Do employees of self-employed households also need letters of introduction to apply for health certificates?

Self-employed employees do not need a letter of introduction to apply for health certificates. According to the relevant public information, no letter of introduction is required. Employees of self-employed households only bring their ID cards and two one-inch bareheaded color photos to the centers for disease control and prevention of relevant departments or health institutions approved by the Ministry of Health to undertake preventive health checks and ask the staff about the specific process of handling health certificates.