Omicron dominant Omicron not dominantOmicron detected (low samples) No data

How fast the omicron variant is spreading around the world

The variant detected in November has overtaken delta as the dominant version of the coronavirus

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In the worldwide chart of coronavirus variants below, the red omicron appears at the top right corner in the very end of November. This chart made in collaboration with GISAID represents countries where genomic sequences are publicly released, so some large countries are not included. It takes about a week for laboratories to identify virus variants, so this data is always time-lagged. Using the variant data, the Centers for Disease Control and Prevention estimated that omicron was more than 99 percent of the covid cases in the country last week.

Share of variants in sequenced cases globally
Alpha Beta Delta Gamma Others Omicron
Total
91.7%

The giant blue delta spread began a year ago and covered the world by summer. Omicron has taken over even faster. As of early December, Delta was more than 99 percent of the cases worldwide. In late December Delta was still two-thirds of the cases. Omicron has taken over since then.

The charts below show the mix of coronavirus variants in a selection of countries that currently have high levels of omicron. To capture the latest trends, this map uses three-week periods with the most recent ending last Saturday. In any country, the genomic sequences may be concentrated within a particular outbreak, or may miss some outbreaks, so it is not necessarily representative of the country as a whole.

Countries where omicron is dominant

Sequencing is a process that maps out the genetic code of a particular virus that infected someone so it can be compared to other strains. It is a crucial tool to catch significant changes. If mutations change the virus enough, it becomes a new variant. Variants may have different behaviors that affect the transmissibility of the virus and make it evade the human immune system.

Public and private laboratories submit their sequencing results to the worldwide GISAID Initiative, a nonprofit partnership that broadcasts trends of viral diseases.

[Understanding omicron’s many mutations]

Only a very small sample of coronavirus cases are sequenced, and the process takes about a week. That makes the latest view always a bit out of date compared with daily covid case counts that are setting records as omicron has spread.

Although the level of sequencing varies widely across the world and in the United States, many countries are generating sufficient public genome samples to reveal a trend.

Countries where omicron is also growing

Many countries have not provided sufficient timely samples to the public GISAID data to show the status of omicron’s spread. China and Russia have released very little. In some cases, there may not be technology or resources to do the genomic sequences. In other cases, it may be an issue of transparency.

United States variant trend

Share of variants in sequenced cases globally
Alpha Beta Delta Gamma Others Omicron
USA
94.1%

Sequencing within the United States varies widely. Nationwide, omicron was less than one-quarter of one percent of cases in the three weeks ending Dec. 4, and 37 percent of the genomes sequenced in the three weeks ending Dec. 25. The latest data shows it has taken over almost entirely.

The delta variant was first detected in India in late 2020 and then moved to Europe and the United Kingdom. It hit the United States in July just when cases, hospitalizations and deaths were dwindling. Delta spread faster than the previous variants and was more likely to cause breakthrough cases among vaccinated people. It quickly drove up a spike in cases that peaked in early September. Even as it waned, the low point in late October had six times as many cases as the low point before delta struck. In November, cases nationally began rising with another delta wave before omicron was spreading.

This project will be updated.

Leslie Shapiro and Leo Dominguez contributed to this report.

Dan Keating analyzes data for projects, stories, graphics and interactive online presentations.
Madison Dong is a graphics reporter for The Washington Post.
Youjin Shin works as graphics reporter at The Washington Post. Before joining The Post, she worked as multimedia editor at the Wall Street Journal and a research fellow at the MIT SENSEable city lab.