LB.1 is the latest COVID-19 subvariant to circulate and attract attention in the U.S. Emerging on the heels of the “FLiRT” variants, including KP.3 and KP.2, this highly contagious strain is infecting an increasing proportion of people.
In the United States, the number of infected people and emergency room visits is increasing nationwide, and there are concerns that the infection will spread over the summer.
LB.1 is currently the third most common COVID-19 variant in the United States, behind the dominant KP.3 and KP.2. Centers for Disease Control and Prevention.
As of June 22, KP.3 accounts for an estimated 33% of cases in the U.S. The next most common variant is KP.2, which accounts for approximately 21% of cases, followed by LB.1, which accounts for 17.5% of cases.
The percentage of cases caused by LB.1 has more than doubled since the end of May, according to CDC data. Some experts say the new variant is FLiRT variants In the coming weeks.
Although the overall number of COVID-19 cases, including hospitalizations and deaths, is relatively low compared to the winter, it is clear that the virus is on the rise. Is the country facing a summer surge in infections?
Here’s what we know so far about summer COVID-19 trends and the new LB.1 variant.
Will there be a summer surge?
In recent weeks, most U.S. states have seen an increase in cases, particularly in the West. CDC estimates As of June 25, COVID-19 case numbers are increasing or expected to increase in 44 states, stable or uncertain in five states, and decreasing in Hawaii.
“Right now (early July), we’re not seeing a national surge in cases, but we are seeing cases increasing in some areas and plateauing in others,” Dr. Andrew Pecos, a virologist at Johns Hopkins University, told TODAY.com. Pecos added that the country is likely at the beginning of a wave of infections, but it remains to be seen what COVID-19 trends will be over the summer.
As of June 22, the test positivity rate was 8%. According to the CDC:That’s up 1.4% from the previous week but still below the winter peak of 12%. CDC Map Test positivity rates are highest in California and the Southwestern United States
Viral activity in wastewater While the numbers are at “low” levels nationwide, they were at “high” or “very high” levels for much of the winter. (The CDC does not track the total number of new COVID-19 cases in the U.S.)
Dr. William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center, said what we’re seeing now is just an expected “surge. Unlike the flu, COVID-19 is not seasonal, meaning it continues to spread through the summer, but these surges are much smaller than the winter surges, he added.
As summer vacation travel peaks and people flock to air-conditioned rooms to escape the heat, heat waveCOVID-19 cases are expected to continue to rise, and “if it’s not spreading in your area yet, it will probably spread after the Fourth of July travel is over,” Schaffner said.
What is LB.1?
LB.1 is part of the Omicron family, or the most recent great-grandchild, so to speak, Schaffner said. JN.1prevailed during most of the winter and spring.
“LB.1 is closely related to the FLiRT variant, but has some unique mutations in different parts of the spike protein,” Pekosz said, including key mutations that affect LB.1’s ability to evade the immune system.
“Such mutations have been seen before with other variants (including JN.1). … It does not appear to be of particular concern or a sign of a dramatic change in the virus,” Pecos added.
Experts say the emergence of LB.1 is part of a continuing trend: The SARS-CoV-2 virus mutates to produce new variants that are better able to evade immunity and outcompete other strains until new strains emerge.
More than 97% of people in the U.S. have natural or vaccine-induced antibodies to COVID-19, but these fade over time. According to the CDC:.
Is LB.1 more contagious?
The Omicron variant is characterized by its extreme transmissibility. “LB.1 is extremely transmissible and spreads very easily,” Schaffner said.
How does LB.1 compare to other new strains? “It’s too early to tell, but right now there’s no indication that it’s more transmissible than the FLiRT variant,” Dr. Bernard Cummins, medical director of infection prevention for Mount Sinai Health System, told TODAY.com.
“While they may be more likely to evade infection or the immunity gained through the vaccine, they have not been shown to be more dangerous than previous variants,” Cummins said.
The recent increase in cases appears to be driven by a combination of new variants, including the LB.1 and FLiRT strains. But reduced testing and genomic surveillance have made it harder to track the virus precisely. “It’s becoming harder to get an accurate picture of how fast the variants are increasing,” Pecos said.
What are the symptoms of LB.1?
Experts stress that LB.1 does not appear to cause any clear or new symptoms, and there are no signs it causes more severe illness.
Symptoms of LB.1 are very similar to those caused by FLiRT variants and include:
Schaffner said the new virus appears to generally cause milder infections, but COVID-19 can still cause a range of illnesses.
“Some people will have the classic symptoms of sore throat, runny nose, cough and slight fever,” says Dr. Paul Sacks, clinical director of infectious diseases at Brigham and Women’s Hospital and professor of medicine at Harvard Medical School. He told NBC News“Other patients have minimal respiratory symptoms and mostly nausea and diarrhea. Symptoms range from A to Z or even more.”
And “some people will experience symptoms severe enough that they will be hospitalized,” Cummins told TODAY.com — specifically, high-risk groups like those over 65, those with underlying medical conditions, and those who are immunocompromised.
“Right now, there are no symptoms that would say, ‘You probably have COVID,'” Dr. Steven Farr, a family physician in Jackson, Alabama, and president of the American Academy of Family Physicians, told NBC News. “Without testing, we can’t know for sure.”
Emergency department visits due to COVID have increased by 23% over the past week but remain relatively low, and hospitalization rates have remained stable. According to the CDC:.
Schaffner noted that antiviral drugs such as paxlovidone are effective against LB.1 and other recent strains.
Does the vaccine prevent LB.1?
“The current vaccines are effective at preventing severe disease,” Schaffner said. 2023-2024 COVID-19 Booster Update A vaccine targeting the XXB.1.5 strain is still available. The CDC recommends High-risk groups will receive additional doses.
Experts emphasize that the improved vaccine for 2024-2025, which will be released this fall, is also expected to be effective in preventing the disease. “LB.1 is closely related to KP.2, and it is likely that KP.2 will be the strain targeted by this fall’s vaccine,” Pecos said.
“The data so far shows that even if the vaccine is not an exact match for what’s circulating, there will be cross-reactivity and you will still get some protection,” Cummins said.
Experts are recommending that everyone who is eligible get the latest dose of the 2024-2025 COVID-19 vaccine this fall.
COVID Guidelines 2024
Experts emphasize that if you experience symptoms of COVID-19 or suspect you may have it, get tested as it is a key step in protecting yourself and preventing the spread of the virus.
Cummins noted that PCR and antigen tests can detect LB.1 and other new variants. If you use an antigen test: FDA Recommendations This is to avoid false negative results.
of The CDC recommends People who test positive should stay home and avoid contact with others while they are sick. Officials previously recommended avoiding contact with others for at least five days after testing positive. Quarantine guidelines have changed Once the fever subsides without medication, you can resume normal activities. and Symptoms have improved for at least 24 hours.
“If you’re in a high-risk group and you test positive for COVID-19, you’re given paxlobriand to prevent serious illness,” Schaffner said.
How to protect yourself from the LB.1 variant
As COVID-19 cases continue to rise this summer, please consider taking additional steps to protect yourself and others. The CDC recommends people:
Get the latest information on COVID-19 vaccines.
Please wear a mask in crowded indoor spaces.
Please practice thorough hand hygiene.
Cover your mouth when coughing or sneezing.
Improves ventilation.
Please practice social distancing.
This article was originally published on TODAY.com