Measles cases in U.S. by March 31? is a closed prediction market event on Polymarket with 9 markets, $434.5K total volume, and N/A in liquidity. Key markets: Will there be at least 1600 measles cases in the U.S. by March 31, 2026?; Will there be at least 1400 measles cases in the U.S. by March 31, 2026?; Will there be at least 1450 measles cases in the U.S. by March 31, 2026?.