Thread by @IHME_UW

We just updated our COVID-19 model covid19.healthdata.org with the latest data & updated our policy briefings healthdata.org/covid/updates for over 200+ world locations.

We've got good news to confirm about Omicron.🧵

The good news:

As expected, the transmission intensity of Omicron is so great that it sweeps through populations in a very short period of time and then starts to decline.

The numbers of infections and numbers of reported cases really seem alarming to most people because they are much higher than what we’ve seen in other waves in the pandemic. But the health effects of #omicron, and the effects on death, are very muted.

The reason for this is because the severity of Omicron is quite dramatically lower than Delta. There are 3 parts to this reduction in severity:

1. The fraction of cases that have no symptoms at all. For Delta, systematic review suggested about 40% had no symptoms... (continued)

With Omicron, as best as we can make out from a variety of data sources, 80-90% have no symptoms at all. So of these millions of infections that are happening all over the world, there are a huge number with no symptoms at all.

2. Among those people who have symptoms, the number who end up in the hospital due to Omicron turns out to be half as much as what it was for Delta.

3. For those who end up hospitalized due to Omicron, the number who go on to require intubation or mechanical ventilation, or the fraction who go on to die, looks like it’s down 80-90%.

In short:

A big increase in asymptomatics, half reduction of those who go to hospital among those who are symptomatic, and a five-fold or ten-fold reduction of those dying from COVID-19 while in hospital, you get the observation that Omicron is 90-99% less severe than Delta.