Herd Immunity: Simply being born before 1957 gave you natural immunity to H1N1 flu when it reappeared in 1977-Atomic Bulletin, 3/31/2014, CDC, 1/2006

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The 1977 H1N1 flu “pandemic spread rapidly worldwide but was limited to those under 20 years of age.” Persons born prior to 1957 had existing natural immunity:

March 31, 2014, “Threatened pandemics and laboratory escapes: Self-fulfilling prophecies," Bulletin of the Atomic Scientists, Martin Furmanski

“Human H1N1 influenza virus appeared to go extinct in 1957 after the H2N2 pandemic virus appeared.

Human H1N1 virus reappeared in 1977… The 1977 pandemic spread rapidly worldwide but was limited to those under 20 years of age: Older persons were immune from [their] exposures before 1957....Mercifully it caused mild disease, and fatalities were few. It continued to circulate until 2009, when the pH1N1 virus replaced it….

Virologists, using serologic and early genetic tests soon began to suggest the cause of the reappearance was a laboratory escape of a 1949-1950 virus,…By 2010, researchers published it as fact: “The most famous case of a released laboratory strain is the re-emergent H1N1 influenzaA virus which was first observed in China in May of 1977 and in Russia shortly thereafter.”…

There has been virtually no public awareness of the 1977 H1N1 pandemic and its laboratory origins.…The consequences of escape of a highly lethal avian virus with enhanced transmissibility would almost certainly be much graver than the 1977 escape of a “seasonal,” possibly attenuated strain to a population with substantial existing immunity.”…

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Added: CDC citation for above 1977 event, published Jan. 2006:

A 1977 version of H1N1 had almost no effect on persons over age 25, specifically persons born before 1957, as they had acquired permanent natural immunity from exposure to it prior to 1957:

Jan. 2006, “Influenza Pandemics of the 20th Century,” cdc.gov, Edwin D. Kilbourne*, Author affiliation: *New York Medical College, Valhalla, New York, USA

“Abstract

Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968….All 3 have been informally identified by their presumed sites of origin as Spanish, Asian, and Hong Kong influenza, respectively. They are now known to represent 3 different antigenic subtypes of influenza A virus: H1N1, H2N2, and H3N2, respectively. Not classified as true pandemics are 3 notable epidemics: a pseudopandemic in 1947 with low death rates, an epidemic in 1977 that was a pandemic in children, and an abortive epidemic of swine influenza in 1976 that was feared to have pandemic potential…

It quickly became apparent that this [1977] rapidly spreading epidemic was almost entirely restricted to persons <25 years of age, and that, in general, the disease was mild, although characterized by typical symptoms of influenza….

Where had the virus been that it was relatively unchanged after 20 years?..

Had the virus been in a deep freeze? This was a disturbing thought because it implied concealed experimentation with live virus, perhaps in a vaccine.”…

 

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