The movie
Things to Come had the first Sci Fi Zombies in the passive victims of "wandering sickness." Who as they died wandered around like sleepwalkers baring plague.
In this Q6 world wandering sickness broke out in Southern Germany in 1939 (researchers have suggested NAZI germ warfare in spite of Hitler disliking those types of weapons). By 1943, Europe outside of Ireland, Iceland, the Orkneys, the Shetlands, the Isle of Man and the
Faroes, is a no-go zone.
The Arab lands are in the process of a full collapse as is the USSR. The Sahara has proved a barrier. Iran, aided by the US and the remnants of the European powers is blocking eastward spread of the plague in the South. So far the vast distances of Siberia have shielded the Far East and India. No one thinks that the quarantine is permanent. Japan, China, India, Ireland, Canada, Iran, New Zealand, and the USA, are in an unstable forced alliance to stop the plague,
Most of this world is TL6, although, since it is WWII, TL7 prototypes are commonplace.