The Centers for Disease Control (CDC) is closely monitoring an emergent and growing COVID-19 strain—KP.2—which represents nearly a third (28.2%) of all circulating variants in the last two weeks.

Variant Proportions. CDC.

CDC data shows that the KP.2 variant has grown in the past several weeks. During March, for example, the strain barely made up 2% of circulating variants. By early to mid-April, however, that number jumped to nearly 7%.

Variant Proportions. CDC.

Suraj Saggar, MD, chief of infectious disease at Holy Name Medical Center in Teaneck, NJ, tells MDLinx.com that the nickname “FLiRT” refers to technical names of the virus’ mutations—one which includes the letters ‘F’ and ‘L’ while the other includes ‘R’ and ‘T.’ The variants are part of the Omicron family.  

Viruses like SARS-CoV-2 mutate frequently—doing so to evade recognition by killer antibodies. Sometimes, mutations weaken them. Other times, it improves their ability to bind to receptors. “This is a cycle we have seen many times with SARS-CoV-2. The fact that these different variants are picking up the same mutations tells virologists that this combination of mutations is helping the virus accomplish these goals most efficiently,” according to an interview with Andy Pekosz, PhD, a professor in Molecular Microbiology and Immunology published by Johns Hopkins Bloomberg School of Public Health.

What to know about covid flirt variants | johns hopkins | bloomberg school of public health.

“The family of variants…have some concerning features, like changes in the spike protein, which is used by the virus to access the human body. It is a target of the antibodies produced by vaccines and natural infection and thus would be expected to cause ‘escape infections’...to be more transmissible,” Dr. Saggar notes. 

Experts are watching the variant closely—and potentially expecting a summer spike in COVID-19 cases. It is not known whether the variant causes more severe illness, as it depends on a patient’s immunity and the virulence of the infection, explains David Cutler, MD, board-certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA.

KP.2 is now the dominant COVID variant. Experts say US may see a summer increase in cases. ABC News.

“The fact that about 97% of Americans have some degree of immunity against [COVID-19] through vaccination, prior infection, or both makes it difficult to assess the risk posed by any new COVID variant,” he adds. 

“If someone is exposed to a variant to which they have potent immunity, then they may not get infected at all, acquire an asymptomatic infection, or be mildly ill,” he explains. “However, a novel variant—[like KP.2]—which evades existing immunity poses the risk of more severe infection, and even hospitalization or death,” Dr. Cutler says. 

Since the end of 2023, the CDC’s COVID-19 Wastewater Viral Activity tracker shows a marked reduction in levels, which could indicate that the virus isn’t spreading like it was, Dr. Cutler adds. As the CDC explains, experts can better understand the spread by examining the wastewater.

Wastewater Surveillance. CDC.

“Wastewater surveillance can provide an early warning of COVID-19’s spread in communities. People infected with SARS-CoV-2 can shed the virus in their feces, even if they don’t have symptoms. The virus can then be detected in wastewater, enabling wastewater surveillance to capture presence of SARS-CoV-2 shed by people with and without symptoms,” the CDC says.

National Wastewater Surveillance System (NWSS). CDC.

Dr. Cutler says the core COVID-19 symptoms haven’t changed—and Dr. Saggar echoes this sentiment. Patients should still look out for fever or chills, cough, sore throat, shortness of breath, fatigue, muscle aches, headache, loss of taste or smell, congestion and runny nose, or gastrointestinal issues. “As new variants appear and it is known that asymptomatic people can spread disease, there are no guarantees against acquiring infection,” Dr. Cutler says. 

Patients should also be encouraged to keep up to date with their COVID-19 vaccinations, practice good hygiene, and avoid crowded and unventilated spaces. He says wearing a well-fitting N95 mask is also key. 

“According to the CDC, only 22.6% of adults reported having received an updated 2023-24 COVID-19 vaccine since September 2023,” Dr. Saggar adds. “Given the population of people with waning immunity it increases our susceptibility to a wave.”