Omicron causing 60% of Amsterdam Covid cases; OMT studying hospitalization rate

Omicron became the dominant variant of the coronavirus in Amsterdam on Tuesday, the Argos consortium reported. The variant seems to cause less severe symptoms than the Delta variant, but two experts from the Outbreak Management Team are still concerned about extra pressure on hospitals.

The Argos consortium, a collaboration between health service GGD Amsterdam and Amsterdam University Medical Center, tested a random sample of 106 coronavirus cases. 63 of them involved the Omicron variant. That means that the new variant increased from 4 percent to 59 percent of cases in Amsterdam in nine days.

A total of 63/106 (59%) randomly selected SARS-CoV-2 positive samples, collected on the 21st Dec 2021 at @GGDAmsterdam testing facilities, were positive for the Omicron variant based on the spike 371L/373P assay. Great effort by teams at @amsterdamumc & @inBiome. pic.twitter.com/GcIYXMSs2K

— ARGOSconsortium (@ARGOSamsterdam) December 22, 2021

An ongoing study by the Imperial College in the United Kingdom showed that people are about 45 percent less likely to be hospitalized with the Omicron variant than with the Delta variant. That is hopeful, but not yet a reason for celebration, Outbreak Management Team members Alma Tostmann, and Marc Bonten said to NOS.

"What you can conclude from this is that this variant is a lot less sickening than the Delta variant. In that respect, it is good news," said epidemiologist Alma Tostmann. "We already saw that a bit with data from South Africa." But that does not mean that the new variant will lead to fewer hospitalizations because Omicron is more contagious and spreads very fast. "The bad news you have to face is that with high numbers of infections, you will still end up with a lot of hospitalizations."

Physician microbiologist Bonten also told NOS that he is partly positive, but with a caveat because of the higher contagiousness. "You have to compare these results with the number of people who become infected. If that is twice as much as with the Delta variant, you have just as many people who end up in hospital."

The OMT will discuss the new data in a meeting later on Thursday, Bonten said. "We can use these numbers in the models, and I assume that we will immediately see the latest calculations at the OMT meeting." The models inform the OMT's advice on the coronavirus policy.