High death tolls from the 1918 influenza pandemic likely helped the Nazis gain power in "crucial" German elections, according to new research.
In a staff report published on Monday, researchers from the Federal Reserve Bank of New York found that German regions with higher mortality rates from the virus had a higher vote share for the Nazi Party in the elections of 1932 and 1933.
Using regional data on fatalities and historical voting figures, the study found that the share of votes won by the Nazis was higher where a greater share of the population had died during the pandemic.
Around 287,000 people died of influenza in Germany between 1918 and 1920, according to the research.
The study analyzed the link between death rates and other "extremist" parties, but referred to the Nazis as the "clear party of the extreme right."
While the Nazis benefited from the aftermath of the outbreak, extreme left parties, such as the Communist Party, saw their vote share decrease where the pandemic had caused more deaths.
Kristian Blickle, an economist at the bank's Financial Intermediation Function and the author of the report, said the change in demographic caused by the pandemic, coupled with a historical tendency for societies to blame disease outbreaks on foreigners, may have increased support for extremist right-wing politicians.
"The particular strain of influenza that raged in 1918 to 1920 largely affected younger people and thereby reshaped demographics," he said. "Regions most heavily affected lost a relatively larger share of their youth, which compounded the effects of the war. This may have changed the development of societal attitudes going forward."
"Moreover, given the virus' perceived foreign origins, it may have fostered a resentment of foreigners who were seen as responsible for the pandemic," he added.
Blickle said the vote share won by right-wing extremists was stronger in regions that had historically blamed minorities for medieval plagues, which may have led to those communities gravitating toward parties aligned with anti-minority sentiment.
According to the report, the link between flu fatalities and right-wing support was seen even when cities and regions were controlled for ethnic and religious makeup, unemployment, previous right-wing voting and other characteristics that could be assumed to drive extremist voting.
It was also noted that the link between influenza mortality and extremist voting was unique to the pandemic — higher mortality rates from more common illnesses like tuberculosis did not drive a similar trend.
"Tuberculosis was still rampant and a cause of death for many people during and immediately following the first world war," Blickle said. "In fact, it killed a similar number of people as influenza in 1918. However, mortality from tuberculosis was a well-established part of life in the early twentieth century."
Areas where the pandemic had a higher death toll also saw lower public spending per capita in the decade following the outbreak, which in turn contributed to extremist voting.
"Clearly, austerity has an influence on extremism even in the face of the influenza pandemic," the report said. "However, it is also evident that changes in regional spending are not the only channel through which influenza mortality affects voting behaviour."
While Blickle noted the correlation between influenza fatalities and extremist voting, he emphasized the data analyzed in the report had been collected from various sources, which had created "a number of econometric challenges."
"Nevertheless, the study offers a novel contribution to the discussion surrounding the long-term effects of pandemics," he said.
The report's findings also raise questions around the potential political fallout from the current pandemic. Blickle noted that it was important for the social consequences of past pandemics to be studied as the effects of Covid-19 become increasingly pronounced.
Reports of xenophobia toward people of Asian descent have been on the rise, mirroring the pattern outlined in Blickle's research.
More than 30% of Americans have witnessed someone blaming Asian people for the coronavirus pandemic, according to NBC News, while a surge in attacks on Asian students has reportedly occurred across Europe, North America and Australia.
Reports of xenophobia are also on the rise in China, where "foreigners" have been falsely accused of perpetuating the spread of coronavirus in the country.
The new strain of coronavirus is widely thought to have originated in the Chinese city of Wuhan.
Research from British thinktank the Royal United Services Institute has warned that far-right groups and individuals are exploiting the Covid-19 crisis by "promoting disinformation and conspiracy theories to enhance their anti-immigrant or anti-government agendas and attract a new range of followers."
Speaking to CNBC's "Squawk Box Europe" in April, Tina Fordham, head of global political strategy at Avonhurst, said she was concerned that the pandemic could see a fresh emergence of support for extreme nationalist ideologies in Europe.
"The risk here is really a return to populism, which a few years ago was something we were all very concerned about," she said. "And that focus on a national self-interest is going to pave the way for the return of the (Matteo) Salvinis and others who are waiting in the wings for this."
However, Pushan Dutt, professor of economics and political science at INSEAD, told CNBC in an interview that he did not believe the pandemic would push voters toward extreme politics.
"I think the first thing people thought about was technocratic and competent leadership," he said. "And I think they're moving away from these populist politicians, whether they're coming in from the left or coming in from the right."