Out of curiosity, I looked at the Mayo Clinic site and found this
In the spring of 2009, scientists recognized a particular strain of flu virus known as H1N1. This virus is actually a combination of viruses from pigs, birds and humans. During the 2009-10 flu season, H1N1 caused the respiratory infection in humans that was commonly referred to as swine flu. Because so many people around the world got sick that year, the World Health Organization declared the flu caused by H1N1 to be a global pandemic.
In August 2010, the World Health Organization declared the pandemic over. Since that time, scientists have changed the way they name viruses. The H1N1 virus is now known as H1N1v. The v stands for variant and indicates that the virus normally circulates in animals but has been detected in humans. Since 2011, another strain, H3N2v, has been circulating in humans and also causes the flu. Both strains are included in the flu vaccine for 2018-19.