Adroddiad sefyllfaol COVID-19: 29 Gorffennaf 2021

Y pwyntiau allweddol i’w nodi

O 24 Gorffennaf ymlaen, mae Cymru ar Lefel Rhybudd 1. Bwriedir symud Cymru i Lefel Rhybudd 0 ar 7 Awst.

Mae trosglwyddiadau cyffredinol COVID-19 wedi lleihau ledled Cymru, ond mae canran y bobl sy’n profi’n bositif wedi parhau’n gyson. Mae amcangyfrif consensws y Gyd-ganolfan Bioddiogelwch (JBC) ar gyfer y rhif atgynhyrchu yng Nghymru rhwng 1.0 ac 1.3, tra mae amcangyfrif Iechyd Cyhoeddus Cymru (PHW) oddeutu 0.8. Ffynhonnell: JBC/ PHW (28/7/21). Sylwer bod fel arfer oedi o 2-3 wythnos yn amcangyfrif JBC a bod oedi yn achos amcangyfrif PHW, sy’n defnyddio methodoleg wahanol, o tua 1 wythnos. Sleid 3, Ffynhonnell: PHW.

Mae’r pwysau sydd ar y GIG oherwydd COVID-19 wedi bod yn cynyddu’n raddol dros yr wythnosau diwethaf. Ar 28 Gorffennaf 2021, roedd 192 o gleifion sy’n gysylltiedig â COVID-19 (cleifion y mae amheuaeth bod ganddynt COVID-19, achosion a gadarnhawyd a chleifion sy’n gwella) yn defnyddio gwely mewn ysbyty, sydd wedi cynyddu 16 ers yr wythnos flaenorol. Mae 19 o gleifion y mae amheuaeth bod ganddynt COVID-19 neu y cadarnhawyd bod ganddynt COVID-19 mewn gwelyau gofal critigol yng Nghymru. Cyfanswm nifer y cleifion mewn gofal critigol oherwydd COVID-19 ac am resymau nad ydynt yn gysylltiedig â COVID-19 yw 155, 3 yn fwy nag uchafswm capasiti gofal critigol cyn y pandemig o tua 152.

Ar 27 Gorffennaf 2021, mae’r achosion a gadarnhawyd o’r amrywiolyn Delta, sef yr amrywiolyn amlycaf, yn 9,465 yng Nghymru (mae hyn wedi cynyddu 1,648 ers yr wythnos flaenorol). Canfuwyd un achos newydd o Alffa yr wythnos hon. Ni chanfuwyd unrhyw amrywiolyn sy’n peri pryder arall. O’r 9,465 o achosion a ganfuwyd hyd yma, roedd 46% o’r achosion mewn unigolion nad ydynt wedi’u brechu, roedd 30% wedi derbyn 1 dos ac roedd 24% wedi derbyn 2 ddos. Sylwer efallai fod y data hyn yn cynnwys brechiadau nad oes 14-21 o ddiwrnodau, fel sy’n angenrheidiol i ddarparu’r amddiffyniad gorau posibl rhag COVID-19, wedi pasio ers iddynt gael eu derbyn. O’r 9,465 o achosion, cafodd 129, neu 1.4%, eu derbyn i’r ysbyty. Ffynhonnell: PHW.

O ran brechu, ar 28 Gorffennaf 2021, mae cyfanswm o 4.33 (+0.09) miliwn o ddosau o frechlyn COVID-19 wedi cael eu rhoi yng Nghymru. O’r rhain, dosau cyntaf oedd 2.29 (+0.01) miliwn ac ail ddosau oedd 2.04 million (+0.08), sy’n golygu bod 80% o bobl 18 oed a hŷn bellach wedi’u brechu’n llawn. Mae SAGE yn amcangyfrif ei bod yn ofynnol i gwmpas imiwnedd fod yn 80% o leiaf, ar gyfer yr amrywiolyn Delta (gan gynnwys pobl o dan 18 oed). Ar sail hynny, os na cheir unrhyw ymddygiadau amddiffynnol eraill, ni fydd y niferoedd presennol sydd wedi’u brechu yn diogelu ar lefel y boblogaeth gyfan. Ffynhonnell: PHW, SPI-M-O.

