Covid Situation Report: Jan 18, 2023
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 is the tenth of the weekly Covid Situation Reports I plan to publish over the Winter 2023 / Spring 2024 season. Each report provides an overview of the present Covid status in England and its regions using a standard set of interactive charts. For those who want a bit more detail I will do a deeper dive on topics of interest each week. This week I take a detailed look at the latest data from the Winter Infection Survey for England and Scotland.
Summary
The Winter Infection Survey estimates that on January 10 there were 1 in 43 people infected with Covid in England and 1 in 56 people infected with Covid in Scotland.
In the past two weeks Covid prevalence has decreasing in England and Scotland across all age groups but is still higher in younger adults.
Last year we also had a decline in prevalence immediately after Christmas but there was an increase in late January that continued in to February. Consequently, it would still be a good idea to test if you have symptoms and take appropriate precautions if you are meeting vulnerable people.
Positivity rates and weekly hospital admissions for Covid and RSV decreased last week but Flu admissions increased slightly this week.
The latest daily Covid hospital admissions and occupied beds data decreased in the past week consistent with the prevalence and weekly hospitalisation trends.
The JN.1 ‘Juno’ variant is now dominant in the UK making up 72% of the sequenced variants, and has driven the recent wave of infections.
Finally, a reminder that although the main booster program is closed in England, UKHSA advised that you may be able to get vaccinated at a walk-in site which can be found at the following link until the program closes on January 31, 2024
Winter Covid Infection Study
This week UKHSA published the latest results from the ONS Winter Infection Study.
Although based on the ‘gold standard’ Coronavirus Infection Survey (CIS) that stopped in March 2023 the Winter Infection Survey differs in several ways. Consequently, statistics from the two studies cannot be compared directly. However, the Winter Infection Study is still based on testing a representative sample of the population each week so the results are not impacted by any change to testing numbers.
In this weeks report UKSHA published the estimated prevalence of Covid for England and Scotland, together with the prevalence by region and age group. It is important to note that prevalence is different from the positivity rate.
Prevalence is the estimated proportion, expressed as a percentage, of all individuals within the reported group who are infected with the the Covid virus at a given point in time. Importantly, prevalence adjusts for the age profile of the sample of people responding to the survey being different from the age profile of the general population. It is different from the positivity rate which is simply the percent of people testing positive and takes no account of the age profile of those tested.
The key finding from this weeks Winter Infection Survey is that the prevalence of Covid in England and Scotland continued to decrease in the 2 weeks leading up to 10 January 2024.
The following chart shows the trend in prevalence of Covid in England from Nov 14, 2023 to Jan 10, 2024.
The prevalence for Covid in England continues to decrease and on Jan 10, 2024 was 2.3% with an estimated 1 in 43 people infected. However, there are signs that prevalence is plateauing. This is quite a bit lower than last week, when an estimated 1 in 31 people were infected but is higher than at the start of the survey when prevalence was 1.4%. Although not directly comparable, prevalence in England for the week ending Jan 10, 2023 was 2.6%.
The prevalence for Covid in Scotland also decreased in the past 3 weeks from the peak of 3.7% on Dec 20 to 1.8% on Jan 10. An estimated 1 in 56 people are now infected which is much lower that the 1 in 36 people reported last week
The following chart shows the prevalence by age group for England and Scotland over the past five weeks with the orange bars showing the latest week
Across England and Scotland prevalence has declined in the past two weeks across all age groups but remains highest for individuals aged between 18 to 44 years compared to those aged 65 years and over. Once again, prevalence for those over 75 years old is declining at a slower rate.
The next chart shows the prevalence by region over the past five weeks with the orange bars once again showing the latest week.
The prevalence has decreased in every English region over the past 2 weeks and particularly in the London and South East regions. However, prevalence remains high in the South West.
Just a reminder that last year we also had a decline in prevalence after Christmas probably due to reduced mixing over that period. However, increased mixing from returning to work after the holiday break led to an increase in late January that continued in to February. Consequently, it would still be a good idea to test if you have symptoms and take appropriate precautions if you are meeting vulnerable people.
Status of main respiratory diseases in England
The following chart shows the positivity rates for the main respiratory diseases in England which are Flu, Covid, RSV and Rhinovirus.
Positivity rates for the main respiratory diseases fell except for Flu which remained unchanged. This data is consistent with the fall in Covid prevalence reported in the Winter Infection Survey.
The following chart shows hospital admissions per 100,000 people in England for the main respiratory diseases.
Whilst Covid had a week on week fall in hospital admission rates (down by 6%), Flu admissions increased slightly (up by 3%).
The concurrent waves of Covid and Flu are much less than last year so the pressure on the hospital system is greatly reduced. For a more detailed review of the impact on the Emergency Services see my NHS England Status Update for Dec 2023 by clicking on the following button.
Covid hospital admissions and bed occupancy
Turning now to look in more detail at the latest daily data on Covid in hospitals in England. The following dashboard of key Covid metrics for hospitals in England saw daily hospital admissions and beds occupied by patients with Covid decreasing significantly this week. However, the number of mechanically ventilated beds occupied had a week on week increase although from relatively low levels.
Unlike last weeks report, this is consistent with the weekly admissions data which also showed a decrease in hospital admissions.
The regional picture shows that all regions had week on week decreases for hospital admissions. The following interactive dashboard gives the Covid hospital admissions per 100,000 by region.
All regions had significant reductions apart from the North West which only had a small reduction.
Covid Variants
The coronavirus that causes Covid continues to mutate and spread. The following chart shows the percent of the most common variants found in the UK since April 2023.
Recently a strain called JN.1, commonly called ‘Juno’, has moved swiftly to become the most widely circulating variant in the UK currently making up more than 70% of cases in early January. This is the first time since March 2023 that we have has a single variant being so dominant.
The JN.1 Covid variant is a descendant of the BA.2.86 Omicron variant. It is more infectious than the previous BA.2.86 variant and is undoubtedly the cause of the recent increase in cases.
An initial assessment from the WHO from December 2023 concluded that:
With the limited data at this stage, the available evidence on JN.1 does not suggest additional public health risks relative to the other currently circulating Omicron descendent lineages
Whilst it is too early to be certain it seems likely that it has a lower infection to hospitalisation rate (IHR) and, due to the existing immune protection in large parts of the UK’s population, most JN.1 cases will be mild. However, this still represents a threat to the clinically vulnerable and, although vaccination reduces the impact, the risk of ‘Long Covid’.
In conclusion
This weeks Winter Infection Survey shows that Covid prevalence continues to fall across England and Scotland.
Unlike the last report, the data on daily and weekly Covid hospital admissions data are consistent and both are falling as we would expect from reduced prevalence.
JN.1 ‘Juno’ is the dominant variant in the UK and has driven the recent wave of infections.
As always, if you have any comments on this Covid Situation Report or have suggestions for topics to cover then please post a message below.
Could it be that flu infection dampens a covid infection wave. Like last year it seems when Flu peaks greater than covid infection the Covid wave increase is terminated at the decline commences. Could it be that flu takes out of the population people (whose behaviour makes then susceptible to respiratory infection ) who would have gone onto contracting covid and infecting others; from their flu sick bed they can't catch covid and infect others. Maybe its the difference in the infection to symptom timespan between flu and covid that is the factor, and why covid waves in winter/flu season are dampened more than the covid waves in summer when flu is not so prevalent. Also flu symptoms make take potential asymptomatic covid infectors out of the population which would not happen in a covid wave outside of the flu season?
Great summary as usual!