The Russian Flu killed 700000 people in 1977, many scientists now believe it may have resulted from a lab leak – Hot Air

In nature, the influenza doesnt stay unchanged for 27 years as it circulates. So the truth that the “Russian flu” was nearly identical to the earlier pressure eventually caused the conclusion that the Russian influenza was likely the result of a lab leak or possibly a stopped working attempt to inoculate individuals with live attenuated infection.
In a term paper released in the journal Nature in 1978, a team of researchers from The City University of New York discovered that the 1977 infection was genomically comparable to the 1950 virus– practically as though the viral development had actually been frozen in time.
It might be possible for an unexpected mutation to develop that resembles a variation from the past– however the scientists considered it was not plausible to hypothesize that such back anomalies accidentally produced a strain so comparable to something that flowed 27 years earlier.
This next bit is quite striking because of present occasions:
A 1978 study by scientists from the Chinese Academy of Medical Sciences revealed that the virus mainly affected those below the age of 20– providing support to the theory that those above that age had already been exposed to the exact same infection before, and hence had established immunity.
In the same paper, however, the group dismissed the laboratory leakage theory in one sentence, stating that none of the “labs concerned” had been working or saving with the H1N1 for a long time.

In 1977 a flu broke out in northeast China which eventually spread to Russia and then around the world. Researchers who analyzed its DNA concluded it was nearly similar to a previous strain of the influenza infection which had actually caused a break out between 1949 and 1950.

As this 2015 paper explains, a laboratory leakage (or additionally a stopped working immunization effort with live attenuated infection) is now thought about the most likely explanation for the Russian influenza as alternate descriptions have been found to be unconvincing. Again, see if this doesnt sound familiar:
A biosafety lapse in a lab is now most frequently pointed out as the reason for the 1977-1978 reemergence of the H1N1 influenza virus stress (Fig. 2). The evidence in favor of this possibility is the clear abnormal origin of the infection and its temperature level of sensitivity, suggesting lab manipulations. At the time of the epidemic, however, the World Health Organization excluded the lab mishap possibility after discussions with influenza infection laboratory scientists in the Soviet Union and China, discovering that “the laboratories concerned either had never ever kept H1N1 virus or had not worked with it for a very long time”
Theres a graphic showing how various theories have been proposed and discussed by researchers throughout the years. Because about 2008, the lab leakage seems to be the dominant explanation:

However the author of the paper appears to think its more most likely the release was the outcome of a vaccine trial utilizing live attenuated virus which wasnt sufficiently attenuated.
There are 2 elements that indicate the 1977 epidemic as arising from vaccine challenge or trials: (i) live attenuated influenza virus (LAIV) research study was extensive at the time, and (ii) a 1976 H1N1 swine flu break out was feared to have pandemic capacity and led to a resurgent interest in H1N1 protection and research study (12 ).
In between 1962 and 1973, almost 40,000 children took part in eight LAIV trials in the USSR (13 ). Researchers at the Peking Vaccine and Serum Institute in China likewise carried out medical trials using live vaccines during the very same period (1 ). In addition, there are records of the mass production of a live H1N1 vaccine in Odessa, USSR, in 1977 (14, 15). In the early days of research in the 1940s, LAIVs were often able to restore virulence upon administration to human beings and cause illness (16 ). In addition, lots of stress isolated from the 1977 outbreak (for instance, the A/Tientsin/78/ 77 isolate) were temperature delicate (ts), meaning that the virus could not replicate at higher temperatures. Temperature level of sensitivity typically happens only after a series of laboratory controls, typical in generation of LAIVs, and is used as a biological marker of attenuation. While not all of the 1977-1978 pressures were temperature sensitive, a comparison of all 1977 strains shows a greater prevalence of the ts phenotype than in 1950 strains, supporting the claim that the break out might have arised from attempts at attenuation for vaccine functions (1, 17).

At the time of the epidemic, nevertheless, the World Health Organization excluded the laboratory accident possibility after conversations with influenza infection lab scientists in the Soviet Union and China, finding that “the laboratories worried either had never kept H1N1 infection or had actually not worked with it for a long time”
In addition, lots of strains isolated from the 1977 break out (for example, the A/Tientsin/78/ 77 isolate) were temperature sensitive (ts), implying that the virus might not replicate at higher temperature levels. Whatever the precise cause, most experts now believe that the “Russian flu” of 1977 was caused by a virus which had been gathered at some point around 1950, worked on in a lab and then basically released back into the world by accident. Flu viruses merely dont hibernate for 27 years and then suddenly cause an outbreak in a the same form.

Scientists who analyzed its DNA concluded it was almost similar to a previous pressure of the flu virus which had triggered a break out between 1949 and 1950.

Whatever the precise cause, the majority of specialists now believe that the “Russian influenza” of 1977 was triggered by an infection which had been collected at some point around 1950, worked on in a lab and then basically released back into the world by accident. The Russians and the Chinese rejected having actually done any such thing and the WHO supported those denials at the time, however 3 decades later most scientists now believe the rejections need to be false. Flu viruses simply dont hibernate for 27 years and then all of a sudden trigger a break out in an unchanged kind.