# How an mRNA vaccine trains your body

> A process map exported from forks.world (https://forks.world). Author: Brian. Source: https://forks.world/p/cmv0kpvp90004jv06d639umxz
> It describes who does what, in what order, and with which technology. Read the plain-language sections first; the JSON at the end is the exact, complete data.

## Summary

- 18 steps across 2 layers
- Persona: You, Your cells, Your immune system
- Technology / systems: The vaccine

## How to read this file

- A process is made of **layers**. The main layer is the top level; any step of kind `subprocess` opens a detail layer with its own lanes and steps.
- **Lanes** are either persona (people/roles) or technology (systems). Each step belongs to one lane; `using` lists tools a person uses for that step.
- Step kinds: `start`, `task`, `decision` (its arrows carry the answer as a label), `subprocess`, `end`.

## How an mRNA vaccine trains your body

Lanes:
- You: person / role (id `body`)
- The vaccine: technology / system (id `vax`)
- Your cells: person / role (id `cell`)
- Your immune system: person / role (id `imm`)

Steps, in the order they run:

1. **Get the injection** [start; You; id `m1`]
   - then Tiny fat bubbles (lipid nanoparticles) carry the mRNA into cells
2. **Tiny fat bubbles (lipid nanoparticles) carry the mRNA into cells** [task; The vaccine; id `m2`]
   - then Cells read the mRNA and build a harmless piece of the virus, the spike
3. **Cells read the mRNA and build a harmless piece of the virus, the spike** [task; Your cells; id `m3`]
   - then Show the spike on the cell surface
4. **Show the spike on the cell surface** [task; Your cells; id `m4`]
   - then Immune cells spot something foreign
5. **Immune cells spot something foreign** [task; Your immune system; id `m5`]
   - then Build antibodies and train T cells
6. **Build antibodies and train T cells** [subprocess; Your immune system; id `m6`], opens the detail layer "Training the immune system"
   - then The mRNA breaks down within days
7. **The mRNA breaks down within days** [task; Your cells; id `m7`]
   - then Memory cells remain
8. **Memory cells remain** [task; Your immune system; id `m8`]
   - then The real virus arrives
9. **The real virus arrives** [task; You; id `m9`]
   - then Do the memory cells recognize it?
10. **Do the memory cells recognize it?** [decision; Your immune system; id `m10`]
   - if "Yes" go to A fast, strong response: a milder illness; if "Partly" go to A smaller response, and boosters update the memory
11. **A fast, strong response: a milder illness** [end; Your immune system; id `m11`]
12. **A smaller response, and boosters update the memory** [end; Your immune system; id `m12`]

```mermaid
flowchart LR
  subgraph l_body["You"]
    n_m1(["Get the injection"])
    n_m9["The real virus arrives"]
  end
  subgraph l_vax["The vaccine"]
    n_m2["Tiny fat bubbles (lipid nanoparticles) carry the mRNA into cells"]
  end
  subgraph l_cell["Your cells"]
    n_m3["Cells read the mRNA and build a harmless piece of the virus, the spike"]
    n_m4["Show the spike on the cell surface"]
    n_m7["The mRNA breaks down within days"]
  end
  subgraph l_imm["Your immune system"]
    n_m5["Immune cells spot something foreign"]
    n_m6[["Build antibodies and train T cells"]]
    n_m8["Memory cells remain"]
    n_m10{"Do the memory cells recognize it?"}
    n_m11(["A fast, strong response: a milder illness"])
    n_m12(["A smaller response, and boosters update the memory"])
  end
  n_m1 --> n_m2
  n_m2 --> n_m3
  n_m3 --> n_m4
  n_m4 --> n_m5
  n_m5 --> n_m6
  n_m6 --> n_m7
  n_m7 --> n_m8
  n_m8 --> n_m9
  n_m9 --> n_m10
  n_m10 -->|"Yes"| n_m11
  n_m10 -->|"Partly"| n_m12
```

### Training the immune system (detail of step "Build antibodies and train T cells")

Lanes:
- Your immune system: person / role (id `imm`)

Steps, in the order they run:

1. **Helper T cells read the spike** [start; Your immune system; id `t1`]
   - then B cells make antibodies
2. **B cells make antibodies** [task; Your immune system; id `t2`]
   - then Killer T cells learn to find infected cells
3. **Killer T cells learn to find infected cells** [task; Your immune system; id `t3`]
   - then Does the response last?
4. **Does the response last?** [decision; Your immune system; id `t4`]
   - if "Yes" go to Long-term memory; if "It fades over time" go to Boosters remind the immune system
5. **Long-term memory** [end; Your immune system; id `t5`]
6. **Boosters remind the immune system** [end; Your immune system; id `t6`]

```mermaid
flowchart LR
  subgraph l_imm["Your immune system"]
    n_t1(["Helper T cells read the spike"])
    n_t2["B cells make antibodies"]
    n_t3["Killer T cells learn to find infected cells"]
    n_t4{"Does the response last?"}
    n_t6(["Boosters remind the immune system"])
    n_t5(["Long-term memory"])
  end
  n_t1 --> n_t2
  n_t2 --> n_t3
  n_t3 --> n_t4
  n_t4 -->|"Yes"| n_t5
  n_t4 -->|"It fades over time"| n_t6
```

