After 10 years of evolution, the 1957 flu virus disappeared, having been replaced through antigenic shift by a new influenza A subtype, H3N2, which gave rise to the 1968 flu pandemic.

The 1957 flu pandemic was deadly, but milder than the 1918 event. The virus caused an estimated 70,000 deaths in the United States.

The 1951 influenza epidemic (A/H1N1) caused an unusually high death toll in England; in particular, weekly deaths in Liverpool even surpassed those of the 1918 pandemic.

The estimated number of deaths was 1.1 million worldwide and 116,000 in the United States.

The 1968 flu pandemic was a global outbreak of influenza that originated in China in July 1968 and lasted until 1969–70. The outbreak, which is sometimes called the Hong Kong flu of 1968, was the third influenza pandemic of the 20th century.

It was first reported in Singapore in February 1957, Hong Kong in April 1957, and in coastal cities in the United States in summer 1957. The estimated number of deaths was 1.1 million worldwide and 116,000 in the United States.

The 1957–1958 Asian flu pandemic was a global pandemic of influenza A virus subtype H2N2 that originated in Guizhou in southern China. The number of deaths caused by the 1957–1958 pandemic is estimated between one and four million worldwide, making it one of the deadliest pandemics in history.

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.

‘London flu’ was a particular form of influenza caused by an influenza virus which had apparently first been identified in India in 1971, but was first identified as a distinct strain in England early in 1972.

In 1976, an outbreak of the swine flu, influenza A virus subtype H1N1 at Fort Dix, New Jersey caused one death, hospitalized 13, and led to a mass immunization program….1976 swine flu outbreak.

The 1968 pandemic was caused by an influenza A (H3N2) virus comprised of two genes from an avian influenza A virus, including a new H3 hemagglutinin, but also contained the N2 neuraminidase from the 1957 H2N2 virus.