What to know about the new 'FLiRT' COVID variants that are spreading: Your guide to the latest virus news

A lot has changed since SARS-CoV-2 (the virus responsible for COVID-19) appeared on the world stage four years ago. In 2020, the novel coronavirus infected and upended the daily lives of millions of people, but today life has mostly returned to normal: Restrictions have been lifted, people are a lot less cautious, and the etiquette rules around keeping yourself and others healthy aren’t so clear-cut. So if you’re confused about the current state of COVID-19 and how to reduce your risk, here’s a guide with everything you need to know — from variant- and case-tracking to the most up-to-date public health recommendations on masking, vaccines, testing and more.

Variants

• Which COVID variant is dominant right now? Over the course of the past several weeks, a new group of "FLiRT" variants — nicknamed for their mutations — have been on the rise in the U.S. One of them, the KP.2 variant, is now the most dominant form of the virus in the U.S., according to the latest Centers for Disease Control and Prevention (CDC) data. KP.2 accounted for about one in four COVID cases during the two-week period ending in April 27, the CDC estimates. Its close relative, KP.1.1, makes up about 7.5% of cases.

• How are the latest variants different? The FLiRT variants are distant cousins of the previously dominant JN.1 variant, all of which belong to the Omicron family. So far, the symptoms seem to be the same: fever, cough, stuffy or runny nose, sore throat and loss of taste or smell. Like JN.1 , the FLiRT variants appear to be "rather transmissible," according to the data available so far, Dr. William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center, told "Today." The bigger concern is that the FLiRT variants' mutations may make them better at evading immunity from both prior infection and vaccination, he said.

• Are cases currently increasing or decreasing? The CDC has launched a dashboard that tracks COVID levels in wastewater. Currently, wastewater viral activity levels for COVID are "minimal" (the lowest activity category on the CDC's ranking scale) as of late April. This week’s national forecast of hospitalizations from the CDC "predicts 130 to 2,400 daily COVID-19 hospital admissions likely reported on May 27," which is similar to the prediction of 240 to 2,300 daily hospitalizations for the week of May 6. Cases have been trending generally downward since the beginning of 2024. Schaffner told Today that it's too soon to "sound the alarm bells," but warned that the mutations in the FLiRT variants that make it resistant to immunity could lead to an uptick in cases.

Vaccines

• When will there be new vaccines? An updated COVID booster shot can be expected this fall, CDC director Mandy Cohen told Bloomberg. Scientists are still determining which strain of the virus the vaccine should target, a decision that will likely come in May, she said. People who were infected by the JN.1 variant seem to have better protection against the new, but related, FLiRT variants, so the World Health Organization (WHO) is now advising all future vaccine formulations be based on the JN.1. It's not yet clear whether the U.S. vaccines to come this fall will be based on this variant.

• Who should get boosted? The CDC recommends that all adults ages 65 and older get a booster dose of the updated monovalent vaccine that became available in September. “Most COVID-19 deaths and hospitalizations last year were among people 65 years and older,” Cohen said in a Feb. 28 statement. “An additional vaccine dose can provide added protection that may have decreased over time for those at highest risk.” When the updated shot first came out, in the fall, the CDC recommended that everyone 6 months and older get a booster dose. So far, the agency is not suggesting that younger people get a spring dose. The updated vaccine targets the XBB.1.5 Omicron strain and is expected to be effective against currently circulating variants. Pfizer’s and Moderna’s vaccines, which use mRNA technology, are approved for anyone 6 months and older. Anyone age 12 and older is eligible for the updated Novavax vaccine, which uses a more traditional protein-based approach. But few Americans have taken advantage. As of May 3, 22.5% of adults had received the newest COVID shot, according to CDC data; more than twice as many U.S. adults (48.8%) have gotten a flu shot. Just over 14% of U.S. children have received the updated COVID shot. And a recent study analyzing vaccination coverage and rates of COVID infection in nursing homes from October 2023 to February 2024 found that less than half of nursing home residents (40.5%) were up to date with their shots, the Center for Infectious Disease Research and Policy reports; the South had the lowest rate of vaccination coverage, at just 32.4%.

• Are vaccines free? COVID vaccines are covered by insurance, Medicare and Medicaid. The federal Bridge Access Program provides free COVID vaccines for uninsured and underinsured adults, and the federal Vaccines for Children program provides vaccines for children at no cost. But the U.S. government is no longer buying and distributing vaccines, which initially led to a rocky rollout with some canceled appointments as individual doctors offices, pharmacies and insurance companies handle the process themselves.

• Can you get COVID and flu shots at the same time? Yes. Research shows there’s only a slightly higher chance of experiencing side effects such as pain at the injection site or fatigue, and there’s no decrease in benefit. Experts suggest doing whatever is most convenient, and you can opt for both shots in the same arm or one in each arm.

• Do vaccine cards matter? Most people no longer need to show that they’ve been vaccinated — unless you’re a health care worker or if you work in a high-risk environment, like a college dorm or nursing home. The CDC has stopped printing vaccine cards, but if you still have your card it’s a good idea to treat it like any other medical record and file it away in a safe place. If you’ve lost your card and want proof of vaccination, some states have registries that include adult vaccines, or you can contact the doctor’s office or pharmacy that administered your vaccine, which can provide digital or paper verification.

