The primary purpose of the social insurance system in Slovakia is to protect the economically active population in various situations. Insurance is mandatory for all employees. The social insurance system has 5 insurance subsystems that cover various benefits:

• sickness insurance (insurance against loss of income from gainful employment as compensation for temporary incapacity to work, pregnancy, and maternity),
• pension insurance (old-age insurance to provide income in old age and in the event of death, and disability insurance to cover a reduction in the ability to carry out gainful employment due to the insured person’s long-term adverse health condition and in the event of death),
• accident/casualty insurance (insurance covering injury or death resulting from a work-related accident or occupational disease),
• warranty insurance (insurance against the employer's insolvency, to meet the employee's claims, to cover old-age pension savings contributions unpaid by the employer, and to contribute to the basic fund for old-age pension savings contributions),
• unemployment insurance (insurance to cover loss of income from employment due to unemployment)

https://www.researchinslovakia.saia.sk/en/main/work-and-daily-life/social-insurace-and-security/

Social insurance is mandatory for all people working in Slovakia. The institution administrating this insurance is called Sociálna poisťovňa (Social Insurance Institution). The registration into this institution is handled by UNIZA.

Based on the information given to the employer, we will provide you with an identity number and register you as an employee. Should you have an agreement on the delegation of responsibility, both social and health insurance need to be established in the country from which you work for UNIZA.

• If you only work at UNIZA, you have no obligation to the Social Insurance Institution or UNIZA.
• If you have further employment contracts within the EU/EEA/Switzerland
  The confirmed PD A1 form needs to be submitted to the relevant personnel officer (the form is processed at the social security institution in the country, where the future employee has another job) https://europa.eu/youreurope/citizens/work/unemployment-and-benefits/social-security-forms/contact_points_pd_a1.pdf . The processing itself takes circa 2 months.