COVID-19 variant KP.3.1.1 now makes up nearly 40% of cases, new CDC data shows

The KP.3.1.1 COVID-19 variant is the dominant strain of the virus, the latest projections from the Centers for Disease Control and Prevention (CDC) show.

Th e 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.

"KP.3.1.1 is a sub-lineage of KP.3," Norman said.

How are KP.3 and KP.3.1.1 different?

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 updated on Aug. 15 by the CDC showed that 32 states and one territory 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. 15:

Can't see the map? Click here to view it.

Changes in COVID-19 test positivity within a week

Data collected by the CDC shows that four Western states and six territories that makes up Region 9 had the biggest decrease of (-5.8%) in positive COVID-19 cases from Aug. 4 to Aug. 10, 2024. The data was posted on Aug. 16, 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:

• Region 1 (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont): +0.5%
• Region 2 (New Jersey, New York, Puerto Rico, and the Virgin Islands): +3.7%
• Region 3 (Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia): +0.8%
• Region 4 (Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee): +1.5%
• Region 5 (Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin): +1.0%
• Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas): -0.3%
• Region 7 (Iowa, Kansas, Missouri, and Nebraska): +0.8%
• Region 8 (Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming): -0.3%
• Region 9 (Arizona, California, Hawaii, Nevada, American Samoa, Commonwealth of the Northern Mariana Islands, Federated States of Micronesia, Guam, Marshall Islands, and Republic of Palau): -5.8%
• Region 10 (Alaska, Idaho, Oregon, and Washington): -1.2%

The CDC data shows COVID-19 test positivity rate was recorded at 18.1 % for the week of Aug. 4 to Aug. 10, an absolute change of 0.2% from the prior week.

COVID-19 symptoms

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.

These are some of the symptoms of COVID-19:

• Fever or chills
• Cough
• Shortness of breath or difficulty breathing
• Fatigue
• Muscle or body aches
• Headache
• Loss of taste or smell
• Sore throat
• Congestion or runny nose
• Nausea or vomiting
• Diarrhea

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

• Trouble breathing
• Persistent pain or pressure in the chest
• New confusion
• Inability to wake or stay awake
• Pale, gray, or blue-colored skin, lips, or nail beds

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.

Ahjané Forbes is a reporter on the National Trending Team at USA TODAY. Ahjané covers breaking news, car recalls, crime, health, lottery and public policy stories. Email her at aforbes@gannett.com . Follow her on Instagram , Threads and X (Twitter) @forbesfineest.

This article originally appeared on USA TODAY: COVID-19 variant KP.3.1.1 now makes up nearly 40% of cases, new CDC data shows