Dominant Covid strain in the US is a highly contagious variant

12 November 2023 , 16:59

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In late July, HV.1 accounted for just 0.5 per cent of Covid-19 cases in the US (Image: Getty Images/iStockphoto)

A new Covid-19 variant has emerged in the United States and is sweeping across the nation. The new Omicron subvariant is now dominating other strains, including EG.5 aka Eris.

From the end of October, HV.1 has been responsible for more than a quarter of all Covid-19 cases, with health officials examining the new variant in preparation for a possible winter Covid-19 surge. Data from the US Centers for Disease Control and Prevention revealed that HV.1 was responsible for an estimated 25.2 per cent of all new Covid-19 cases during the two-week period ending on October 28.

Following HV.1, the next most common variant in the US was EG.5, which accounted for up to 22 per cent of cases, followed by FL.1.5.1 or "Fornax", and XBB.1.16 or "Arcturus". All of the most prevalent Covid-19 strains in the US are offshoots of Omicron, which first appeared in November 2021.

Whilst overall Covid-19 cases and hospitalisations have been in decline recently, the HV.1 strain is becoming more prevalent - and it's thought the winter season will see a further increase, according to Dr. William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center. Speaking to TODAY.com he said: "You can almost think of HV.1 as a grandchild of omicron".

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The symptoms caused by HV.1 are similar to those caused by more recent variants (Getty Images/iStockphoto)

HV.1 descends from EG.5 and is a sublineage of omicron XBB.1.9.2, according to the CDC's SARS-CoV-2 lineage tree. Schaffner said: "The COVID family of viruses likes to mutate. We’ve all learned that by now," before adding that HV.1 is still very close to the existing omicron subvariants.

NBC News reports that scientists are not overly worried about new variants such as HV.1, but there are several highly mutated strains which are more of a concern. These include BA.2.86 or Pirola, which has an extra 36 mutations that are distinctive from XBB.1.5. Then there is a newer variant called JN.1, which has one more mutation than Pirola.

In late July, HV.1 accounted for just 0.5 per cent of Covid-19 cases in the US, CDC data showed and by September 30, HV.1 made up 12.5 per cent of cases. Then, by November, it was the dominant strain.

Schaffner said the symptoms caused by HV.1 are similar to those caused by more recent variants and include a sore throat, congestion or stuffiness, runny nose, cough, fatigue, headache, muscle aches or chills.

He said: "Congestion, sore throat and dry cough seem to be the three most prominent symptoms right now." All Covid-19 tests will detect HV.1 and testing is vital in order to protect yourself.

“We have treatments that can prevent more serious disease," says Schaffner, but early detection is key. Covid-19 antivirals such as Paxlovid are effective against HV.1 and other variants, but they work best when within five days of symptom onset, TODAY.com previously reported.

Schaffner remains concerned that testing has significantly diminished in the US in the last year.

Charlie Duffield