The U.S. has lowered its travel advisory for South Korea by a notch to the second highest level.

The Centers for Disease Control and Prevention(CDC) removed about 90 countries, including South Korea, from its "Do Not Travel" list, the highest in its four-tier travel alert system.

The move comes about two months after the CDC raised its travel advisory for South Korea by a notch to the highest Level Four, citing "very high" levels of COVID-19.

Per the CDC’s metrics, countries are considered to have "very high" COVID-19 levels when they report more than 500 new cases per 100-thousand people over the past 28 days.

However, the CDC lowered its advisory for South Korea back to Level Three, under which travelers who are not fully vaccinated are advised to "avoid travel" to the designated countries.

The latest update is reportedly part of revisions to the CDC's travel advisory system.