Kinji Fukasaku had hired an American company to do the special effects. When he saw the results he disapproved and stated that he could not use it because it looked too realistic. He would hire a Japanese company to do the work instead. The reason being was to focus on creating evocative and poetic images instead.
It was the most expensive Japanese film made up to that point.
Haruki Kadokawa was the heir to a major publishing empire. He entered the film business in the mid 1970s with some high-profile features. This was to be his big breakthrough in the international market. He tried to ensure its success by casting some U.S. stars and doing major international promotion (under the international title "Virus"). However, the film was a major flop. Although it may have had some special showings in the U.S., it did not receive a general release. It was sold directly to pay television in an edited one hundred eight-minute version.
This film gained some international publicity when a Swedish ship, the M.S. Lindblad Explorer, transporting a production unit to Antartica for location shooting, struck a submerged reef and almost sank. Passengers were rescued by Chilean Navy ships.
While the film is about a Pandemic, Shin'ichi Chiba himself later died from the COVID-19 virus at age 81 in 2021.