Influenza A virus subtype H2N2 (A/H2N2) is a subtype of Influenza A virus. H2N2 has mutated into various strains including the "Asian flu" strain (now extinct in the wild), H3N2, and various strains found in birds. It is also suspected of causing a human pandemic in 1889.

The 1957 flu pandemic was caused by influenza H2N2 virus, to which few people had previous exposure. A vaccine was rapidly developed against H2N2, though later assessment showed that more vaccine than usual was needed to produce immunity.

The strain of virus that caused the Asian flu pandemic, influenza A virus subtype H2N2, was a recombination of avian influenza (probably from geese) and human influenza viruses. [9] [25] As it was a novel strain of the virus, the population had minimal immunity.

Jan 2, 2019 · In February 1957, a new influenza A (H2N2) virus emerged in East Asia, triggering a pandemic (“Asian Flu”). This H2N2 virus was comprised of three different genes from an H2N2 virus that originated from an avian influenza A virus, including the H2 hemagglutinin and the N2 neuraminidase genes.

Oct 4, 2016 · Strains of influenza are characterized by two proteins that are on the outer surface of the virus: hemagglutinin and neuraminidase. This is where the "H" and "N" in the name come from. The proteins can be seen in the picture above, represented by the blue "spikes" on the outside of the virus.

For five days and nights, his team tested it against blood from thousands of Americans. They found that this strain, H2N2, was unlike any flu that humans were known to have encountered.

Sep 15, 2009 · Influenza A viruses of 3 subtypes—H1N1, H2N2, and H3N2—have been endemic in humans. Influenza A H1N1 caused the 1918 pandemic and circulated in humans until 1957 when a new pandemic H2N2 virus replaced it; which …

The Asian H2N2 influenza virus was characterized by early summer, 1957, but significant mortality in the United States did not occur until October. In 1968, the pandemic wave of mortality in Europe crested a full year after the pandemic strain first arrived.

… known as influenza A subtype H2N2. Research has indicated that this virus was a reassortant (mixed species) strain, originating from strains of avian influenza and human influenza viruses. In the 1960s the human H2N2 strain underwent a series of minor genetic modifications, a process known as antigenic drift.

Jun 13, 2020 · Worldwide, the pandemic, sparked by a new H2N2 influenza subtype, would result in more than 1 million deaths.