The average infantryman in the South Pacific during World War II saw about 40 days of combat in four years. The average infantryman in Vietnam saw about 240 days of combat in one year thanks to the mobility of the helicopter. One out of every 10 Americans who served in Vietnam was a casualty. 58,148 were killed and 304,000 wounded out of 2.7 million who served. Although the percent that died is similar to other wars, amputations or crippling wounds were 300 percent higher than in World War II. 75,000 Vietnam veterans are severely disabled. - Vietnam War Facts, Stats and Myths
It is remarkable that 10% of soldiers who served in the war were casualties. This number must contain soldiers who were not serving on the front lines, but as engineers, logistics, cooks, and other roles. This lead me to wonder what the casualty rates were like for soldiers serving as front-line troops, particular those serving in the hotter areas of the conflict.
Whatever the rate of being wounded among such men is, divided by the 240 days of combat a year it would likely be very high chance of being wounded every day.