People with long-term health conditions have been warned to protect themselves from influenza this year.
By 2017, about half of NHS flu vaccines eligible for vaccination in Wales were missing, and public health in Wales warned that certain health conditions put people at greater risk.
These include diabetes, heart, liver, and kidney disease.
Influenza spreads through droplets, which are sprayed in the air when an infected person coughs or sneezes.
Direct contact with contaminated hands or surfaces may also transmit contamination.
The chief nurse responsible for Wales, Jean White, said: "There is available protection and an annual influenza vaccine is the best way to avoid yourself from influenza that can aggravate your condition or lead to other dangerous complications .
"Please do not risk – make sure you get your vaccine this year."