Two new coronavirus subvariants, collectively known as FLiRT, are gradually displacing the dominant winter strain ahead of a potential increase in coronavirus infections in the summer.
The new FLiRT subvariants, officially known as KP.2 and KP.1.1, are believed to be about 20% more transmissible than their parent, JN.1, which is the predominant winter subvariant. said infectious disease specialist Dr. Peter Chin-Hong. Expert at the University of California, San Francisco.
The two FLiRT variants combined accounted for an estimated 35% of coronavirus infections in the United States in the two weeks starting April 28, according to the Centers for Disease Control and Prevention. In contrast, JN.1 is now thought to account for 16% of infections. It was thought that more than 80% of cases occurred in the middle of winter.
“It's been quite some time since a new dominant variant emerged in the United States,” said Dr. David Bronstein, an infectious disease expert at Kaiser Permanente Southern California. “We're seeing increased transmissibility in these variants inherited from previous variants, making them more easily transmitted from person to person. So that's the real concern for FLiRT. It is a matter.”
The largest FLiRT subvariant, KP.2, is particularly rapidly increasing as a proportion of coronavirus infections. As of late March, it accounted for only 4% of the estimated number of infected people nationwide. It was recently estimated to account for 28.2%.
The new subvariant is called FLiRT, after the mutation of the new coronavirus that evolved. “So instead of an ‘L’ there’s an ‘F’. And instead of a “T” there's an “R”. And I added an 'i' to make it cute,” Chin-Hong said.
Despite increased transmissibility, the new mutation does not appear to cause more severe disease. And given that the new subvariant is only slightly different from the winter version, the vaccine is expected to continue to work well.
The entry of subvariants also comes as the number of people hospitalized due to the new coronavirus has hit an all-time low. Hospitalizations for the week ending April 27 were 5,098, one-seventh of this winter's peak of 35,137 hospitalizations reported for the week ending January 6.
But starting May 1, hospitals across the country are no longer required to report COVID-19 hospitalizations to the U.S. Department of Health and Human Services. From now on, only voluntarily submitted data will be published nationwide.
In Los Angeles County, coronavirus infection levels appear to be in a lull. For the week ending April 27, coronavirus concentrations in Los Angeles County's sewage reached 8% of their winter peak.
Still, some doctors say they wouldn't be surprised if coronavirus cases rise in the summer, as they have in previous seasons.
“We expect that by summer, people's immunity will be a little lower,” Chin-Hong said. Older adults and people with weakened immune systems are “potentially at risk for more severe illness.”
Additionally, in the summer, people often gather indoors to avoid the heat, and crowded public places can increase the risk of infection.
Chin-Hong, who treats patients with severe coronavirus infections at the University of California, San Francisco, said, “They are either very old or have very weakened immune systems and have not received the latest vaccinations.” There wasn't,” he said.
The potential for the FLiRT subvariant to spread more easily highlights the importance for those most at risk to stay up-to-date on vaccinations and stay away from people who are sick. Yes, doctors say.
And while the likelihood of long-lasting coronavirus outbreaks is likely lower than it was at the beginning of the pandemic, it's still here.
Data shows many people have not recently received a coronavirus vaccination. In the week ending February 24, 29% of seniors nationwide received the latest vaccine, which became available in September. In California, about 36% of seniors had received their latest dose as of April 30.
“We're still seeing hospitalizations, bad outcomes and even people dying from COVID-19. It's not going away,” Bronstein said. “The good news is…the vaccines are very good at protecting you from hospitalization, severe outcomes and death.”
More than 42,000 coronavirus deaths were recorded nationwide between October and April, according to the CDC. This is significantly higher than the estimated 24,000 deaths from influenza during the same period.
Still, this number is lower than the comparable period of the previous season, when more than 70,000 COVID-19 deaths were reported. And that number is far lower than during the first two devastating pandemic winters. More than 272,000 deaths were recorded between October 2021 and April 2022. From October 2020 to April 2021, that number was over 370,000.
In February, the CDC recommended that people 65 and older receive a second dose of a modern vaccine only if at least four months have passed since the previous shot. The CDC also says everyone 6 months and older should be up to date with the vaccine.
“The most important thing people can do right now is get vaccinated,” Bronstein said. He suggested that especially vulnerable people continue to wear masks whenever possible, especially in places like crowded airports and airplanes.
Additionally, he said it's important for people who are sick to stay home to avoid spreading germs to others, especially the elderly. And if a sick person must leave their home, they must wear a mask around others.
“Even in the summer, symptoms that feel like a cold may actually be COVID-19,” Bronstein says. “If you are sick, we need you to get tested as much as possible, stay home and make sure your symptoms are less severe before returning to normal activities.”
The state of California recommends people with symptoms of COVID-19 to stay home until their symptoms are mild and have improved and they have not had a fever for 24 hours without taking medication.
People must also wear masks around others while indoors for 10 days after becoming ill or, if they have no symptoms, after testing positive. People can stop wearing masks sooner if they receive two consecutive negative rapid test results at least one day apart. However, the state Department of Public Health says people should avoid contact with all high-risk people for 10 days.
And ahead of this summer's travel plans, Chin-Hong will consult with health care providers to see if Paxlovid can be prescribed to older adults without interfering with other medications if they are infected with COVID-19. I suggested. Paxrobid is an antiviral drug that reduces the risk of hospitalization and death when taken by people with mild to moderate disease who are at risk of severe COVID-19 infection.
Chin-Hong also said it makes sense for health care providers to prescribe paxlobid as a “just in case” prescription for high-risk people who plan to travel to places where the drug is not readily available. It suggests that there is. Paxlobid is fully approved by the U.S. Food and Drug Administration, giving clinicians discretion and giving healthcare providers greater freedom to decide when to prescribe the drug.
Earlier this year, another drug became available to protect the most vulnerable, including cancer patients and organ transplant recipients. It's a monoclonal antibody called Pemgarda, which is given intravenously and can be given once every three months. It has been authorized for emergency use by the FDA and is administered prophylactically to help prevent COVID-19 infection if the person taking it is later exposed to an infected person.
Expectations are also rising that a new version of the coronavirus vaccine will be available, perhaps by September. It could be designed against the JN.1 strain that emerged last winter, but it's also possible that authorities decide it should be designed against the growing FLiRT subvariant, Chin- Hong said.
