Six months ago, swine flu emerged as a massive threat to global health. It seemed to come out of nowhere, but our timeline explains how the origins of the H1N1 pandemic go back more than a century ...

Older adults might have some pre-existing immunity to H1N1 swine flu, according to the U.S. Centers for Disease Control and Prevention.

Also like the 1918 strain, H2N2 viruses have not circulated in humans for several decades, but continue to do so among birds and swine 8.

Twelve key events leading up to the emergence of the current pandemic swine-origin influenza A (H1N1) virus are reviewed.

Governments should launch a vaccination programme now to guard against a possible H2N2 flu pandemic, according to an article in the journal Nature.

H2N2 caused a pandemic in 1957, killing a few million people. This strain swapped two of its genes with another bird flu strain to produce H3N2, a grandchild of H1N1 that went pandemic in 1968 ...

The scientists exposed the cells to virus-like particles designed to resemble three different subtypes of flu viruses that have previously caused flu epidemics in humans: H1N1, H3N1 and H2N2.

Vial and packaging for the 1957 H2N2 vaccine, at the National Museum of American History. Producing the inoculation required hundreds of thousands of fertilized chicken eggs per day. National ...

Human influenza A viruses of subtype H2N2 and related H2N2 avian influenza viruses can enter cells through a second receptor. They use an alternative entry pathway." ...

Governments should launch a vaccination programme now to guard against a possible H2N2 flu pandemic, according to an article in the journal Nature.

Human influenza A viruses of subtype H2N2 and related H2N2 avian influenza viruses can enter cells through a second receptor. They use an alternative entry pathway." ...