Overview

• WHO reports 445,271 suspected and confirmed cases and 155 deaths from 40 countries through September 30, with the Americas leading case counts and confirmed activity in Europe’s French overseas territories.
• The BMJ Global Health model estimates about 14.4 million infections each year long term, projecting roughly 5.1 million at risk in India and a combined 48% of global impact concentrated in India and Brazil.
• Researchers highlight chronic illness as the dominant burden, with about half of symptomatic patients facing prolonged joint pain and the chronic phase accounting for an estimated 54% of total disease impact.
• A Science Advances analysis of 86 outbreaks finds severity is hard to predict, as climate signals where transmission is possible but local conditions and chance drive how large outbreaks become, complicating trial design and preparedness.
• Two vaccines have regulatory approval in limited geographies, while WHO urges stronger surveillance and vector control due to low population immunity, favorable breeding conditions, diagnostic gaps, and increased mobility.