Thanks for posting on HCM,
There are two effective types:
- Ty21a, which is a live vaccine
- Vi capsular polysaccharide vaccine, which is an injectable subunit vaccine
Ty21a is licensed for use from age six years and older. Boosters are recommended annually. The Vi capsular polysaccharide vaccine is licensed for use from age two years and old, and boosters are required every three years.
The injectable form can be administered either subcutaneously (under the skin) or intramuscularly and either way will not be painful. If oral route is available you could take that option as it will of course be completely painless but your son has to be above six.
Hope this helps