Instead, irremediable bacterial lung infections – admittedly facilitated by COVID-19 – ultimately killed many seriously ill corona patients. American researchers say so.
Seriously ill corona patients who were put on a ventilator in the ICU were remarkably often confronted with a bacterial lung infection. And in the end, that infection, if it could not be cured, was in many cases also the reason that these corona patients died. In fact, bacterial infections among seriously ill corona patients may have claimed many more lives than the corona virus itself. American researchers come to this conclusion Journal of Clinical Investigation.
They are based on an analysis of 585 patients who were put on a ventilator in the ICU because of serious breathing problems. 190 of these patients had COVID-19. During the stay of these patients in the ICU, a wealth of information was naturally collected about their health status and how it changed over time (for the better or for the worse). The researchers left a machine learningalgorithm on all that data to get a better picture of the disease course of the patients and to get a grip on what had been decisive for a good or wrong outcome.
Secondary bacterial infection
First of all, the study shows that seriously ill corona patients who are on a ventilator are remarkably susceptible to a ‘secondary bacterial lung infection’. “Any patient on a ventilator is at risk of secondary bacterial pneumonia or ventilator-induced pneumonia,” said lead researcher Benjamin Singer. Scientias.nl. “This can arise during mechanical ventilation of the patient, because the methods that the lungs normally use to protect themselves (such as coughing) cannot be used and the breathing tube also gives bacteria fairly easy access to the lungs. What we saw (during the study, ed.) was that patients with SARS-CoV-2-induced pneumonia were twice as likely to develop secondary bacterial pneumonia than patients who had developed pneumonia due to other causes and were on the ventilators, but were just as sick as these corona patients.”
Mortality from secondary bacterial infections
That patients who have been struck down by a virus sometimes die from a secondary bacterial infection is nothing new in itself, Singer emphasizes. “Secondary bacterial pneumonia has been recognized as a potential cause of death among patients with viral pneumonia since the 1918 flu pandemic. But we were surprised at the prevalence of ventilator-induced pneumonia among patients with COVID-19 – more than twice as common as among ICU patients similarly ill due to other pathogens. In addition, we were also surprised to see how strong the association was between an incurable secondary bacterial infection and death.”
COVID-19 vs bacterial infections
In other words: in many cases, an irremediable secondary bacterial infection was found to be the cause of the death of corona patients in the ICU. “Those who were cured of their secondary pneumonia had a higher chance of survival, while those whose secondary pneumonia could not be cleared had a higher chance of dying.” And in the end, more corona patients may have died in the ICU from an untreatable secondary bacterial infection than from corona itself. “Our data suggests that mortality due to the virus was relatively low, but that other things that happened during the ICU stay, such as the onset of secondary bacterial pneumonia, compensated for that.”
Indirect victim of COVID-19
It should of course be noted that although these seriously ill corona patients did not die from corona, the virus did indirectly kill them. After all, without corona they would not have ended up in ICU and put on a ventilator and therefore they would not have developed secondary pneumonia. “That’s important,” Singer agrees. “These fatal secondary pneumonias all arose because patients were critically ill from COVID-19.” The study therefore does not detract from the mortality figures from corona or the danger of a corona infection. It only provides more insight into the impact SARS-CoV-2 had directly and indirectly on critically ill patients.
The study counts on this in passing also dismisses the idea that many seriously ill COVID-19 patients spent a long time in the ICU or even died due to a cytokine storm. “The term ‘cytokine storm’ refers to overwhelming inflammation that leads to the failure of organs, such as the lungs, kidneys and brain,” explains Singer. “If the cytokine storm was the cause of the long-term stay of corona patients (in ICU, ed.), you would expect that we would often see that several organs gradually fail in our patients. But we did not see that (…) Instead, we saw that patients with COVID-19 tend to suffer from long-term respiratory problems and therefore spend a long time in the ICU.” And that is ultimately why they are so susceptible to a secondary bacterial infection, the researchers argue. “The relatively long stay of corona patients (in ICU, ed.) is mainly due to long-term respiratory problems, which entails a greater risk of ventilator-associated pneumonia.”
Not the cytokine storm, but an irremediable secondary bacterial infection therefore seems to be an important driving force behind the death of seriously ill corona patients who have been admitted to the ICU. And with that tentative conclusion in his pocket, Singer argues for further research. Including the most effective ways to prevent, diagnose and treat a ventilator-induced infection. Incidentally, this not only benefits seriously ill corona patients, but also people who end up in ICU for other reasons and are temporarily dependent on ventilators.