Research suggests hospitalisation risk lower for Omicron

Data from a pre-print study in the UK suggests that Omicron cases have an average a 15–20% reduced risk of any hospitalisation, and an approximately 40–45% reduced risk of a hospitalisation resulting in a stay of one or more nights compared to Delta.
 
The study, from Imperial College London, also found that the risk of hospitalisation for people who are double-vaccinated is similar for Omicron and Delta strains of COVID, with the risk of hospitalisation in vaccinated people remaining significantly lower than for unvaccinated people. 
 
According to the authors, their data suggests people who have received at least two doses of vaccine remain substantially protected against hospitalisation, even if protection against infection has been largely lost against the Omicron variant.
 
The researchers stress, however, that these estimated reductions in severity must be balanced against the increased risk of infection with Omicron, with greater infection numbers potentially still leading to large numbers of hospitalisations.
 
‘Given the high transmissibility of the Omicron virus, there remains the potential for health services to face increasing demand if Omicron cases continue to grow at the rate that has been seen in recent weeks,’ Professor Neil Ferguson Director, of Imperial College London’s MRC Centre for Global Infectious Disease Analysis and Jameel Institute, said.
 
Australia’s hospitalisation rates – which many experts suggest should be the real measure of the country’s ongoing Omicron-driven COVID wave – have been increasing along with case numbers, especially in New South Wales and Victoria.
 
The authors say it is essential to place the severity of Omicron in the context of reinfection risk in countries, like England and South Africa, where a large proportion of the population may have already been infected. This could also be increasingly relevant in Australia, with the country now recording tens of thousands of new cases every day.
 
‘Our analysis shows evidence of a moderate reduction in the risk of hospitalisation associated with the Omicron variant compared with the Delta variant; however, this appears to be offset by the reduced efficacy of vaccines against infection with the Omicron variant,’ Professor Neil Ferguson from Imperial College London said.
 
‘Given the high transmissibility of the Omicron virus, there remains the potential for health services to face increasing demand if Omicron cases continue to grow at the rate that has been seen in recent weeks [in the UK].’
 
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