Covid patients shouldn’t be given antibiotics, scientists have warned, except in rare circumstances where a secondary bacterial infection is present. 

The warning comes after a study led by the University of Glasgow found that antibiotic use was very high in hospitalised Covid-19 patients in the UK during the first wave, despite there rarely being a confirmed bacterial infection.

“Covid-19 is a viral infection. Antibiotics are ineffective against viral infections, unless a bacterial co-infection is present,” lead author Dr Antonia Ho, from the MRC-University of Glasgow Centre for Virus Research, tells HuffPost UK.

Not only do antibiotics not work for treating a virus like Covid, but using them unnecessarily can predispose patients to side effects in the future and, perhaps more worryingly, can drive antibiotic resistance.

It’s estimated that at least 5,000 deaths are caused every year in England because antibiotics no longer work for some infections – and this figure is set to rise.

What did the study find?

Overall, 85% of Covid-19 patients received one or more antibiotics during their hospital admission in the first wave, with the highest use in critical care, while 37% of patients were prescribed antibiotics prior to admission.

There was high use of broad-spectrum antibiotics – those active against a very wide range of bacteria. But confirmed bacterial infections – which actually require antibiotics – were uncommon in people with Covid-19, especially when first admitted to hospital, the study found.

Most of the bacteria identified represented secondary infections which began more than 48 hours from admission into hospital. 

So should antibiotics be ruled out completely? 

Not quite. Although co-infections were rarely observed during the first wave of the pandemic, there remains a need to monitor hospitalised patients in light of increased use of steroids and other Covid-19 treatments, which may increase susceptibility to bacterial infection, researchers said.

However, they stressed that over-prescription of antibiotics, particularly broad-spectrum antibiotics, in the majority of hospitalised patients with Covid-19 has raised “significant concern” about the impact on antibiotic resistance globally.

“This study demonstrates the very high antibiotic use we see in hospitalised Covid-19 patients may not be necessary, indeed it may contribute to antimicrobial resistance,” says Dr Ho. “While some Covid-19 patients will require antibiotics, mostly for secondary infections which develop after admission to hospital, our data shows that not all Covid-19 patients should be prescribed antibiotics.”

It’s “unsurprising” that doctors offered antibiotics to patients during the first wave, she added, “given the unprecedented challenges posed by the pandemic, particularly during its early stages when admitted patients were very sick, effective treatments were limited, and the role of possible co-infections unknown”. However, “antimicrobial resistance remains one of the biggest public health challenges of our time”.

Anyone offered antibiotics to treat symptoms of Covid-19 should ask their healthcare professional if they’re concerned about a bacterial co-infection, says Dr Ho. If the answer’s no, it’s worth pushing back. 

Professor Calum Semple, co-lead author of the study, adds: “We only have safe surgery and medical cures for many life threatening conditions because antibiotics were discovered and mostly still work. 

“Overuse of antibiotics needs to be avoided to prevent emergence of resistance. When the current threat from Covid-19 subsides, the problem of antimicrobial resistance will remain a threat.”