The World Health Organisation (WHO) has strongly advised against antibody treatments for Covid-19 patients, saying antibody drugs sotrovimab and casirivimab-imdevimab are not working on new variants like Omicron.

These drugs work by binding to the SARS-CoV-2 spike protein, neutralising the virus’s ability to infect cells.

A WHO Guideline Development Group of international experts in the British Medical Journal (BMJ) BMJ said that almost all well-informed patients would not choose to receive sotrovimab or casirivimab-imdevimab.

The strong recommendation replaces previous conditional recommendations for their use and is based on emerging evidence from laboratory studies that these drugs are not likely to work against currently circulating variants, such as Omicron.

In the same update, the WHO made a conditional recommendation for the use of the antiviral drug remdesivir in patients with severe Covid-19, and a conditional recommendation against its use in patients with critical Covid-19.

These recommendations are based on results from five randomised trials involving 7,643 patients, showing 13 fewer deaths per 1,000 patients with severe Covid-19 taking remdesivir, but 34 more deaths per 1,000 patients with critical Covid-19 taking the drug.

“These new trial data provided sufficiently trustworthy evidence to demonstrate benefits in patients with severe Covid-19, but not critical Covid-19. The panel considered the benefits of remdesivir to be modest and of moderate certainty for key outcomes such as mortality and mechanical ventilation, resulting in a conditional recommendation,” said the update.

The WHO also advised that three drugs used to treat arthritis – the IL-6 receptor blockers tocilizumab or sarilumab and the JAK inhibitor baricitinib – may now be combined, in addition to corticosteroids, in patients with severe or critical Covid-19.

This advice is based on new high-certainty trial evidence confirming a survival benefit for baricitinib with little or no serious adverse events when given in combination with corticosteroids and IL-6 receptor blockers.

However, the panel acknowledged some cost and resource implications associated with these drugs, which, they say, could exacerbate health inequities.

Previously, the WHO has made a strong recommendation for use of nirmatrelvir and ritonavir, and a conditional recommendation for molnupiravir for high-risk patients with non-severe covid-19. WHO advises against the use of ivermectin and hydroxychloroquine in patients with covid-19 regardless of disease severity.