Hartlepool Borough Council said this week that latest statistics show that the current seven day rate of infection for the town is 180 people per 100,000 – up from 102 per 100,000 the previous week.
But the local authority says the actual number is thought to be much higher due to current “limited testing arrangements”.
Two sub-variants of the Omicron strain of Covid – BA.4 and BA.5 – are said to be driving the current increase.
Craig Blundred, Hartlepool Borough Council’s director of public health, said: “Covid vaccines continue to offer good protection against serious illness, and people should ensure they have received all of the jabs they are entitled to.”
He said it was important that people continue to take steps to try to limit the spread of the virus, particularly amongst vulnerable groups of people.
Mr Blundred added: “Public health advice is to get vaccinated and to wear a mask, especially in crowded spaces.
"If you are meeting with others make sure you let fresh air into the premises and always practise good hygiene such as washing your hands regularly. If you cough or sneeze always cover your mouth and nose.
“If you have symptoms of Covid or a positive Covid test, follow government guidance by trying to stay at home and avoiding contact with other people until you no longer have a high temperature (if you had one) or until you no longer feel unwell.
"If you test positive, try to stay at home and avoid contact with other people for 5 days after taking the test.”
Nationally, a total of 2.3 million people in private households are estimated to have had the virus in the week to June 24.
That was up by 32% from 1.7m the week before, according to the Office for National Statistics (ONS).
Hilton Heslop, from North Tees and Hartlepool NHS hospital trust, told Stockton’s latest health and wellbeing board that staffing is being impacted by people with Covid passing it on before they realise they are infected.
However, Hartlepool’s current infection rate is significantly down from that in early January this year when it was more than 3,500 cases per 100,000 people.