Dangosyddion allweddol

Mae nifer o ddangosyddion allweddol yn dangos cynnydd, yn dilyn cyfnod lle cafwyd lefel isel o drosglwyddiadau ym mis Ebrill a Mai. Mae’r achosion yn dechrau lleihau.

Sylwer bod y saethau yn cynrychioli newid mewn cymhariaeth â’r wythnos ddiwethaf.

1. Mae’r data diweddaraf a gafwyd o’r Arolwg Heintiadau COVID-19 ar gyfer y cyfnod o 18 Gorffennaf 2021 i 24 Gorffennaf 2021.
2. Y cyfartaledd treigl saith diwrnod hyd at y dyddiad presennol o gleifion y cadarnhawyd bod ganddynt COVID-19 – nid yw’n cynnwys cleifion y mae amheuaeth bod ganddynt COVID-19 neu sy’n gwella.
3. Mae data marwolaethau diweddaraf ONS hyd at 16 Gorffennaf 2021 (yn hytrach na 24 Gorffennaf 2021) ar gyfer y gwerth cyfredol. Defnyddir data hyd at 9 Gorffennaf 2021 ar gyfer y newid ers yr wythnos flaenorol.

At a Wales level, on 23 July 2021, the 7-day rolling incidence of COVID-19 cases has decreased since last week. The percentage of people testing positive for COVID-19 has remained steady since last week (slide 2). 

The JBC consensus estimate of Reproduction number (Rt) is between 1.0 and 1.3 (as at 28 July 2021), with a doubling time of 18 days to flat. When we look at reproduction numbers using PHW positive test data only (see second table below) - a more timely estimate but limited by variation in testing - we see an Rt of 0.8 for Wales and a national halving time of 67 days. When R is below 1.0, the pandemic is shrinking. Rt is highest for Swansea Bay health board at 1.0. PHW central estimates of halving times at health board level range from 31 to 79 days. Source: SAGE/ PHW 

7-day cumulative case incidence in Wales has decreased by a fifth in the last week. Case incidence has fell to 156.9 per 100,000 population in Wales compared with 190.1 per 100,000 population last week. 

Case incidence is decreasing in almost all local authorities. Case incidence is above 100 per 100,000 population for 16 of the 22 local authorities. Local authorities with the highest case incidences are Denbighshire and Conwy at 423.2 and 318.3 per 100,000 population, respectively, although case incidence is decreasing in these areas. Case incidence is increasing for Merthyr Tydfil and Ceredigion.

Case incidence is highest in those aged 10-19 and 20-29. Case incidence has decreased throughout the week in these age groups. Case incidence is highest for the Betsi Cadwaladr health board. Case incidence is stable or decreasing in all health boards.  

The table below provides estimates of doubling and halving times based on PHW COVID-19 positive test data. In this table, doubling times are positive, whilst halving times are negative. The 95% confidence intervals are showing in brackets after the central estimate. An asterisk (*) means that there are small numbers and estimates should be treated with caution. Local health board level estimates of Rt and halving times will be unstable when incidence is low. 

Cases per 100k (PHW Data) (7 day rolling sum)

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Cases per 100k by age (PHW Data) (7 day rolling sum)

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Data as at 12:00PM 28 July 2021 unless otherwise specified.

COVID-19 pressure on the NHS has been steadily increasing over recent weeks. As at 28 July 2021, there were 192 COVID-19 related patients (Suspected, Confirmed and Recovering) occupying a hospital bed. This compares to 176 (16 more occupied beds) on 21 July 2021. Confirmed patients accounted for 139 of the total occupied beds, and are at similar levels to late March 2021.  

There are 19 patients with Suspected or Confirmed COVID-19 in critical care beds in Wales. This is 145 lower than the maximum COVID-19 position of approximately 164. The total number of patients in critical care for both COVID-19 and non-COVID-19 stands at 155, 3 more than the historic maximum critical care capacity of approximately 152.