• What else should I know? USA Today reported that on April 11 the CDC released new data that negates any link between the COVID vaccine and cases of sudden cardiac death, including myocarditis, in young adults. "The data do not support an association of COVID-19 vaccination with sudden cardiac death among previously healthy young persons," the agency concluded.

Isolation guidelines

• How long do you need to isolate if you test positive? Only until you are fever-free for at least 24 hours without medication, according to the latest Centers for Disease Control and Prevention guidelines, published on March 1. The CDC has dropped its previous recommendation that people with COVID stay home and away from others for at least five days. Its new guidance advises people to take the same precautions that they would when sick with other respiratory viruses, like RSV and flu.

• Why are the guidelines changing now? There are two primary reasons the CDC has relaxed its recommendations: The vast majority of Americans now have some immunity against COVID, and the virus is leading to fewer hospitalizations and deaths than in years past. In fact, research published in the agency’s Morbidity and Mortality Weekly Report in June suggests that more than 96% of people 16 and older have antibodies — from previous infection, vaccination or, most commonly, a combination of the two — that fight the COVID virus. As of early May the CDC’s wastewater tracking dashboard indicates a "minimal" activity level for COVID-19.

At-home testing

• Are at-home tests free? As of March 8, the U.S. government’s program offering free COVID tests to be mailed to Americans’ homes has been suspended. According to COVID.gov, the federal government has additional programs that provide free COVID tests “to uninsured individuals and underserved communities,” but anyone wishing to take advantage of these programs must contact an HRSA-funded health center or Increasing Community Access to Testing (ICATT) location.

• What about schools? The U.S. Department of Education announced last fall that schools will be able to order free tests “to supply students, families, staff and larger school communities.” There have been no announcements about changes to this program.

• How accurate are at-home tests? The Food and Drug Administration says that at-home COVID antigen tests (aka rapid tests) are less precise than molecular tests (i.e., the PCR tests performed at a hospital or clinic), and false negatives may be more likely to happen, especially if the test is taken shortly after infection or when you don’t have symptoms. If you get a negative result on an at-home COVID test, the FDA recommends testing again 48 hours later, even if you don’t have symptoms. PCR tests are still considered the gold standard in COVID testing, but experts believe at-home tests should still be able to pick up newer variants.

• Can I use an expired test? The FDA revised expiration dates for some tests to extend them by several months. Follow this link, find your test’s name, click on Extended Expiration Date and check the lot number on your box to see the new expiration date for your test.

Masks

• When do I need to wear a mask? Masking at this point is a personal choice, but the CDC suggests using hospital admission levels in your area to determine whether a mask is necessary. You can check hospital admission levels by county here, with data updated by the CDC weekly. The CDC also recommends that the right times to consider a mask include when there are a lot of respiratory illnesses spreading in your community, when you or those around you have been exposed to, are sick with or recovering from a respiratory illness and when you or those around you are at risk of becoming severely ill from respiratory viruses. This guidance is now written to apply broadly to all viral respiratory viruses, including COVID, flu and RSV.

• Are mask mandates coming back? Cohen told Yahoo Life in December that “we’re in a different place than we’ve been before," and Dr. Anthony Fauci, former director of the National Institute of Allergy and Infectious Diseases, said in September that it’s unlikely federal mask mandates will return. Still, some individual institutions have brought masks back; as respiratory virus season kicked into full gear, hospitals in several states implemented some form of masking requirements. But as COVID cases and hospitalizations have begun to decrease, some of those temporary masking requirements are being lifted.

Testing for international travelers

• When and where are travelers being tested? International travelers arriving in the U.S. at Chicago O’Hare International Airport and Miami International Airport may now be asked to voluntarily take COVID tests, the Centers for Disease Control and Prevention announced on March 12. The nasal sample testing program, which launched in 2021, has been in place at seven international airports over the course of the pandemic. Testing will now happen at nine airports total, including:

• Boston Logan International Airport

• Los Angeles International Airport

• Newark Liberty International Airport in New Jersey

• JFK International Airport in New York City

• San Francisco International Airport

• Seattle-Tacoma International Airport

• Washington Dulles International Airport in Washington, D.C.

• Who will be tested? The program is entirely voluntary. People arriving from outside the U.S. in Miami and Chicago, in addition to the seven preexisting airport testing sites, could randomly be asked to swab their own nose and answer survey questions.

• Why are more airports testing now? A negative test is no longer required to enter the U.S., but airport testing has served as an important early warning signal of coming surges and new variants of the coronavirus that might evade vaccines throughout the pandemic, according to the CDC. “Miami and Chicago enable us to collect samples coming from areas of the world where global surveillance is not as strong as it used to be,” said the CDC’s chief surveillance officer, Allison Taylor Walker. Specifically, surveillance is lacking in South America, Africa and Asia, and many flights from these regions land in Miami and Chicago. The swabs will also be used to monitor flu and respiratory syncytial virus (RSV).

This article was originally published on Jan. 8, 2024 and has been updated.