Thread by @ZdenekVrozina

Hidden driver of mortality. A new study makes an uncomfortable point very clear. Respiratory viruses are probably involved in far more deaths than we usually recognize in day-to-day clinical practice or in official cause-of-death statistics🧵

Across 4 influenza seasons, a respiratory virus was found post mortem in 36.4% of deceased people. Influenza alone was present in 11.0%. It was not just flu either - rhinoviruses, common human coronaviruses, and RSV were also frequent.

The most striking part is how much was missed before death. Among people with influenza detected post mortem, only 17% had been diagnosed with influenza while alive.

That matters because what gets recorded as cardiac death, respiratory failure, or general decline may, in many cases, have had a hidden viral trigger helping push a frail patient over the edge.

The study does not claim every virus detected was the direct cause of death - but it strongly suggests we are overlooking a major part of the story.

These viruses are not harmless background noise. They can worsen an already fragile situation, destabilize chronic illness, and become part of fatal outcomes even when they never make it into the headline diagnosis.

The signal was especially strong in long-term care facilities, where any respiratory virus was found in 52.3% of deceased residents!

That is exactly where transmission is easier, patients are more vulnerable, and missed infections can carry the heaviest consequences.

So ignoring such a high prevalence would be a mistake. These infections are being underdiagnosed in life and undercounted in death.

The practical takeaway is simple.
Test more, think of viral etiologies more often, and stop assuming that if a patient looks cardiac, pulmonary, or just frail, infection is no longer central to what is happening.

And this study comes from the pre-COVID era. Since then, SARS-CoV-2 arrived. More severe, poorly tested, devastating in care homes, and far too often met with delayed, limited, or badly implemented antiviral access.

If we were already underestimating how flu and other respiratory viruses contribute to fatal decline, COVID only made that blind spot bigger. We need better testing, earlier recognition, and much better treatment access for the people at highest risk.

Trobajo-Sanmartín at al., Prevalence of influenza and other respiratory viral infections in deceased persons: a population-based observational study over four influenza seasons. clinicalmicrobiologyandinfection.org/article/S1198-…