In the latest National Situation Background Assessment Recommendation (SBAR) report covering the week of 19 July 2021 to 25 July 2021, IMTs reported 91 care homes were in 'red' status (an ongoing outbreak/incident reported within the last 7 days), with 2 health boards reporting having no care homes in 'red' status. This is compared with 69 care homes in 'red' status in the 7 days up to 18 July 2021. Source: National SBAR

Confirmed hospital occupancy (7 day rolling average)

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Overall invasive ventilated bed occupancy (7 day rolling average)

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Hospital bed occupancy for suspected and confirmed COVID-19 positive patients (7 day rolling average)

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Invasive ventilated bed occupancy for suspected and confirmed COVID-19 positive patients (7 day rolling average)

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Number of adult care homes reported an ongoing outbreak/incident (last 7 days)

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Childcare settings

The latest National Situation Background Assessment Recommendation (SBAR) report covering the week of 19 July to 25 July reported 6* new clusters in childcare settings last week across 5 health boards, compared to 2 new clusters reported the previous week. 

Schools

The number of new and on-going school clusters overall has reduced significantly since last week, though a significant number of schools broke up for the Summer term that week so this would have an impact on the reduction. There were 34* new and 69* ongoing clusters associated with schools reported by IMTs last week. 

 49* are attributed to school settings and 26* to household, social or extra-curricular activities. Source: National SBAR 

*Figures do not include Wrexham, Gwynedd or Cardiff & Vale data

School Attendance

The 2020/21 academic year ended on 20 July 2021. The majority of schools had no pupils present on 19 to 20 July due to INSET days. Therefore, this headline presents data up to 16 July only. The figures for the latest two weeks have been revised. An average of 77% of all pupils were present in school over the week of 12 July to 16 July.   Source: Stats Wales

Absence due to Covid

An average of 6% of all primary age pupils and 13% of all secondary age pupils were absent due to a known COVID-19 related reason between 12 July 2021 and 16 July 2021.  For all schools reporting, this is the final publication of the academic year. Source: Stats Wales

School reporting on hold

School reporting is on hold due to summer holidays - the available data is challenging to interpret, because a large proportion of staff and pupils are not in school.

There is a 29% increase in overall travellers. There were 37 positive travellers (0.49% positivity) compared with 76 (1.29%) last week. The positivity rate amongst green arrivals was 1.15% (down from 2.28% last week). The positivity rate amongst amber arrivals also reduced to 0.28% (0.64% last week). There were 692 exempt travellers (9.1%), up from 533 (9.0%) last week.

Fully vaccinated arrivals from amber list countries will no longer be required to isolate at home. Arrivals from France are required to isolate due to concerns over the Beta Variant. 

7,621 total travellers this week (5,893 last week): 

• Red: 167 (167, same as last week) 
• Amber: 5,759 (3,892 last week) 
• Green: 1,650 (1,752 last week) 

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Source: Home Office

Please note that the data provided by the Home Office is derived from Passenger Locator Forms (PLF) which are self-completed by travellers. As such, data may contain inaccuracies. Due to the limitations associated with data capture and legislation, some minor discrepancies may be present in the data.

Mobility data by location of trip, Welsh local authorities

Further increases in mobility were observed compared to the previous week. Overall mobility decreased from half term week (end of May/early June), but has been increasing again since mid-July. The baseline for much of the data is during January to February 2020 and changes are relative to that period. It is not possible to determine if mobility is higher/lower than would have been expected prior to the pandemic as data for 2019 or earlier years is not published.

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Adherence

The most recent IPSOS MORI data for the period 16 – 19 July for Wales reports that perceptions of threat posed to the country by coronavirus has risen from 41% to 53%. Those only leaving home for essential journeys remained stable at 25%, lowest since the survey began in March 2020. 

The latest results from the Public Engagement Survey on Health and Wellbeing during Coronavirus Measures (5 – 14 July) reports 85% of people said they understand current restrictions in Wales ‘very well’ or ‘fairly well’ and 37% of people said they were following coronavirus restrictions ‘completely’, down from 43% (21 – 27 June). It should be noted that this is self-reported adherence and will be affected by individuals’ understanding of the rules and circumstances that apply to them. 

Results from the Coronavirus (COVID-19) Infection Survey, 18 July to 24 July 

The percentage of people testing positive has decreased in Scotland in the most recent week and has continued to increase in England, Wales and Northern Ireland, although the rate of increase seems to be slowing in England. 

It is estimated that an average of 18,800 people in Wales had COVID-19 (95% credible interval: 12,700 to 26,000), equating to around 1 in 160 people or 0.62% of the community population (up from 0.47% last week). This compares to around 1 in 65 people in England, around 1 in 110 people in Scotland, and around 1 in 65 people in Northern Ireland.

