{
  "first": "Bert",                                    // personal data
  "last": "Bloggs",
  "birthdate": -921542400,                            // Time.gm(1940, 10, 19).to_i
  "measures": {                                       // bag of measures, one entry per measure
    "0043": {
      "encounter": 1284854400,                        // Time.gm(2010, 9, 19)
      "vaccination": false
    }
  }
}