The Centers for Disease Control and Prevention (CDC) is now tracking another new variant – BA.4.6. The new mutation comes amid the rising spread of the BA.5 subvariant of Omicron, which currently comprises 85.5% of new COVID-19 cases in the U.S.

The new BA.4.6 variant being watched by the CDC currently makes up 4.1% of new cases of the virus, according to the agency. The majority of BA.4.6 cases have been seen in Iowa, Kansas, Missouri, and Nebraska, with cases also confirmed in the mid-Atlantic and Southern region of the U.S., as reported by Fortune .

The new strain of COVID-19 has been detected in 43 other countries, , a site that tracks COVID data, indicated. CDC Chief Data Officer Cyrus Shahpar tweeted on Tuesday that the BA.4.6 variant has been circulating for "several weeks."

While much is still unknown about the BA.4.6 variant, Dr. Eric Topol, founder and director of the Scripps Research Translational Institute, tweeted on Tuesday that the strain of the virus "does not appear to be concerning [compared to] BA.4/5," Fortune reported.

While it is unclear if BA.4.6 is more transmissible or can evade current COVID vaccines or immune response, it does raise alarm with health experts as to how rapidly it mutated from Omicron following the highly contagious BA.5 and BA.4 subvariants.

Typically, subvariants of Omicrons spread quickly, as has been seen with past mutations, and can include symptoms such as fever, chills, cough, shortness of breath or difficulty breathing, fatigue, muscle or body aches, headache, new loss or taste or smell, sore throat, congestion or runny nose, nausea or vomiting, and diarrhea.

Symptoms of COVID-19 typically appear two to 14 days after a person was exposed to the virus and can range from mild to severe.