Covid Situation Report: Jul 18, 2024
Update on Covid providing information on positivity and hospital admissions for England and its regions. This post is best viewed using the browser or Substack app.
Introduction
This weekly Covid Situation report was originally posted on my substack ‘Seeing the Forest for the Trees’ where I publish articles on Covid and other topics. You can access my substack at the following link.
A reminder that not all of the data previously included in the situation update is now available on a weekly basis. Where relevant, changes to the content and data sources have been noted.
This week's report contains data on weekly Covid hospital admissions from the UKHSA surveillance report, which is now released biweekly. Additionally, it includes case rates from the UKHSA Covid dashboard. The report also provides an update on deaths due to Covid in England and Wales.
Summary.
While last week's data suggested that Covid levels had likely peaked, this week's figures indicate a resurgence, with rises in test positivity, weekly hospital admissions, and case rates.
In the past two weeks, the positivity rate for Covid has once more started to increase following a slight fall. Positivity rates remain highest in the older age groups.
In the past four weeks, weekly hospital admission rates for Covid have stabilised but at levels approaching the Winter 2023 peak.
The recent increase in daily case rates has continued across all regions, with the North East experiencing the most significant rise.
While this year's deaths due to Covid are significantly lower, the recent rise in Covid levels has led to a rise in deaths due to Covid.
It now seems likely that this summer wave is continuing, indicating that Covid is not yet a seasonal disease and we are likely to experience further waves as new variants emerge and immunity levels wane.
As always, it’s important to remember that the risk of hospitalisation from Covid infection increases significantly with age and for those immunocompromised. Also Long Covid remains a risk for all as shown by the recent ONS report. Therefore, it is prudent to take appropriate measures such as self-isolating when experiencing Covid symptoms and enhancing ventilation or wearing masks whenever possible.
For those who are interested, I recently published an article covering the ONS data on Long Covid in more detail which can be found here. Also a comprehensive review of the evidence in support of wearing masks is available here.
Status of main respiratory diseases in England
This section starts with the latest available data on positivity rates for primary respiratory infections in England. It is important to understand that positivity differs from prevalence, which refers to the overall percentage of COVID-19 in the general population. Appendix 1 provides a more detailed explanation of the difference and why positivity rates are a useful indicator of trends in Covid infection levels
The chart below displays the test positivity rates for the main respiratory illnesses in England, including Flu, Covid, RSV, and Rhinovirus.
Over the past two weeks, the Covid positivity rate has again increased slightly and has reached its highest level for 18 months at 13.2% for week ending Jul 14 confirming the resurgence of Covid levels in the general population. This is an important reminder that Covid is not yet a seasonal illness and we are likely to experience further waves as new variants emerge and immunity levels wane.
Meanwhile, the flu positivity rate has continued to fall and remains significantly lower than that of Covid. Additionally, RSV rates have dropped to very low levels, accompanied by a fall in Rhinovirus rates.
The next chart shows the trend for Covid positivity rate by age. Hover your cursor over one of the chart lines to display the positivity rate for all ages. For comparison the grey line shows the positivity rate for all age groups.
The chart clearly indicates that test positivity rates are highest among individuals aged 65 and older although there has been a notable increase in the very youngest age group in the past two weeks. It is important to note that the majority of tests are now conducted on hospital patients, who are disproportionately older since they are more likely to be hospitalised due to Covid.
The final chart in this section shows weekly hospital admissions per 100,000 people in England for the main respiratory diseases.
Consistent with the test positivity rate data, the past two weeks have seen weekly hospital admission rates for Covid increased slightly, and are now approaching the levels seen during the winter wave of infections. Note that hospital admission data for Flu and RSV is no longer published.
Although age-specific data for hospital admissions are no longer released, earlier statistics on Covid hospital admissions and the current test positivity rates by age indicate that the rise in hospitalizations will primarily impact the over 65 year olds.
It's important to note that while testing policies have been updated from April 1, 2024, the guidelines for testing patients showing Covid symptoms or when a positive result would change the patient's treatment remained unchanged. Consequently, the number of Covid hospital admissions should be a dependable indicator of the virus's prevalence in the community for the period shown in these charts.
Covid hospital admissions and bed occupancy
This section gives a more detailed examination of the most recent daily Covid data for hospitals in England.
NHS England stopped the weekly publication of data used to create these dashboards from April 4, 2024 and have moved to a monthly publication schedule. The next update will be on August 8, 2024 covering July Covid hospital admissions and bed occupancy.
