What does it mean that Shenzhen's secondary social security is related to the primary social security?

Grade change. The second-level social security in Shenzhen is related to the first-level social security, that is, the treatment of the second-level social security is transferred to the first-level social security, and the grade has changed. Social security in Shenzhen is divided into one, two and three levels, of which the first and second levels are medical units directly under the city and the third level is district-level medical units. The first level of treatment is higher than the second level.