To meet the challenge for efficient, high quality and sustainable care, health systems in developed and increasingly in developing countries require extended communication and cooperation between all principals involved in citizen's care. The challenge also concerns supporting information systems, which demand interoperation with public health, bioinformatics, genomics, administrative, governmental, and other sources of data. The paper describes an architecture development methodology for modeling the integration between clinical and public health information systems that harmonizes existent standardized modeling approaches and integrates HL7 domain knowledge. An integration-architecture for information sharing between public health surveillance and clinical information systems is derived demonstrating the feasibility of the proposed methodology. Predominantly, a harmonized process for analysis, design, implementation and maintenance of semantically interoperable information systems based on formal grammars is discussed in some detail.