COVID-19: A closer look at hospitalisation, ventilation data

The tables below show how the changes in the number of daily new confirmed COVID-19 cases, hospitalisations and the number of ventilated Covid patients in 2021 and 2020. These are all 7-day averages to avoid distortions caused by comparing weekdays with weekend days when authorities do not publish statistics, and the aggregate data released on Mondays have to be distributed for three days with a certain methodology.

In the top chart we compared the figures of 16 December to one, two, three, and four weeks earlier. The second chart shows the week-on-week changes.

The 7-day average of the number of new cases shows a 26.4% week-on-week decline, and the figure is 46% lower than two weeks ago. The number of Covid patients in hospital also went down by nearly 13% w/w, and the 7-w average number of ventilated Covid patients shows a 6.2% w/w drop. Balázs Pártos has taken an even closer look at the trends, and his findings are detailed below with the help of additional graphs.

Note that the ventilation data are adjusted by Portfolio's methodology, i.e. the official daily figures have been adjusted 40% higher since 28 Nov, not just for the sake of comparability but also to reflect reality more accurately. It is because the Coronavirus Task Force unexpectedly started to request hospitals to submit both invasive and noninvasive ventilation statistics, but it publishes only the number of Covid patients who are intubated (invasive ventilation) which resulted in a cc. 40% drop in the official number of ventilated Covid patients.

The left-hand chart of the first pair below shows that there are more deaths per a day spent in hospital than a year ago. Although the ratio has been dropping for some reason, and if this actually reflects reality it is definitely a favourable development. Yet, the ratio is still about 50% higher than last year (3.0% vs. 2.2%).

Should we hope that the ratio will keep dropping? We should but whether this hope will be fulfilled is highly questionable, given how ventilation numbers are changing (see more below).

The right-hand chart shows that the share of deaths to days spent in ICUs is exactly the same as last year.

The left-hand chart of the pair below shows that a higher percentage of Covid patients hospitalised are in severe condition (in ICUs or on ventilator). One way to look at this is that the Delta variant causes more severe disease (true). Another possible interpretation is that vaccinated people that need to be hospitalised are in a really bad shape (true). Thirdly, it is also true that there are far fewer people in hospital than how many should be there. It is unclear how strongly these factors are at play, but it may not even matter that much. The ratio is 25% higher than last year (10% vs. 12.5%).

The right-hand graph shows that there are slightly fewer deaths per confirmed cases than a year ago. “Fewer” is the good news; “slightly” is the bad news. There should be a lot fewer deaths, considering that millions of people are vaccinated against SARS-CoV-2.

Note, however, that only slightly more than three million people, less than third of the population, have received three doses of COVID-19 vaccines, while studies showed that four, five or six months after the second jab even two doses lose some effectiveness against infection. Not to mention the extremely rapid spread of the Omicron variant, against which two doses are even less effective, according to studies.

The difference between the current situation and the one a year ago could be this small because local authorities are testing only those that show severe symptoms. And, of course, some of those that they want to declare recovered. The difference should be two or three times bigger.

The left-hand graph below shows that there are more confirmed COVID-19 cases than a year ago, and also more deaths.

The right-hand graph shows that the time Covid patients spend in hospital is shorter than last year, but those who are admitted to ICUs spend more time there.

The chart on the left shows a higher number of cases, but fewer days spent in hospital. Should we celebrate?

Oh, no, there’s the chart on the right, showing more days spent in ICUs than last year. And more people died too. But let’s not repeat ourselves here.

Another pair of graphs. The one of the left shows that the peak in hospitalisations has been reached. For now, at least. If the direction is maintained, the situation will not be much worse than a year ago, only more protracted. The number of ventilated Covid patients is also coming down. Again, the direction is good, but…

On the right you can see that the number of days spent in hospital per registered cases and the number of days spent in ICUs are both going up. The latter may be understandable, as those admitted spent quite some time there. But there is a rise in hospitalisations too, which suggests not only that there are “too few” people with coronavirus infection in hospitals, but also that as we go forward in time their share will be lower than it should be.

The pair below show the same graph only on different scales. The on ventilator / in hospital ratio does not look good (see note on the tweak to the calculation of ventilated patients above). What was already dropping at this time of year in 2020 is now going up.

If the outcome will be fewer deaths than last year, it will be extremely odd, consider that the same share of Covid patients in ICUs die than last year on an accumulated basis. So, if you find that there are fewer Covid deaths in the last two weeks of the year than in the base period, then it will be either a miracle or some serious data distortion.

Cover photo: MTI/Attila Balázs