated but a persistent cough and general tiredness may last for another two to three weeks.
Continue to drink lots of fluids, eat healthily and return to normal activities only when you feel better.
High risk sufferers, however, are urged to get a flu jab if they have not done so already.
According to the HSE, the predominant flu strain AH3 is affecting mostly older people rather than younger age groups.
Those who have not already contracted the strain are strongly advised to get a flu jab from their GPs or pharmacists, where the service is free for medical card holders.