Covid Situation Report: Oct 17, 2024
Covid Situation Report: Oct 17, 2024
Update on Covid providing information on prevalence and hospital admissions for England and its regions. This post is best viewed using the browser or Substack app.
Introduction.
This report belongs to a weekly series summarising the Covid situation across the UK's home nations and the English regions.
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 marks the return of the UKHSA surveillance report to its weekly publication schedule, following a bi-weekly cadence over the summer. Consequently, this report includes the most recent test positivity rates and hospital admissions data for England. It also incorporates daily case rates from the UKHSA Covid dashboard, alongside the latest data for Scotland, Wales, and Northern Ireland. The report also provides a brief update on England's Autumn 2024 Covid booster campaign. Finally, the key points from a recent paper from Denmark comparing the burden of Covid and Flu are summarised
Summary.
This week's data presents a stable situation, with Covid levels remaining largely unchanged across all home nations, albeit higher than levels seen earlier in the year.
In England, the Covid test positivity rate has been stable for the past three weeks, and hospital admission rates stopped rising this week, though they are nearing the levels seen during the summer peak. Nonetheless, there is a notable regional variation, with admissions increasing in the Midlands and Northern regions, while decreasing in the Southern regions.
In addition, the daily case rates for England stopped rising towards the end of the latest week but increases continued for some regions in the Midlands and the North.
In Scotland, hospital admissions remained stable albeit at levels higher than earlier in the year whilst bed occupancy rose slightly
In the past week, Covid cases in Wales remained unchanged but hospital admissions decreased slightly.
In Northern Ireland, Flu and RSV activity continued to increase across some surveillance indicators but remained at very low levels. Covid activity remained stable.
A recent Danish study compared the impact of Covid to that of the Flu. The research established that Covid is not a seasonal disease, unlike the Flu, and is associated with more than double the number of hospitalizations and deaths when compared to Flu.
This is an important reminder that Covid is not presently a seasonal disease and may never become one. As such, we should anticipate potential future waves with the emergence of new variants and as immunity levels diminish.
Vaccination remains a powerful way to minimise the risk of Covid and the Autumn 2024 booster campaign has had a very strong start, with over 25% of the targeted demographic aged 65 years and older already vaccinated. However, there is a notable gap in vaccination coverage among those clinically at risk who are under the age of 65.
As a reminder, the NHS have reconfirmed eligibility criteria for the Autumn 2024 booster campaign which started on October 3, 2024 and will close earlier than previous years on Friday, December 20. Eligibility can be confirmed and bookings made at the following link.
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.
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.
The recent sharp rise in the Covid positivity rate has stopped and stabilised over the past three weeks, though it remains at a relatively high level that is close to that seen at the height of the summer surge. Rhinovirus rates seem to have reached their peak after a notable increase. Meanwhile, Flu and RSV rates are beginning to show signs of rising, yet continue to be at low levels.
The next chart in this section shows weekly hospital admissions per 100,000 people in England for the main respiratory diseases.
In the past week, weekly hospital admission rates for Covid have also stabilised at levels close to the summer peak whilst admissions for Flu and RSV remain low.
However, the final chart in this section indicates that while Covid admission rates across England are generally stable, there are significant regional differences.
The panel chart indicates a north-south divide, with all regions in the Midlands and the North experiencing increases in admission rates over the past week, while the southernmost regions have seen slight reductions.
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 case rates in England
The UKHSA Covid dashboard continues to publish daily case rates for England 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 Covid case rates increased lightly during the week but are now levelling off at a rate higher than observed during the peak in May and are close to the peak of the Summer wave. It is important to note, as detailed above and in Appendix 1, that comparisons with the peak in Winter 2023 are not recommended.
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 indicate that in the past week daily case rates have started to rise again across some regions, particularly in the Midlands and North East regions. This is consistent with the regional pattern seen for the weekly hospital admissions.
Scotland weekly hospital admissions and bed occupancy
Scotland continues to publish weekly data on hospital admissions and bed occupancy for Covid as well as waste water monitoring data. The dashboard for Scotland’s data can be accessed here.
The following panel chart shows the most recent data for weekly Covid hospital admissions depicted in blue, together with the number of beds occupied by Covid patients, shown in orange. The number of occupied beds represent patients being treated for Covid as well as those being treated with Covid.
The charts shows that the recent 'summer' Covid wave in Scotland led to more hospital admissions and a greater number of beds occupied by Covid patients compared to the 'winter' wave. This contrasts with England, where 'summer' hospital admissions did not surpass those seen in 'winter'.
The fall in weekly Covid admissions from the summer peak has now stopped and has stabilised, albeit at higher levels than earlier in the year. There was a slight rise in the number of beds occupied by Covid patients this week.
Scotland remains the only home nation that is monitoring Covid levels using wastewater sampling. However, wastewater data reporting is currently paused until the end of October as the responsibility for laboratory Covid water sample testing transfers from Scottish Environment Protection Agency (SEPA) to NHS Lothian.
Wales Covid cases and hospital admissions.
Public Health Wales publishes a weekly Covid dashboard, presenting key Covid hospital indicators for the preceding 90 days. This dashboard can be found here. Additionally, data regarding Covid cases detected through testing in hospitals and other medical facilities are released every week.
