WHAT DOES RISE IN VIRUS CASES MEAN?
THE latest rise in coronavirus cases has alarmed the Government so much it has introduced more restrictions across Wales in a bid to protect public health.
Every day it seems we are bombarded by new statistics and different measures telling us how coronavirus is spreading across the country.
But what exactly do those measures tell us and is the recent spike in cases really as bad as it sounds?
One lesson from the early part of the pandemic was how data here in Wales and the UK could help predict where we might be headed. At the time, we compared our situation with Spain and Italy where the pandemic was a few weeks ahead of us
It could be time to start doing that again, as the medical director for the Aneurin Bevan health board pointed out this week. Dr Sarah Aitken said she was keeping an eye on rising Covid cases across much of Europe, with France reporting a 14-day cumulative number of Covid-19 cases per 100,000 of 140, Spain reporting 266 and Italy 32. The UK is currently at 42 cases per 100,000.
Perhaps of greatest significance is the European data pointing at a rise in hospitalisations in France, said Dr Aitken.
That doesn’t necessarily mean it’s time to panic, however, as while cases are certainly on the rise in Wales, it’s important to note they’re still quite low as a percentage of tests and we’re not yet seeing a rise in deaths as we did last time around.
Here are key things to consider.
The peak was underestimated in the first place
The confirmed cases chart is one we see regularly and charts the number of positive Covid-19 tests every day in Wales.
At the start of April, there were days when nearly 400 new cases a day were recorded. The level of infections in the past few days therefore appears to be nearly a third of that peak and certainly more than the single figures being reported at the start of August.
But at the start of the pandemic, Wales and the UK was only really testing those patients in hospitals. There was limited testing capacity and therefore the number of confirmed cases may not have been representative of what was happening in the communities across Wales.
Now we have mass testing in the community. Comparing numbers now to numbers during the peak isn’t really a fair comparison. There are two studies that back this up.
The London School of Hygiene and Tropical Medicine estimates there may have been as many as 100,000 cases a day across the UK at the end of March yet mass testing in the community only started in the second half of May.
And the Office for National Statistics data indicates a much larger proportion of cases are now being picked up compared to earlier in the pandemic when maybe only 5% of cases were being detected.
In essence then, the number of cases may be rising in Wales but the level of infection being seen is still very low compared with the peak from April.
We are testing more
The number of tests carried out on a daily and weekly basis has steadily increased across Wales, albeit with daily fluctuations.
More testing centres have opened and lab capacity to process the tests has been increased. This gives us a better basis for looking at how the virus is circulating in the community.
But we have to factor in that big increase in testing. At the start of April, there were barely 1,000 tests being carried out in Wales. In the past week, there have been days where there have been nearly five times that many.
Adjusting for the numbers of tests carried out and calculating the percentage of positive tests gives a slightly different picture.
It is still a significant rise but it is slightly slower and seems to have happened more recently.
Welsh resources have been focused on areas with the highest rates, such as in Caerphilly and the lower Rhondda. It makes sense then that by looking in areas with highest rates of infection, you are more likely to get positive tests.
It is telling that over the past week to Thursday, nearly half of all new cases were in just three local authority areas: Caerphilly, Merthyr Tydfil and Rhondda Cynon Taf. These three areas also have the highest rates of confirmed cases per 100,000 population.
Why are there more cases in some areas?
Caerphilly has seen the highest rise in the past week in Wales. On Thursday, it reported 91.1 cases per 100,000 people and, due to the speed of the upsurge in cases, it became the first area of Wales to be put into a local lockdown. By Friday it jumped to 96.6.
It is the second hardest hit part of the UK for infections in the last week, after Bolton, Greater Manchester, which tightened its local restrictions.
Dr Rhianwen Stiff, consultant at Public Health Wales, said there had been a “significant rise” in positive coronavirus cases in Caerphilly county and the blame was squarely put on people not following the rules.
Dr Stiff said: “Our investigations indicate that a lack of social distancing by a small group of people of all age groups in a range of different locations has resulted in the spread of the virus to other parts of the population,” she said.
It appeared people had taken advantage of the easing of the lockdown and “seem to have forgotten the importance of social distancing” resulting in possible transmission in the wider community.
Cases in Porth and Penygraig were behind a rise in Rhondda Cynon Taff, which has seen a rise in its case rate to 37.3 cases per 100,000 over the past week.
On Thursday evening, the council issued a plea for residents to follow voluntary advice to restrict their use of public transport, work from home as much as possible, wear masks while in work, supermarkets and other indoor locations and not to visit care homes.
Hospital admissions aren’t rising as much as cases
Hospital admissions have yet to show any statistically significant uptick mirroring the spike in cases, although PHW data is only published for the week ending September 6.
However, on Thursday, NHS Wales data revealed 72 people with suspected and confirmed Covid-19 have been admitted to hospitals in the Cwm Taf Morgannwg health board area between September 1 and September 8.
This was double what it had been the previous week and was the highest number of admissions since the beginning of August.
At the same time, the health board which covers the Caerphilly area – Aneurin Bevan University Health Board – also saw its biggest number of hospital admissions for more than two months, with 76 people admitted in the seven days up to Wednesday.
For these two health board areas, it means hospital admissions are around half of what they were during the peak. But elsewhere, across Wales, admissions are a small fraction of the number of admissions back in April.
One theory is that more testing is uncovering a larger number of mild cases which don’t need treatment. Another is that more of the cases are among younger people, who are less likely to become very ill.
Two intensive care consultants – Dr David Hepburn and Dr Matt Morgan – have said they haven’t had any Covid patients admitted in the past month, although they are fearful this could change if a “tipping point” is reached pushing infections back into the older population.
Speaking this week, Dr Aitken said: “The virus spread in France among the younger age groups like it has done here.
“Although it’s much less likely to lead to hospital admissions, it’s urgent that we stop the spread as soon as we can because if the virus spreads into the elderly population it will lead to hospital admissions.
“That’s what we are seeing in France now.”
The rise in the two health board areas shows the virus could be taking hold in the community again, and could quickly escalate. On Friday, England recorded a total of 3,539 new Covid-19 cases – the highest daily figure since May 17.
Public Health England’s medical director Professor Yvonne Doyle warned that there are now “worrying signs” of infections among the elderly.
She said: “Although younger people continue to make up the greatest share of new cases, we’re now starting to see worrying signs of infections occurring in the elderly, who are at far higher risk of getting seriously ill.”
More young people are testing positive
Public Health Wales data shows people in the 10-29 age bracket are testing positive at higher rates than any other age group, and at higher rates than they were earlier in the pandemic.
In the first 10 days of September, that age group accounted for more than a third of all positive cases in Wales. Up until the August 1, that same age group accounted for 15% of all positive cases in Wales.
The difficulty is explaining why that might be.
It could be down to simple behaviour – that younger people are more likely to have to go out to work, go to school, live in shared housing and go out to socialise.
But it could also reflect a change in testing availability. It is a well established fact that younger people are much less likely to get seriously sick with coronavirus. Therefore, as testing was predominantly done in hospitals at the beginning of the pandemic, where many older, sicker Covid patients were being treated, and so earlier this year would not have found themselves in hospital where they would have been tested.