Source: Office for National Statistics COVID-19 Infection Survey.

Positivity rates (%) across UK countries up to 24 July 2021

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Vaccination and antibody status of individuals aged 16 and over in Wales

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Immunity estimates and antibody status of individuals aged 16 and over in Wales

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The COVID-19 vaccination rollout of first doses has slowed in Wales, but rollout of second doses continues to progress well. As at 24 July 2021, 87% of people aged 16 and over had received at least one COVID-19 vaccine dose in Wales. 11% of people aged 16 and over had exactly one vaccine dose and 76% were fully vaccinated. 

Between 28 June and 4 July 2021, the ONS COVID-19 Infection Survey estimated that 92.6% of the community population aged 16 and over in Wales tested positive for COVID-19 antibodies.

As at 24 July 2021, it is estimated that 82% of people aged 16 and over in Wales had some immunity against COVID-19 infection. The lower and higher estimates of immunity are 64% and 85% of people aged 16 and over in Wales. If no vaccines had been administered, it is estimated that 34% of people aged 16 and over would be immune. These estimates assume 84% of natural infections lead to immunity, but do not account for waning immunity. [Source: SIREN study paper, The Lancet, published 9 April 2021]

It is currently estimated that over 80% (may be closer to 90%) of the population, spread evenly across Wales, must be immune to COVID-19 before population immunity effects would be observed. [Source: TAG advice on the Delta variant, published 18 June 2021] Note that the immunity estimate of 82% is for individuals aged 16 and over, not the total Wales population, and varies across age groups. 

Differences between antibody presence and immunity estimates include:

• ONS antibody estimates are based on study participants who have volunteered for the study and estimates are extrapolated.
• ONS estimates are based on the 16+ community population, which excludes people in care homes or hospitals. Immunity estimates are based on the whole 16+ Wales population.
• While antibody protection doesn’t equal immunity from infection, it does give a useful indication of the level of protection from infection in the Welsh population. 
• Antibody estimates use 2019 mid-year population estimates while we use 2020 estimates.

Source: ONS COVID-19 Infection Survey, PHW, SPI-M, Swansea University modelling

Based on the current rates observed with current restrictions:

Cases 

The probability of incidence reaching greater than 200 per 100,000 between 8 August and 14 August is below 80% for all local authorities. The figure illustrates the probability (between 0 – 100%) of incidence being greater than 200 per 100,000. Source: Imperial College London

Probability of greater than 100 per 100,000 cases by local authority

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1 - 7 August and 8 - 14 August

Deaths per day

SPI-M's consensus view is that the number of deaths in Wales will remain low compared with previous waves over the next four weeks. Source: Modelled medium term projections, SAGE/SPI-M, 28 July

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Hospitalisations per day

Projected to level off at around just over 20 per day over the next three weeks. Source: Modelled medium term projections, SAGE/SPI-M, 28 July

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These projections are based on current trends and will not fully reflect the impact of policy or behavioural changes over the past two to three weeks. The projections include the impact of vaccines, but cannot capture any future increases in transmission resulting from new variants. They are not forecasts or predictions. 

Key risks

Transmissions, incidence and prevalence

Overall transmission, percentage of people testing positive is slightly decreasing since last week. 

Trends vary across health boards and local authorities.

NHS Capacity

COVID-19 pressure on the NHS has been steadily increasing over recent weeks. Invasive ventilated bed occupancy and hospital bed occupancy for COVID-19 related patients is increasing.

Mortality

Low numbers of deaths in the most recent week, although this is increasing.

Variants

Wales has 9,465 confirmed cases of the more transmissible Delta variant (an increase of 1,648 from the previous week). Delta remains the dominant variant of COVID-19 in Wales.

Immunity and vaccines

4.33 (+0.09) million doses of COVID-19 vaccine have been given in Wales, of which 2.29 (+0.01) million were first doses and 2.04 million (+0.08) were second doses. Around 82% of people aged 16 and over have some immunity in Wales.

International

There is an increase in traveller numbers this week, however positive rates are relatively low.

Key sources for this update

Technical Advisory Cell brief

COVID infection survey results

Public Health Wales

Hospital occupancy

Higher Education

School attendance

Public Health England VoC Technical Briefing