1957 58:"亚洲型流感"H2N2大流行

1957-58：“亚洲型流感”H2N2大流行1957-58: "Asian flu" H2N2 Pandemic

该病毒首先在中国得到确认，粗略估算导致七万美国人死亡。该病毒自1968年起就没在人类中间流行了，因此，三十岁以下的人都不具备该病毒的免疫力。得益于先进的科学技术，这种病毒很快得到确认，至1957年8月，就能有限制地供应疫苗了。虽然如此，在1957年秋季及1958年1至2月还是爆发了两次传染高潮。老年人死亡率最高。

First identified in China, this virus caused roughly 70,000 deaths in the United States. Because this strain has not circulated in humans since 1968, no one under 30 years old has immunity to it. The virus was quickly identified, due to advances in scientific technology, and a vaccine was available in limited supply by August 1957. Still, two waves of infection struck, in the fall of '57 and then January-February of '58. The elderly had the highest death rates.