Jag tror att filmen du tänker på är Virus , även känd som < em> Reckoning Day från 1980.
Från IMDb-synopsis:
A film that describes the development of a deadly Virus weapons system by the USA Military during the height of the Cold War epoch during the early 1980's. A small group of multinational scientists stuck in the Antarctic learn to survive after a human engineered virus knocks out most of earth's population... ...Only about 800 people in the entire world survive as General Rankin activates the ARS which is set off by an earthquake in the capital Washington and not any Soviet attack, thus blasting the entire world with Nuclear Armaggedon as the Soviets respond with their nukes, finishing off what is left of the population that managed to survive the Virus.
