New Delhi, April 24 -- A single-dose dengue vaccine developed by Brazil's Butantan Institute demonstrated 65% efficacy against symptomatic dengue over five years of follow-up and showed meaningful protection even in people who had never previously been infected - potentially clearing a critical barrier that has beset dengue vaccine attempt to date. The findings, published in Nature Medicine in March, hold promise for a disease that leads to thousands of deaths worldwide. Dengue infected more people in 2024 than in any year on record, with WHO receiving reports of 14.4 million cases - including more than 52,000 severe cases and 11,201 deaths - across more than 100 countries. India is among nations badly hit by the disease, with four serotype...