Travel to Vietnam can be considered as safe. The biggest risk is probably traffic accidents, especially in Ho Chi Minh City and Hanoi. Be extremely careful, especially when crossing busy streets!
Malaria risk for Quy Nhon, Ho Chi Minh City and Hanoi may be considered as negligible.
Find more information on travel health on the website of the UK National Travel Health Network and Centre
The US Department of State classifies Vietnam at the lowest Travel Alert Level 1 ("exercise normal precautions")