Lab leak is the biggest suspect in 1977 flu pandemic. But it took 3 decades to gain currency

The 1977 pandemic — called the 'Russian Flu' — was caused by the Human influenza H1N1 virus. It came to be known as such because it was first reported by the erstwhile Soviet Union.

A healthcare worker labels a sample | Representational image | Bloomberg

New Delhi: Over a year since the Covid pandemic wrought havoc around the world, there are increasing calls for a deeper investigation into claims that the virus behind it got leaked out of a Chinese lab. While the leak theory remains under the scanner in the context of Covid, it has emerged as the most widely accepted explanation for the origin of another pandemic — the 1977 ‘Russian flu’, which reportedly killed over 7,00,000 people worldwide.

The Russian flu has come to be known thus because it was first reported by the erstwhile Soviet Union in 1977.

The pandemic was caused by the Human influenza H1N1 virus, which first came to light during the 1918 ‘Spanish Flu’ pandemic. 

The reason why the Russian flu is believed to be have started with a lab leak is that the H1N1 virus that caused the pandemic was found to be closely related to human influenza viruses that circulated in 1949-1950. Since viruses are known to evolve continuously, this discovery, made in 1978, convinced many scientists that a preserved sample of the virus from mid-20th century found its way out of a lab. 

Over the years, alternative theories about the pandemic’s origin — one such theory is that the virus lay latent in an animal — have been discredited by many scientists.

However, it took three decades for the lab leak theory to gain currency. No scientific paper has so far conclusively proven this theory.

Journey of a virus

When the 1918 pandemic came to an end, the human influenza H1N1 virus was not completely wiped out. It persisted throughout the global population, switching its genome, till it was found to be the cause of another major pandemic — the “Asian flu” — in 1957. The virus lay low for the next 12 years, rearing its head again in 1968 as the “Hong Kong” virus, which also caused a pandemic.

In 1977, another outbreak occurred in the far east region of the then Soviet Union and adjacent areas in northeast China. But this time scientists were baffled. 

They found that the 1977 H1N1 virus was closely related to the H1N1 human influenza viruses circulating in 1949-1950. 

As is being seen in the novel coronavirus, viruses evolve continuously and accumulate mutations over time. Detailed genomic studies thus allow researchers to not only trace the journey of the virus, but also determine how long it may have been in circulation. 

In a research paper published in the journal Nature in 1978, a team of scientists from The City University of New York found that the 1977 virus was genomically similar to the 1950 virus — almost as though the viral evolution had been frozen in time. 

It may be possible for an accidental mutation to develop that is similar to a variant from the past — but the scientists deemed it was not plausible to speculate that such back mutations accidentally produced a strain so similar to something that circulated 27 years ago. 

Another team from the University of Giessen in Germany came to a similar conclusion in an independent study published the same year in the journal Virology. 

“The data obtained are compatible with the view that an H1N1 strain from 1950 survived somewhere with few mutations for 27 years and then reappeared as a virus pathogenic for man,” the researchers wrote in the study. 

A 1978 study by researchers from the Chinese Academy of Medical Sciences showed that the virus primarily affected those below the age of 20 — giving support to the theory that those above that age had already been exposed to the same virus before, and thus had developed immunity. 

In the same paper, however, the team dismissed the lab leak theory in one sentence, stating that none of the “laboratories concerned” had been storing or working with the H1N1 for a long time. 

Several scientific papers cite the work of Russian virologist W.I.B. Beveridge in 1978 that also dismissed the notion of a lab leak. ThePrint was unable to access this publication. 

Why the theory was not pursued

US researchers suggest that the Western scientists didn’t pursue the lab leak theory at the time for several reasons. These include tensions between the US and the USSR amid the Cold War.

The WHO’s Global Influenza Surveillance and Response System (GISRS) — a network of laboratories to monitor the spread of influenza — was established in 1952 to conduct global influenza surveillance. 

Russia joined this network only in 1971.   

In a 2014 report titled “Laboratory Escapes and ‘Self-fulfilling prophecy’ Epidemics”, Martin Furmanski, affiliated with the Scientists’ Working Group on Chemical and Biologic Weapons Center for Arms Control and Nonproliferation, wrote that Western scientists at the time did not want to offend their Russian and Chinese counterparts, as their cooperation was important for such a global networks to track influenza to be successful. 

According to Furmanski, Russia and China’s move to actually report the outbreak was considered to be an early sign of their cooperation in the network. 

So, Western researchers began to present alternative theories — one of these being that the virus may have been lying dormant in an unidentified animal. 

However, these came to be discredited. Studies in chickens, for example, showed that although the virus may cause transient infection in four-day-old chickens, the 1977 H1N1 virus was not found in chickens over a month old. 

A 2006 study suggested that influenza virus shed by migratory birds was left frozen in Siberian lakes — and the thawing of these lakes may have brought an old virus back into circulation.  

But, in 2008, researchers at the University of Arizona showed that the viral samples in the 2006 study had been contaminated by other samples in the lab.

Eventually, no evidence to support natural latency of the virus emerged. By 2008, the laboratory leak theory became largely accepted among the scientific community. 

A 2015 paper by Michelle Rozo and Gigi Kwik Gronvall at UPMC Center for Health Security noted how the 1977 outbreak had become a “cautionary tale” in the arguments against gain-of-function research — which involves enhancing the properties of a virus in a way that makes it more infectious or dangerous, so as to preempt potential pandemics and prepare vaccines or treatments. 

Such research had come under the scanner in the US after a 2012 study modified an avian flu virus to show how it may have transmitted into humans. 

To this date, speculations around the 1977 outbreak continue. Rozo and Gronvall, for example, propose in their paper that the Russians may have deliberately leaked the virus as a form of “biowarfare”, or that vaccine trials may have caused the virus to leak out. 

While the exact sequence of incidents that led to the pandemic is not understood, the outbreak is largely attributed to an experimental oversight.

(Edited by Sunanda Ranjan)