Estimates suggest people who test positive for the Omicron variant of the coronavirus are 15% less likely to attend hospital, and 40% less likely to be hospitalised for a night or more, compared to Delta.
Researchers from Imperial College London (ICL) stress that these estimated reductions in severity must be balanced against the larger risk of infection with Omicron, due to the reduction in the protection provided by both vaccination and natural infection.
For example, at a population level, large numbers of infections could still lead to large numbers of hospitalisations. They say the estimates provided in this paper will assist in refining mathematical models of potential healthcare demand associated with the unfolding Omicron wave in Europe.
Professor Neil FergusonDirector of Imperial’s MRC Centre for Global Infectious Disease Analysis and Jameel Institute 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.”
Yesterday, 281 people in Bradford tested positive for Covid-19, bringing the total number of people who have had Covid-19 in the District to 101, 607. As of Friday, 17 December, there were 19 confirmed cases of the Omicron variant, with 203 more expected cases. Updated numbers are released tomorrow.
The estimates suggest that Omicron cases have, on 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.
Reinfection is associated with approximately a 50-60% reduction in hospitalisation risk compared with primary infections.
The new report from the ICL Covid-19 response team estimates hospitalisation risk for Omicron cases in England. The data set included 56,000 cases of Omicron and 269,000 cases of Delta.
In the study, hospital attendance was defined as any record of attendance at a hospital by a confirmed case in the 14 days following their positive PCR test, up to and including the day of attendance.
A secondary analysis examined the subset of attendances with a length of stay of one or more days.
The researchers caution that insufficient time has passed for enough data to have accumulated for severity to be judged for more severe outcomes such as intensive care unit admission or death.
Professor Azra Ghani, Associate Director of the MRC Centre for Global Infectious Disease Analysis, said: “Whilst the reduced risk of hospitalisation with the Omicron variant is reassuring, the risk of infection remains extremely high. With the addition of the booster dose, vaccines continue to offer the best protection against infection and hospitalisation.”