The high coronavirus rates in Norwich has prompted concerned health bosses to urge people with Covid-19 to make sure they isolate properly - including from their own families and housemates.
Rates have dropped slightly across Norfolk - down to 439 cases per 100,000 people in the seven days to January 16, compared to 491 the week before.
But Norwich is an exception with 629 cases per 100,000 in the past seven days, described as a "concern" by Norfolk's public health director Dr Louise Smith.
She said Norwich was a "regional outlier", with rates among over 60s a particular worry.
While she said it was not entirely clear why Norwich had more cases, she said analysis suggested part of the problem was that people who have tested positive for Covid-19 are not isolating properly from the people they live with.
Dr Louise Smith, director of public health, said 35pc of cases were now linked to where people lived – whether in their own homes or care homes.
She said it was "very clear" the new variant of coronavirus was more transmissible.
Dr Smith said: “Case figures are reducing in Norfolk, except for in Norwich, which is looking like a regional outlier.
“In Norwich, cases are also rising among the over-60s. This is very concerning, as it may lead to more hospital admissions and deaths.
It’s very easy to be wary of strangers but then drop your guard when someone you live with shows Covid symptoms.
“There are simple precautions everyone can follow, to keep yourself safe in these circumstances.”
She said: "My biggest message today is you have someone at home who has symptoms or who has tested positive please follow as many rigorous measures as you can to help that person self-isolate in your home."
She said the infected person should spend as little time as possible in rooms with others in the home.
People should eat in separate rooms, cutlery should not be shared, people should not share towels and bathrooms and surfaces should be thoroughly cleaned, she said.
Alan Waters, leader of Norwich City Council, said: “It’s frustrating for us all to see that the cases in Norwich are remaining stubbornly high – and this is despite the clear collective efforts of the majority of our residents and businesses carefully following the guidance.
“But we need everyone to hold their nerve and continue to follow the rules so we can turn the corner and see the rewards of the sacrifices we’ve all made, since we went into lockdown two weeks ago, with a reduction in cases in the city.”
Dr Smith said she did not think the high rates in Norwich were skewed by the recent outbreak at Norwich Prison, but were a case of community infection.
Stephen Evans, chief executive of Norwich City Council, said environmental health offices had been checking up on the city businesses which are open.
He said there had been good compliance, with just one case where tougher measures had been introduced the following day as a result of the visits.
Andrew Proctor, leader of Norfolk County Council, said: “I continue to be proud of how the people of Norfolk and all key agencies are working together in the face of this pandemic.
“I’m very encouraged by what we are hearing from NHS colleagues regarding the wider roll-out of vaccinations, including the new centre in the Castle Quarter in Norwich.
“The long-term way out of this situation is through vaccination. But in the meantime it’s still just as important that the guidelines of hands, face and space are strictly followed.
“It’s still early days in terms of analysing the information but we should get a better picture in coming weeks.”
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here