No. Lupus is not contagious. There is no increase in the frequency of the disease in the spouses and/or in the acquaintances of lupus patients. In practice, there are therefore no precautionary measures to be taken.

Infectious agents can act on the immune system, but cannot transmit lupus.

A lot of work is underway to try to understand how the infectious environment (especially viruses) can act on the immune system and possibly facilitate the onset of the disease.

Indeed, some factors probably have a role in lupus and other autoimmune diseases, but the agent, even if it were transmissible, would not be sufficient to cause lupus on its own.