The proportion of vulnerable people having the flu vaccine is low among those people in greatest danger in Brighton and Hove, health chiefs have warned.
Tens of thousands lack protection, according to the Brighton and Hove Clinical Commissioning Group (CCG).
The warning came as cases of Australian flu are on the rise.
While the vaccine may not protect against every strain of flu, medical experts say that it still provides crucial protection against common strains to those most at risk of serious illness or death.
The CCG said: “Local people in danger of getting gravely ill if they catch the flu are being urged to get their free flu jab by the local NHS as it is not too late to get protected, after figures showed tens of thousands of them were missing out.
“The take up of the vaccine in Brighton and Hove is lower than the national averages, with almost 20,000 (or 60 per cent) of people under 65 in the city with a long-term condition missing out on their free flu jab.
“Furthermore, over 1,900 pregnant women have not claimed their free vaccination, with only 37 per cent having their jab.
“Anyone at risk of complications can receive the flu vaccine for free through their GP and from their local high street pharmacist.
“Parents of children can speak with their GP about how to get the vaccine for their children.
“The NHS in Brighton and Hove is urging people at risk of severe illness from flu – including those aged over 65, under 65 with a long-term condition, young children and pregnant women – to get their free flu vaccine now as it is not too late to receive it.”
Katie Stead, a GP (general practitioner) and the clinical lead for public health for the Brighton and Hove CCG, said: “We are urging those at risk of complications to get their free flu jab now as it’s still not too late to claim your free flu jab to protect you and your family.”
Dr Stead said: “The flu jab remains the best way for those who are at the highest risk to protect themselves from the severe effects of the influenza virus.
“The low uptake of the free vaccine increases the risks for thousands of vulnerable patients in our city at risk of medical complications if they get the flu, as well as massively increasing winter pressures on the NHS.”