The following chart presents the latest data for the weekly number of cases reported.
The summer wave of cases in Wales exceeded the 'winter' wave, culminating in the highest level in more than a year. The recent surge in cases appears to have stabilised albeit at moderately high levels.
The following chart gives the trend for weekly hospital admissions in Wales.
Whilst the number of hospital admissions for Covid fell slightly this week they also remain at a moderately high level, albeit lower than the figures reported last year.
Status of main respiratory diseases in Northern Ireland.
This week, Public Health Northern Ireland began issuing a combined surveillance report on influenza, respiratory syncytial virus (RSV), and COVID-19 to offer a comprehensive view of the epidemiology of these infections within Northern Ireland. The new report, published every Thursday, can be accessed here.
The first chart in this section shows the test positivity rates in Northern Ireland for the main respiratory illnesses — Flu, RSV, and Covid.
The chart indicates that Covid levels have declined from the summer peak and have now stabilised, though they remain significantly higher than the rates of other respiratory viruses.
The chart below presents the weekly count of hospital admissions for the main respiratory illnesses where the infection was contracted in the community, thereby excluding patients who contracted Covid while in hospital. It is important to note that the hospital admissions data for other home nations include patients who contracted infections in the hospital, making them not directly comparable to the data from Northern Ireland.
The chart indicates that throughout much of 2024, the majority of hospital admissions related to respiratory infections were due to Covid. Following the summer peak, Covid admissions have declined and stabilised, yet they remain at a slightly higher level than recorded earlier in the year.
Covid Vaccination Levels in England
The Autumn 2024 Covid booster campaign started last week. Similar to previous booster campaigns, eligibility is restricted to those at the highest risk of hospitalisation and death. Those eligible are older people in care homes, individuals 65 years and older, the immunosuppressed. Eligibility can be checked and boosters booked at this link. In addition, health and care workers will be offered boosters through their employers.
This year's Autumn vaccination campaign is set to end earlier than in previous years, with the majority of vaccinations scheduled to be completed by Friday, 20 December 2024. However, outreach efforts to administer vaccines in underserved communities will continue until 31 January 2025.
The following table shows the cumulative Autumn 2024 coverage for each of the target groups by week.
While significant progress has been achieved in vaccinating target groups aged 65 and older, those clinically at risk under the age of 65 remain less vaccinated.
Worryingly successive booster campaigns have seen lower coverage as highlighted in last weeks report. The Autumn 2023 booster campaign closed with just 65% of those aged 65 to 74 years vaccinated and 76% of the 75 years and older group.
The burden of Covid compared to Flu
Covid is often compared to Flu in terms of the burden that it places on hospitals and individuals, but how
The following chart shows the hospital admission rate for the main respiratory virus in England from 2017 to 2024.
The chart shows that between 2017 to 2020 Flu and RSV follow clear seasonal patterns with hospital admission rates peaking in the winter months. Actions taken to reduce the impact of Covid significantly reduced the seasonal waves of Flu and RSV in 2021 and 2022, but by 2023 the seasonal pattern for hospital admissions for these viruses had returned.
In contrast, Covid hospital admissions occur in waves throughout the year driven by the emergence of new variants and waning immunity. Indeed the recent summer wave saw hospital admissions for Covid approaching the levels seen for a typical Flu winter season. Clearly this represents a higher burden on hospitals than Flu throughout the year and a greater risk to individuals.
A recent study from Denmark aimed to compare the level of hospital and mortality burden for Covid and Flu. The study found that, after adjusting for age and other risk factors, Covid was associated with more than twice as many hospitalisations and deaths compared to Flu.
The following table compares the number of hospital admissions and deaths following hospitalisation for Covid with those for Flu for the main seasons between 2022 to 2024.
The table shows that throughout the period studied there were more hospitalisations and deaths following hospitalisation associated with Covid. The differences were particularly large in the first year after the pandemic. In addition, it was particularly true for Covid that there were not only hospitalisations in the winter, but also in the summer, when in Flu is a rare burden. The study also shows that a hospitalisation for Covid in the winter was more serious than a hospitalisation for flu.
The next table gives the total number of patients and the percentage breakdown by age for admissions and deaths following hospitalisation for Covid and Flu from March 2022 to May 2024.
The table shows that the elderly represent a much higher percentage (75.2%) of hospital admissions for Covid when compared to those for Flu admissions (51.9%). Whilst the patter is not as marked for deaths following hospitalisation (hospital mortality) there is a slightly higher percent of deaths in the elderly from Covid when compared to Flu.
The study concludes that, after adjusting the raw data for age, sex, and vaccination status, Covid has been related to more than twice as many hospitalisations and deaths compared to Flu.
In conclusion
This week more data was made available although, regrettably, there are no indications that the ONS/UKHSA will run a Winter Infection Survey this year.
Although the amount of data currently being published has decreased, the information available for England show that Covid levels are reasonably stable although there are regional differences.
Data from Scotland, Wales, and Northern Ireland indicate that the recent 'summer' wave of Covid-19 had higher infection levels than the 'winter' wave. Levels have decreased since the summer peak, and are relatively stable in Scotland, Wales and Northern Ireland albeit higher than earlier in the year.
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 for England 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 first 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.
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