A new COVID-19 variant called HV.1 has become the dominant strain in the United States and now accounts for nearly one-third of cases nationwide.
The highly infectious omicron subvariant has been circulating in the U.S. since the summer. In October, HV.1 rapidly gained speed and overtook other variants, including EG.5, aka Eris, to become the most prevalent strain, according to the U.S. Centers for Disease Control and Prevention.
During a two-week period ending on Nov. 11, HV.1 accounted for 29% of new COVID-19 infections in the U.S., per the CDC. After HV.1, the next most common variant was EG.5, which made up about 22% of cases, followed by FL.1.5.1 or “Fornax,” and XBB.1.16 or “Arcturus.” Unlike its predecessors, HV.1 has yet to gain a catchy nickname.
All of the COVID-19 variants that have become dominant in the U.S. over the last year are descendants of omicron, which began circulating in November 2021.
The emergence of HV.1 demonstrates how the SARS-CoV-2 virus, which causes COVID-19, is able to mutate and give rise to new, highly contagious variants.
HV.1’s reign comes as the U.S. enters the thick of respiratory virus season and health officials roll out updated COVID-19 vaccines. While the new booster still offers protection against newer variants, very few Americans have gotten the shot so far, TODAY.com previously reported.
As HV.1 continues to spread, many are curious if the new variant is more contagious or severe than previous strains, whether it’s causing different symptoms, and when they should get the updated COVID-19 vaccine. Here’s what we know about HV.1 so far.
What is HV.1, the new COVID variant?
HV.1 is part of the omicron family. “You can almost think of HV.1 as a grandchild of omicron,” says Schaffner. HV.1 is a sublineage of omicron XBB.1.9.2 and a direct descendent of EG.5, according to the CDC’s SARS-CoV-2 lineage tree.
“The COVID family of viruses likes to mutate. We’ve all learned that by now,” says Schaffner. While HV.1 is mutated, it’s still very close to the existing omicron subvariants, Schaffner explains.
For the most part, scientists are not concerned about new variants like HV.1, which look very similar to strains we’ve already seen before, NBC News reported.
However, there are a few highly mutated strains that have set off alarm bells. These include BA.2.86 or Pirola, which has an extra 36 mutations that differentiate it from XBB.1.5., and a newer variant called JN.1, which has one more mutation than Pirola.
Fortunately, neither BA.2.86 nor JN.1 are common in the U.S. right now, according to the CDC — JN.1 is so rare that it makes up fewer than 0.1% of SARS-CoV-2 cases.
As for HV.1, it rapidly gained steam after it was first detected this past summer. In late July, HV.1 accounted for just 0.5% of COVID-19 cases in the U.S., CDC data show. By Sept. 30, HV.1 made up 12.5% of cases, and by November, it was the dominant strain.
Is HV.1 more transmissible?
“One of the characteristics of this entire omicron family is that they are highly transmissible,” says Schaffner.
Just like other omicron subvariants, HV.1 is highly transmissible, Dr. Priya Sampathkumar, infectious disease specialist at the Mayo Clinic, tells TODAY.com.
Sometimes, mutations can enable a new variant to spread more effectively or quickly, per the CDC.
Right now, it appears that HV.1 could be better at spreading from person to person than previous strains, NBC News reported. The increased transmissibility of HV.1 likely explains how it became dominant so quickly in the U.S., Schaffner notes.
It also appears that HV.1 could also be slightly better at escaping prior immunity to COVID-19, but not enough to cause alarm, Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, told NBC News.
“The problem is that most people’s immunity has faded from past outbreaks and our vaccine uptake is still very low … so it’s too soon to draw any conclusions about HV.1 (evading) immunity from prior infection or vaccination,” says Sampathkumar.
Although it is more transmissible, HV.1 does not appear to produce more severe disease or lead to more hospitalizations, Schaffer says.
What remains unclear is whether HV.1 could cause a major uptick in COVID-19 cases. “If there’s vast numbers of people getting infected, even if the disease for most people isn’t very severe, we will see an uptick in hospitalizations and deaths,” says Sampathkumar.
Health officials are monitoring HV.1 closely, but low levels of testing have made it harder to accurately track new variants, experts note.
What are HV.1 symptoms?
The symptoms caused by infection with HV.1 are similar to those caused by recent variants, says Schaffner, which include:
Sore throat
Congestion or stuffiness
Runny nose
Cough
Fatigue
Headache
Muscle aches
Fever or chills
“Congestion, sore throat, and dry cough seem to be the three most prominent symptoms right now,” says Schaffner.
Increasingly, doctors report that COVID-19 symptoms appear to follow a pattern of being concentrated in the upper respiratory tract, starting with a sore throat and followed by congestion or a runny nose, NBC news reported.
Coughing isn’t typically a primary symptom, but it can persist. “The virus seems to produce a kind of chronic bronchitis so that you can have a cough syndrome that lasts beyond the period where you’ve recovered from other symptoms,” says Schaffner.
“I haven’t really heard of anything very different or any new symptoms that may raise alarms,” says Sampathkumar.
Another trend is that COVID-19 seems to be causing milder illness, likely because people have some prior immunity. “By milder, we mean it doesn’t require hospitalization even though you can feel quite miserable for several days,” says Schaffner.
