Chapter 2: Medical Examination and Vaccination Record
A. Purpose of the Medical Examination and Vaccination Report
The results of the medical examination and vaccination record determine whether an applicant is inadmissible on health-related grounds. The medical examination documentation indicates whether the applicant has either a Class A or Class B medical condition and the vaccination record shows whether the applicant has complied with all vaccination requirements.
B. Class A and B Conditions and Their Impact on Admissibility
Class A and B conditions are defined in HHS regulations.  See 42 CFR 34.
Class A conditions are medical conditions that render a person inadmissible and ineligible for a visa or adjustment of status.  Class A conditions are medical conditions mentioned in INA 212(a)(1)(A). A Class A medical condition is a:
Communicable disease of public health significance per HHS regulation;
Present or past physical or mental disorder with associated harmful behavior or harmful behavior that is likely to recur; and
Drug abuse or addiction.
Class B conditions are defined as physical or mental abnormalities, diseases, or disabilities serious in degree or permanent in nature amounting to a substantial departure from normal well-being.  See 42 CFR 34.2(e). This may be a medical condition that, although not rendering an applicant inadmissible, represents a departure from normal health or well-being that may be significant enough to:
Interfere with the applicant’s ability to care for himself or herself, to attend school, or to work; or
Require extensive medical treatment or institutionalization in the future.
C. Completion of a Medical Examination
When a medical examination is required to determine the applicant’s admissibility, the person must be examined by a physician who is designated to perform this examination.
By statute, any medical officer in the U.S. Public Health Service may conduct the examination. However, this rarely occurs. Most medical examinations are conducted by a physician designated as a civil surgeon by USCIS  See INA 232 and 8 CFR 232. or designated as a panel physician abroad by the U.S. Department of State (DOS). Civil surgeons complete medical examinations for applicants in the United States, while panel physicians complete medical examinations for immigrant visa and refugee applicants seeking immigration benefits from outside the United States.