What is new about the latest COVID-19 variant KP.3.1.1?
September 6, 2024
Jeremy Alfred
According to the CDC’s COVID-19 virus surveillance system, a new variant of the SARS-CoV-2 virus called KP.3.1.1 has become increasingly dominant in the U.S. The strain emerged at the end of May 2024 and is currently estimated to account for 42.2% of all COVID-19 infections in the U.S.
The SARS-CoV-2 KP.3.1.1 strain has evolved from the JN.1 variant that dominated the U.S. during January of 2024, accounting for 86% of all COVID-19 infections at the time. Both JN.1 and KP.3.1.1 have evolved from the omicron variant first identified in late November of 2021.
Structurally, the KP.3.1.1 virus is similar to JN.1. Compared to JN.1, there are only 2 changes in the spike protein- substitution of one amino acid, and deletion of another. Nevertheless, the two small changes have seemingly had a big impact on the characteristics of the virus.
Characteristics of KP.3.1.1
According to newly published research from Kaku et. al.,
KP.3.1.1 multiplies more efficiently than JN.1, which could increase its spread.
KP.3.1.1 has higher infectivity than JN.1 in the lab, which could indicate higher infectivity in general.
KP.3.1.1 is better than JN.1 at evading neutralization from antibodies, indicating that immunity gained from past vaccinations or infections may not work as well.
Are the current vaccines effective against KP.3.1.1?
On August 22, 2024, the FDA approved and authorized 2024–2025 Moderna and Pfizer-BioNTech COVID-19 vaccines. These vaccines are generated against the JN.1 variant. JN.1 variants currently account for less than 2% of COVID-19 infections in the US. However, since KP.3.1.1 is structurally similar to JN.1, the immunity gained from these vaccines is expected to reduce the severity of infection from KP.3.1.1.
Symptoms of COVID-19 from KP.3.1.1 infection
COVID-19 infection from the KP.3.1.1 variant results in the same symptoms as the infections from previous strains. The development of symptoms varies from person to person. Depending on their immune status, infected people may not experience any symptoms, very mild symptoms, or severe symptoms.
The symptoms of a current COVID infection may include:
You can test for KP.3.1.1 infection using a COVID-19 at-home antigen detection kit. The kits from previous years still detect the newer variants of the SARS-CoV-2 virus such as KP.3.1.1 efficiently. The federal government will start distributing free at-home COVID tests available through USPS again at the end of September. Antigen detection kits can miss the virus if the viral level is low such as too early in an infection. PCR-based tests are highly accurate and can detect minute amounts of virus from the nasal swab or saliva samples. At-home saliva-based sample collection kits for antigen+PCR COVID tests are available from Fast Lab Technologies.
Next steps if you have negative results
If your test results are negative, and you feel no symptoms, you possibly do not have a COVID-19 infection. You also may have tested too early, and the infection has not set in yet. If you suspect you have been around someone with COVID-19, you may test again after 3-5 days. Meanwhile, exercise good hygiene and caution to not get secondary infections, and keep an eye on your symptoms.
Next steps if you have positive results
If you tested positive, that means you have COVID-19 infection. Get rest as your body recovers from the infection. At-home remedies such as honey lemon tea, and soups with healing herbs can be helpful to reduce inflammation and speed up your recovery. Seek medical attention if you do not feel significantly better in a week, or if your cough lingers on for more than a month.
Seek emergency care if you experience serious symptoms such as excessive difficulty in breathing, lips, face, or nails turning blue, a wheezing cough, chest pain, sudden confusion, and trouble waking up and staying awake.
The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.