With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: The use of vitamin A during treatment is recommended to decrease the risk of blindness; however, it does not prevent or cure the disease. A systematic review of trials into its use found no reduction in overall mortality, but two doses (200 000 IU) of vitamin A was shown to reduce mortality for measles in children younger than two years of age. It is unclear if zinc supplementation in children with measles affects outcomes as it has not been sufficiently studied. There are no adequate studies on whether Chinese medicinal herbs are effective.
text_B: Would further studies be needed to show that zinc supplementation affects children with measles?
YES.