The study underscores the need for equitable access to vaccines, effective drugs, and mosquito-control efforts, the authors say.
The vaccine is the first of its kind against chikungunya, a high-burden disease that is spreading to new areas.
Several of the El Nino health risks are due to water contamination, either from flooding or drought. Malnutrition due to food insecurity was the top threat.
ACIP topics include RSV, flu, polio, mpox, meningococcal, and COVID-19 vaccines.
A single dose of the vaccine candidate triggered neutralizing antibody production in 98.9% of recipients 28 days later.
Dengue in the Americas is outpacing 2022 activity by 12%, and chikungunya is also on the rise.
PAHO officials say they are seeing changes in the timing and magnitude of cases that are likely related to the effects of climate change and unplanned urbanization.
Separate WHO reports describe widening dengue and chikungunya activity in the Americas and the expansion of cholera outbreaks to four more countries.
Cases are surging, especially in Paraguay and Brazil, with conditions ripe for further spread and health systems weakened by the pandemic and other demands.
Since the outbreak began in October 2022, officials have reported 71,748 suspected cases of the mosquito-borne disease.