Covid case rates
The UKHSA Covid dashboard continues to publish daily case rates on a weekly basis. As the majority of testing now occurs in hospitals or under medical supervision, these rates should closely align with hospital admissions. However, a comparison of daily case rates and daily admissions shows that this is not the case.
Appendix 2 indicates that although Covid case rates typically reflect the pattern of hospital admissions, there is a notable discrepancy in the magnitude of changes, with admissions experiencing a more pronounced fluctuation than case rates. Therefore, while case rates are helpful in signalling the general trend of Covid within the population, they do not precisely represent the degree of change.
The first chart in this section shows daily case rate per 100,000 individuals.
The chart indicates that the rise in Covid case rates has persisted and continues to be at levels higher than the May peak. However, for the reasons outlined above an in Appendix 2 it is not advisable to compare with the Winter 2023 peak.
The next panel chart in this section shows Covid rates for the regions of England. Hover your cursor over one of the chart lines to display the admission rates for all regions.
The panel charts show that the recent surge in case rates across all regions has continues with the the North East region seeing the sharpest rise.
Covid Deaths in England and Wales
The Office of National Statistics (ONS) publishes weekly reports on the number of deaths recorded on death certificates that are due to Covid or where Covid was involved. The data available is for both England and Wales.
The following chart shows a comparison of weekly registered deaths due to Covid in England and Wales for 2023-24, represented in brown, against the previous year, illustrated in blue. The light green shaded area indicates weeks when deaths in 2022-23 were lower than this year, while the light red shaded area denotes weeks when deaths were higher this year. It excludes deaths where Covid was mentioned as a contributing factor on the death certificate.
In the week ending July 5, 2024, there were 114 deaths due to Covid in England and Wales (1.1% of all deaths reported), with an additional 171 deaths where Covid was noted as a contributing factor. This marks the second consecutive week where Covid-related deaths have surpassed those of the corresponding weeks in 2023. Despite this recent uptick, the weekly death toll for 2023/24 has been considerably lower than the previous year. Over the 12 months leading up to July 5, 2024, there were 7,104 deaths due to Covid, compared to 15,796 in the preceding 12 months.
In conclusion
Despite the reduced level of data now published, the available information indicates that the summer wave in Covid levels has not yet peaked.
Deaths due to Covid are much lower this year although there has been a slight increase in the past month and levels are above those in July 2023.
As always, if you have any comments on this Covid Situation Report or suggestions for topics to cover, please post a message below
Appendix 1. Test positivity rates and prevalence
Positivity rates are derived from the results of hospital laboratory tests conducted on patients exhibiting symptoms of respiratory diseases. Test positivity is the percentage of patients who test positive for Covid of the total number of patients tested. Since the individuals tested for this measure are not a representative sample of the general population it differs from prevalence, which is derived from a representative sample of the population.
Test positivity rates, while not directly estimating the number of Covid infections in the general population, can be a valuable indicator of the infection trend. The panel chart below compares the weekly test positivity rate among hospital patients with respiratory symptoms to the prevalence of Covid in the general population, as reported in the Winter Infection Survey.
The chart shows that the weekly test positivity rates for patients with symptoms of respiratory infections follows the same pattern as the prevalence for Covid reported by the Winter Infection Survey. Since the Winter Infection Survey is based on a representative sample of the general population this supports using test positivity as a useful proxy for infection trends.
Appendix 2. How reliable are Daily Covid Case Rates?
The UKHSA Covid dashboard continues to publish daily case rates on a weekly basis. As the majority of testing now occurs in hospitals or under medical supervision, these rates should be closely aligned with hospital admissions and the positivity rate of tests.
The following panel chart in this section tests that assumption by comparing the daily case rate per 100,000 individuals, shown in red, with daily hospital admissions for Covid reported by NHS England, depicted in blue.
The chart shows that while Covid case rates generally mirror the pattern of Covid hospital admissions, there is a significant disparity in the scale of changes. The grey shaded areas on each chart highlights the difference between the peak of the winter wave and the recent peak in June. Case rates experienced a 64% decrease, whereas hospital admissions saw a reduction of only 32% between the winter and June peaks.
In conclusion, although case rates are useful for indicating the overall trend of Covid in the population, they do not accurately reflect the extent of change. The likely reason for this is that testing levels have decreased by about a half since January.
So grateful someone gives us this information so we can make decisions about what we do. If only the BBC (which I normally love) was as helpful
Since replies are turned off on Professor Greenhalgh's Long COVID article, I had to quote restack it instead https://substack.com/@bristoliver/note/c-64113725