Norwegian study confirms that Omicron gives a lower risk of hospitalization

Preliminary data on length of stay and risk of needing intensive care suggest that Omicron gives milder disease also for patients who are hospitalized, according to the new study done by researchers at the Norwegian Institute of Public Health (NIPH).

The findings should be interpreted with some caution as the study is based on a small group of hospitalized patients, the NIPH notes.

“These findings contribute to increased knowledge and show that there is a lower risk of serious disease among those infected with Omicron rather than the Delta variant. This is in line with results presented in reports from a number of other countries,” said Department Director Line Vold.

Somewhat lower effect of vaccines

The study supports that being vaccinated further lowers the risk of hospitalization. But the researchers also found that people who are only vaccinated with one or two doses, have a slightly lower reduction of risk when infected by Omicron compared to the Delta virus.

For the triple vaccinated, the numbers were the same for Omicron and Delta: The risk of hospitalization was reduced by 86-88 per cent compared to the unvaccinated.

Burden on hospitals

“The lower risk of hospitalization associated with Omicron doesn’t necessarily mean that we expect a reduction in the burden on the hospital sector. We also need to consider the fact that Omicron is spreading at a much higher rate than Delta, combined with the fact that the effect of vaccines seem to be lower against Omicron,” Vold explains.

“The results show that it’s important that people continue to accept the offers of vaccination, whether it’s their first, second or third dose,” she adds.

The study was done between December 6 last year and January 9 this year. It is based on about 39 500 cases of Omicron, of which 91 were hospitalized, and nearly 51 500 cases of Delta, of which 552 were hospitalized.

Translated by: Ida Irene Bergstrøm