The number of flu cases in Northern Ireland has increased, the Public Health Agency (PHA) has warned.
The number of people consulting their GPs with the illness rose to 26 people per 100,000 during the sixth week of this year.
A PHA spokesman said: "Laboratories are now detecting more flu which also suggests that flu viruses are starting to circulate."
The strains identified are covered by this year's jab and the PHA warned at risk groups including newly-pregnant women to seek vaccination.
Dr Richard Smithson, consultant in health protection at the PHA, said: "We have seen a small rise in the number of seasonal flu cases. Receiving the seasonal flu vaccine is the best way to protect yourself and others from getting the virus."
There has been a high uptake rate for the vaccine but some are still missing out.
Almost 60% of pregnant women have been vaccinated but those who have become pregnant recently may not have sought the jab yet.
Dr Smithson added: "We know that flu can have serious consequences for both a pregnant mother and her baby. However, there is a wealth of evidence to show that the vaccine is safe and effective at all stages of pregnancy and that it also protects both mother and baby for the first few months after birth, a particularly vulnerable time."