In a chikungunya genotype shift, detection of ECSA in at least 4 countries is concerning, because cocirculation enhances the risk of adaptation.
Agency officials say their analysis indicates the benefits of the vaccine, which contains a weakened form of the chikungunya virus, do not outweigh the risks.
The CDC reported five more influenza-associated pediatric deaths, bringing the total for the 2024-25 flu season to 275.
Rising temperatures, longer summers, milder winters, and changing rainfall patterns are creating more favorable conditions for mosquito populations.
Officials have confirmed five Oropouche virus-related deaths this year, all in Brazil.
France has now reported 63 local chikungunya cases from 16 different administrative units.
The CDC's latest chikungunya travel advisory is for a hot spot in China's Guangdong province.
The WHO said B, C, and D subtypes cause 1.3 million deaths each year and that hepatitis D is now classified as carcinogenic to humans, alongside B and C.
WHO experts are seeing the same chikungunya warning signs that occurred two decades ago, when the virus swept across Indian Ocean countries.
Italy and France are now reporting local chikungunya cases, and 3 countries have confirmed local dengue infections.
