The first week of December brought a ‘worrying rise’ of 27% in the number of coronavirus cases, the public health agency has said.

In the seven days to Tuesday 43,103 positive tests were recorded, compared to 33,949 the week before. The trend was partly due to an 23.5% increase in testing, but the positive test rate also increased from 11.1% to 11.6% – still well above the World Health Organisation’s benchmark of 5%.

Ministers are holding another press conference on Tuesday evening when they will announce what measures will apply over the Christmas period, but changes are expected to be minimal given that the daily total has increased for six days in a row.

The daily total fell on Tuesday to 6,187, nearly 1,000 cases lower than Monday but 52% higher than the figure a week ago. The average number for the week was higher than 6,000 for the first time since November 10.

The number of patients in hospital increased for the fifth consecutive day to 1,700, an increase of 40, although intensive care patients went down from 470 to 464.

Infections are rising in all age groups, but more rapidly among secondary school-aged children. In the last week 453 out of every 100,000 people aged 13 to 17 tested positive for the virus compared to 344 the previous week. The second highest infection level was in the 18-to-24 group, with 323 per 100,000.

In the last week schools accounted for 8.5% of infections where the source has been traced, compared to 5.9% over the course of the pandemic. Just over half (52%) of people caught the virus at home, while another 21% were infected on visits to friends and family.

The virus is also spreading more widely through nursing homes, with 100 locations recording a new case last week after at least 28 days without a positive test. The equivalent number a week ago was 77.