Up to a third of ‘corona patients’ in hospital have other ailments

A patient in the covid ward of the Albert Schweitzer hospital in Dordrecht.Statue Arie Kievit

This is apparent from figures from hospitals that have been making the distinction between the two patient groups for some time. Such as the UMC Groningen, which has been taking a corona test with all newly admitted patients for a year and a half. ‘Then someone gives birth and you discover that that person also happens to be positive,’ says medical microbiologist Marjolein Knoester. ‘Very logical. There are now so many people who have the virus that you find this.’

Many hospitals count such positive people as corona patients. Understandable, because the proverbial appendix patient also has to be nursed in isolation after a positive test, in a corona bed. Erasmus MC and Amsterdam UMC also concluded earlier that a third of their ‘corona patients’ are there for another reason.

In order to distinguish such patients from ‘real’ covid patients, the NICE foundation, which registers hospital figures, has been asking hospitals since this week to state the main reason for admission.

old rumor

Such a registration is necessary to keep track of the epidemic, says Susan van den Hof, chief epidemiologist at RIVM. ‘These figures are important for estimating the disease burden, but also for calculating the effectiveness of vaccines, for example.’

The registration gives air to an old rumor that has been circulating for at least a year in circles of people who dismiss the seriousness of corona: that many patients do not go through, but come to the hospital with corona. You get a cotton swab in your nose after a traffic accident, and you count as a corona victim, as MP Wybren van Haga scoffed during debates.

But that’s not true, everyone involved emphasizes. Until recently, patients with other reasons for admission were hardly ever tested in any hospital. And where patients were tested as standard, ‘the finding percentage is very low’, says Knoester. Also in some inventories that individual hospitals carried out, the proportion of positive hospital patients happened to be ‘really very small’, says Van den Hof.

Omikron variant

Recently, however, the problem has been increasing, Knoester emphasizes: ‘Because there are now few covid patients in hospital, the proportion of ‘unexpected positives’ is suddenly very large compared to people with complaints that are consistent with covid-19.’ Still, the vast majority of patients who come to the hospital for an operation or admission test negative.

The omikron variant in particular changes this situation. Not only do more people have the variant among the members, they also notice it less. As a result, the number of people with ‘accidental’ corona among the members has increased. The infection rate is particularly high among young people: this may contribute to the fact that relatively many people under the age of 30 appear in the corona registrations in recent weeks.

Most of the patients are still present in intensive care for corona complaints. According to the NICE foundation, more than 90 percent of infected IC patients have been admitted because of covid-related symptoms.


It is often quite difficult to make the distinction between through or with corona in practice, says doctor-microbiologist Bert Mulder (Canisius Wilhelmina Hospital). ‘I saw a few patients with pyelonephritis – pelvic inflammatory disease – and a positive test for omikron. If you then look in the literature, you will soon find studies that suggest that pyelonephritis can be a complication of Covid.’ Only after some time did Mulder realize that the corona infection was probably just a coincidence.

In addition, there are many patients with an underlying condition such as cardiovascular disease or diabetes, which is ‘disrupted’ by a corona infection, says Van den Hof. Hard to say whether these are covid patients, or whether the corona is an afterthought. That is why NICE distinguishes on its form for hospitals between positively tested patients in whom corona symptoms are the main reason, one of the reasons, or no reason for admission.

The standard corona tests in hospitals also have an additional disadvantage. Often people who come to the hospital for a procedure that can also wait are sent home. This in turn leads to more delayed care and suffering for patients. ‘It is quite intense if such an operation is postponed’, Knoester points out. “For many people, the operation is much more important.”

Because of / with corona elsewhere


In Danish hospitals, with the emergence of omikron, the number of people who tested positive for another reason doubled: from about 15 percent in the delta period to about 30 percent now. This increase in the proportion of patients ‘with’ corona mainly occurs among the somewhat younger people, the group where omikron also spreads faster. Of the positively tested people over 60, covid-19 is the main reason for admission in 80 percent.


In England, doctors are asked to determine ‘to the best of their knowledge’ who is ‘by’ and who is in hospital ‘with’ corona. Despite this somewhat vague distinction, an upward trend is also visible in the English figures. In September, the corona infection was a by-catch in about one in four positive hospital patients. In the meantime, 40 to even 50 percent of all positively tested patients are initially in hospital for another reason.


In France, too, an increasing proportion of corona patients in hospital are admitted there for a different reason. This is currently the case in 26 percent of the cases. In admitted twenties this even concerns half of the new patients. The infection rate is high in France, about 300 thousand French people tested positive every day last week.


In Spanish hospitals, 25 to 40 percent of the infected persons admitted are hospitalized for another condition, according to data published by the newspaper. El Pais has requested.


Unlike many European countries, the United States has higher hospital numbers than in previous corona waves. Some of these patients also appear to have corona ‘coincidentally’. In New York state, where 10,000 patients who have tested positive have now been admitted, 44 percent are in hospital for a reason other than Covid-19.