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Pointless testing flu patients for viral or bacterial illness, finds study


Routinely testing for viral and bacterial pathogens in flu-like illness is meaningless because there are no differences in how patients present, the course of their disease or how severe their illness is, researchers have concluded.

A team of European researchers analysed date from more than 3,000 children and adults taking part in a trial of an antiviral treatment for flu like illness and found no clear clinical differences in those who were found to have a bacterial or viral pathogen.

The only difference in presentation between the two groups was a less prominent congested nose and acute cough in patients where a bacterial pathogen was identified.

Complications and disease course was not related to what was found on swab test results, the team report in the British Journal of General Practice.

It follows other studies which have shown no or only modest effects on use of positive bacterial tests to guide antibiotic treatment in mild respiratory infections, they concluded.

Irrespective of bacterial or viral pathogens identified, most illness was self-limiting lasting for less than 14 days, they noted.

Among participants who were testing osteltamivir in a trial done across 15 countries, 26.3% had no pathogens detected, 60.4% had a viral pathogen, 2.8% a bacterial pathogen and 10.5% had both.

Most patients had a typical flu-like illness with fever, runny nose, and acute cough, together with fatigue and muscle ache.

The results did not change after adjusting for age, treatment group, comorbidities, medication taken, and duration of flu-like illness symptoms at baseline

‘Pathogen identification by laboratory PCR-based testing in primary care patients presenting with flu-like illness was not associated with meaningful differences in presentation or course of disease.

‘A wait-and-see policy in most of these patients with flu-like illness seems the best option and, given the currently available antimicrobial treatments, and outside pandemics such as Covid-19, microbiological testing seems to have limited value,’ they said.

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