## Full data (JSON)

```json
{
  "title": "How an mRNA vaccine trains your body",
  "maps": {
    "m_root": {
      "id": "m_root",
      "lanes": [
        {
          "id": "body",
          "name": "You",
          "type": "person"
        },
        {
          "id": "vax",
          "name": "The vaccine",
          "type": "system"
        },
        {
          "id": "cell",
          "name": "Your cells",
          "type": "person"
        },
        {
          "id": "imm",
          "name": "Your immune system",
          "type": "person"
        }
      ],
      "steps": [
        {
          "id": "m1",
          "kind": "start",
          "lane": "body",
          "next": [
            {
              "to": "m2"
            }
          ],
          "uses": [],
          "label": "Get the injection"
        },
        {
          "id": "m2",
          "kind": "task",
          "lane": "vax",
          "next": [
            {
              "to": "m3"
            }
          ],
          "uses": [],
          "label": "Tiny fat bubbles (lipid nanoparticles) carry the mRNA into cells"
        },
        {
          "id": "m3",
          "kind": "task",
          "lane": "cell",
          "next": [
            {
              "to": "m4"
            }
          ],
          "uses": [],
          "label": "Cells read the mRNA and build a harmless piece of the virus, the spike"
        },
        {
          "id": "m4",
          "kind": "task",
          "lane": "cell",
          "next": [
            {
              "to": "m5"
            }
          ],
          "uses": [],
          "label": "Show the spike on the cell surface"
        },
        {
          "id": "m5",
          "kind": "task",
          "lane": "imm",
          "next": [
            {
              "to": "m6"
            }
          ],
          "uses": [],
          "label": "Immune cells spot something foreign"
        },
        {
          "id": "m6",
          "kind": "subprocess",
          "lane": "imm",
          "next": [
            {
              "to": "m7"
            }
          ],
          "uses": [],
          "child": "m_train",
          "label": "Build antibodies and train T cells"
        },
        {
          "id": "m7",
          "kind": "task",
          "lane": "cell",
          "next": [
            {
              "to": "m8"
            }
          ],
          "uses": [],
          "label": "The mRNA breaks down within days"
        },
        {
          "id": "m8",
          "kind": "task",
          "lane": "imm",
          "next": [
            {
              "to": "m9"
            }
          ],
          "uses": [],
          "label": "Memory cells remain"
        },
        {
          "id": "m9",
          "kind": "task",
          "lane": "body",
          "next": [
            {
              "to": "m10"
            }
          ],
          "uses": [],
          "label": "The real virus arrives"
        },
        {
          "id": "m10",
          "kind": "decision",
          "lane": "imm",
          "next": [
            {
              "to": "m11",
              "label": "Yes"
            },
            {
              "to": "m12",
              "label": "Partly"
            }
          ],
          "uses": [],
          "label": "Do the memory cells recognize it?"
        },
        {
          "id": "m11",
          "kind": "end",
          "lane": "imm",
          "next": [],
          "uses": [],
          "label": "A fast, strong response: a milder illness"
        },
        {
          "id": "m12",
          "kind": "end",
          "lane": "imm",
          "next": [],
          "uses": [],
          "label": "A smaller response, and boosters update the memory"
        }
      ],
      "title": "How an mRNA vaccine trains your body",
      "parent": null
    },
    "m_train": {
      "id": "m_train",
      "lanes": [
        {
          "id": "imm",
          "name": "Your immune system",
          "type": "person"
        }
      ],
      "steps": [
        {
          "id": "t1",
          "kind": "start",
          "lane": "imm",
          "next": [
            {
              "to": "t2"
            }
          ],
          "uses": [],
          "label": "Helper T cells read the spike"
        },
        {
          "id": "t2",
          "kind": "task",
          "lane": "imm",
          "next": [
            {
              "to": "t3"
            }
          ],
          "uses": [],
          "label": "B cells make antibodies"
        },
        {
          "id": "t3",
          "kind": "task",
          "lane": "imm",
          "next": [
            {
              "to": "t4"
            }
          ],
          "uses": [],
          "label": "Killer T cells learn to find infected cells"
        },
        {
          "id": "t4",
          "kind": "decision",
          "lane": "imm",
          "next": [
            {
              "to": "t5",
              "label": "Yes"
            },
            {
              "to": "t6",
              "label": "It fades over time"
            }
          ],
          "uses": [],
          "label": "Does the response last?"
        },
        {
          "id": "t6",
          "kind": "end",
          "lane": "imm",
          "next": [],
          "uses": [],
          "label": "Boosters remind the immune system"
        },
        {
          "id": "t5",
          "kind": "end",
          "lane": "imm",
          "next": [],
          "uses": [],
          "label": "Long-term memory"
        }
      ],
      "title": "Training the immune system",
      "parent": {
        "map": "m_root",
        "step": "m6"
      }
    }
  }
}
```