This flu season looks grim as H3N2 emerges with mutations

"The bleak outlook is driven by a new strain of H3N2, which emerged over the summer (at the end of the Southern Hemisphere's season) sporting several mutations. Those changes are not enough to spark the direst of circumstances-a deadly pandemic-but they could help the virus dodge immune responses, resulting in an outsized number of severe illnesses that could put a significant strain on hospitals and clinics."

"Jim Mackey, who became chief executive of NHS England in April, is bracing for influenza's wrath. "There's no doubt this winter will be one of the toughest our staff have ever faced," Mackey told The BMJ. "Since stepping into this role, the thought of a long, drawn-out flu season has kept me awake at night. And, unfortunately, it looks like that fear is becoming reality.""

"Almost all of the UK cases so far this year have been from influenza A strains, with H3N2 accounting for the lion's share, according to the UK Health Security Agency. The two circulating influenza A strains are the new H3N2 strain and an H1N1 strain, with an influenza B strain circulating at very low rates. In the latest UK data, H3N2 was behind over 90 percent of cases that had their influenza virus type analyzed."

""Of the two seasonal influenza A viruses, the current dominant circulating virus (A/H3N2) tends to cause more severe illness than A/H1N1, particularly in older adults," Antonia Ho, an infectious diseases expert at the University of Glasgow, said in a statement. And the early start of the flu season only makes things worse, since not as many people are vaccinated early on,"

A new H3N2 influenza strain emerged over the summer with several mutations that can help the virus evade immune responses. The strain is not expected to cause a pandemic but may drive an outsized number of severe illnesses that strain hospitals and clinics. In the UK the season began roughly five weeks early and is rising rapidly. Almost all recent UK cases are influenza A, with H3N2 causing over 90 percent of typed infections. H3N2 tends to cause more severe illness than H1N1, especially in older adults. An early season reduces early vaccination uptake and raises risk for the United States.

Read at Ars Technica