Figures from Public Health Wales (PHW) show that there were 234 new cases of Covid-19 recorded on Monday, September 21.
That is the highest number of cases recorded in a single day since April 22, close to the peak of the pandemic, when 253 were recorded.
However significantly more tests are being done today, with 9,850 test results reported today, compared to 1,049 on April 22.
It comes as the Welsh Government has announced Bridgend, Merthyr, Newport and Blaenau Gwent will go into local lockdown from 6pm on Tuesday.
The latest figures show the infection rate in Merthyr Tydfil has hit a new high of 102.8 infections for every 100,000 people in the last week – significantly the highest rate in Wales. Rhondda Cynon Taf remains the second hardest hit area with 83.3 infections for every 100k people. Blaenau Gwent has hit 60 and Bridgend 53.
Rhondda Cynon Taf (RCT) had the highest number of new cases with 40, followed by Cardiff with 31, Blaenau Gwent with 20, Caerphilly with 15, Bridgend with 14, Merthyr Tydfil, Swansea and Carmarthenshire with 12 each and Newport with 11.
Flintshire had 10 new cases, the Vale of Glamorgan had eight, Anglesey had seven, Denbighshire and Neath Port Talbot had six, Pembrokeshire and Torfaen had five, Monmouthshire and Gwynedd had four, Conwy had three, Wrexham had two and Ceredigion and Powys had one each.
Over the course of the last seven days, Merthyr Tydfil had the highest number of cases per 100,000 population with 102.8, followed by RCT (83.3), Blaenau Gwent (60.1), Caerphilly (53), Bridgend (53) and Newport (45.3).
These are the areas with the highest seven-day rolling totals for new cases. All figures are reported as cases adjusted for population (per 100,000 people):
The latest figures come after it was announced that Newport, Bridgend, Merthyr and Blaenau Gwent will all be subject to the same local lockdown restrictions as RCT and Caerphilly from 6pm on Tuesday.
“Because of the developing situation in these four local authority areas, we will be introducing local restrictions in these local authority areas from 6pm tomorrow,” said Health Minister Vaughan Gething on Monday.
“This will mean a large part of the population of south Wales – and the south Wales Valleys – will be subject to local coronavirus restrictions.
“We will hold an urgent meeting tomorrow with all local authorities, health boards and police forces in south Wales – from Swansea to the border with England – to discuss the wider regional situation and whether further measures are needed.”
News – Wales sees most new Covid infections in a day since April