Everyone who works or lives in Sweden is entitled to social security.
The social security system comprises residence-based insurance providing minimum
guaranteed benefits and earnings-related benefits covering loss of income. The system
covers everyone who is resident or working in Sweden. A person who has his or her
real domicile in Sweden is considered to be residing here.
From europa.eu:
As a general rule, any persons who come to live in Sweden are considered to be
residing in the country if they can be presumed to be intending to stay for more than
one year. Any persons resident in Sweden who leave the country are held to be still
residing in Sweden if their absence can be presumed to be of no more than one year’s
duration.
So if this holds for your wife as well, then she will be covered with you. If she cannot be considerd as a resident (for example she will move later once you've settled down, etc.), then while she visits you she should get an EHIC card from your German insurer, which will provide her basic benefits given she is still secured back in Germany.
Once she has moved permamently and can be considered a resident, she will be covered by the Swedish system. She should register herself at the Försäkringskassan, which can be done using this form. At the end of the form it asks you to enclose various documents. You should include one that proves that your wife's social security insurance has ended in Germany, which would clearly signal her intent to permamentaly move to Sweden.
