The number of people in hospital with flu in England has fallen for the second week in a row, NHS figures show, as England’s top doctor said the health service was “far from complacent” as a cold snap takes hold.

An average of 2,676 flu patients were in hospital each day during the week ending 28 December, down 13% from 3,061 the previous week.

The figure had previously been on an upwards trend, reaching 3,140 in the week ending 14 December. Last winter, weekly flu numbers for England peaked at 5,408 patients.

A total of 128 flu patients were in critical care beds in England last week, down from 117 the previous week.

The UK Health Security Agency has issued amber and yellow cold health alerts for England as temperatures fall below freezing, which could increase the pressure on hospitals.

Prof Meghana Pandit, the NHS national medical director, said: “It is welcome news to see a drop in the number of people being admitted to hospital with flu, thanks in part to the extraordinary efforts of NHS staff with more than half a million more people vaccinated against flu compared to the same period last year.

“The NHS is far from complacent as temperatures drop, with this likely to increase pressures in the new year, and demand on services remaining high with NHS 111 services recording their second busiest day in two years on Saturday.”

The health secretary, Wes Streeting, said: “In spite of all of the challenges the NHS faces this winter, the herculean efforts of NHS staff and our investment and modernisation mean that hospital bed occupancy is lower than this time last year and ambulance handover performance is improving.

“But we still face intense pressures, and with this bitingly cold snap adding additional challenges it is more vital than ever those eligible get their flu jab and people only attend A&E in an emergency. Let’s all join NHS staff in doing everything we can to protect ourselves and our families through a difficult winter so NHS services are free for those who really need them.”

An average of 284 hospital beds were filled each day last week by patients with diarrhoea and vomiting or norovirus-like symptoms. This was broadly unchanged on the previous week’s average of 285 patients and well below the figure of 427 patients a fortnight ago.

The data has been published in the latest weekly snapshot of the performance of hospitals in England this winter.

The NHS situation report also shows that 18% of patients arriving by ambulance at hospitals in England last week waited at least 30 minutes to be handed over to A&E teams. This was down from 22% the previous week and is the lowest figure so far this winter.

Four per cent of ambulance handovers last week, or 3,359 patients, were delayed by more than an hour, down from 5% the previous week and also the lowest level so far this winter.