Compatibility summary
Your Switzerland plug may fit in Vietnam outlets, as both use at least one common plug type.
Plug comparison
Switzerland plug types: C J
Vietnam plug types: A C F
Both countries share at least one plug type (C J and A C F), so some plugs may work without an adapter. Check your appliance.
Voltage comparison
Switzerland: 230V, 50Hz
Vietnam: 220V, 50Hz
Voltage difference is within a range many devices tolerate; check your appliance label.