The agency's Nowcast data tracker, which displays COVID-19 estimates and projections for two-week periods, projects the KP.3.1.1 variant is accounting for 36.8% of positive infections, followed by KP.3 at 16.8% in the two-week stretch starting Aug. 4.

"The KP.3.1.1 variant is very similar to other circulating variants in the United States. All current lineages are descendants of JN.1, which emerged in late 2023," Rosa Norman, a spokesperson at the CDC, previously told USA TODAY.

"At this time, we anticipate that COVID-19 treatments and vaccines will continue to work against all circulating variants,' she said. "CDC will continue to monitor the severity of variants and will monitor vaccine effectiveness."

Previously, the KP.3.1.1 variant made up 22.8% of cases for the two-week period ending on Aug. 3 and KP.3 accounted for 21.0%. According to the data, KP.3.1.1 rose 14% and KP.3 decreased 4.2% from Aug. 3 in projected positive infections.

Here is what you need to know about the KP.3.1.1 variant.

See latest data: CDC says COVID is at 'very high' activity levels in some US states

How are KP.3 and KP.3.1.1 variants similar?

According to the CDC's Nowcast data, the KP.3.1.1 COVID-19 variant was the most prevalent strain at the national, regional, and state levels for the week ending Aug. 17.

Norman previously explained that KP.3.1.1 has one change in spike protein.

JN.1, a variant that has been circulating since December 2023, only saw a single change in spike, unlike the KP.3 variant, which is a sub-lineage of the JN.1, Dave Daigle, a spokesperson at the CDC, previously told USA TODAY.

"KP.3.1.1 has one change in the spike protein in comparison to KP.3," Norman said.

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COVID-19 Current Wastewater Viral Activity Levels Map

CDC data shows that over half of the United States have reported "very high" levels of COVID-19 activity.

Using wastewater or sewage, the CDC tests the water to see if there are any traces of an infectious disease within a community, the government agency says.

Data collected on Aug. 9 by the CDC showed that 27 states have reported "very high" levels of wastewater viral activity nationwide.

Here is a map of the states and territories that have reported wastewater viral activity levels as of Aug. 9:

Data collected by the CDC shows that six Midwestern states making up Region 5 had the biggest increase (2.1%) in positive COVID-19 cases from July 28 to Aug. 3, 2024. The data was posted on Aug. 12, 2024.

Note: The CDC organizes positivity rate based on regions, as defined by the U.S. Department of Health and Human Services.

Here's the list of states and their regions' changes in COVID-19 positivity for the past week:

The CDC has not said if KP.3 or KP.3.1.1 have their own specific symptoms. However, Norman previously explained that the symptoms associated with KP.3 are similar to those from JN.1. The government agency outlines the basic symptoms of COVID-19 on its website. These symptoms can appear between two and 14 days after exposure to the virus and can range from mild to severe.

The CDC said you should seek medical attention if you have the following symptoms:

How can we protect ourselves from KP.3, KP.3.1.1, and other variants?

The CDC recommends that everyone 6 months old and older get the updated 2024-2025 COVID-19 vaccine. Norman also recommends that the elderly and those who are immunocompromised should get vaccinated in order to protect themselves from COVID-19.