Building the Future of Biodefense

Recommendation: Organizations in Napa County, California, should provide flexible work schedules to support employees making vaccine appointments for themselves or family members. Measles is highly contagious and can quickly spread among unvaccinated individuals in a work environment.

Situation: California confirmed a measles case in an unvaccinated child in Napa County, the county's 1st measles case since 2012. The child recently traveled to South Carolina, where a large measles outbreak is ongoing. No public exposure locations were announced. This is California's 2nd measles case of 2026. The 1st case of the year was detected in San Mateo County (see PHC alert 1/9). [Confidence: Very High]

Recommendation: Informational update only.

Situation: The Africa CDC lifted the Public Health Emergency of Continental Security (PHECS) declaration for mpox in Africa, as announced in this week's briefing. The PHECS, which was declared in August 2024, was lifted due to the sustained decline in cases, reduced mortality, improved testing capacity, and the disease trending towards endemicity in several countries. Across the continent, confirmed mpox cases started to decline following the peak in May 2025. In the past 6 weeks, there was a 90% decrease in confirmed cases, from 1,442 to 140 cases. Overall, there were 224,692 suspected cases, 61,764 confirmed cases, 2,193 suspected deaths, and 297 confirmed deaths across 32 countries from the start of the PHECS declaration, as of week 3 in 2026. Officials cautioned that mpox is not eliminated, and endemic transmission continues in high-burden countries. Country-led preparedness and control measures, as well as expanding access to vaccination, will be prioritized going forward. See PHC alerts on 9/5/2025, 9/4/2025, 8/14/2025, and 8/13/2024 for earlier info. [Confidence: Very High]

Recommendation: Local chikungunya transmission is very rare in the mainland US, with 13 cases detected in Florida and Texas in 2014-15, though it more commonly occurs in some US territories. Organizations in Miami-Dade County, Florida, should reduce mosquito populations at their facilities by eliminating standing water. Employees can prevent mosquito bites by wearing protective clothing, using insect repellent, and eliminating standing water near their homes.

Situation: Florida confirmed the detection of a locally acquired chikungunya case in Miami-Dade County. The individual's symptom onset was in December 2025. This detection is the 1st in the state for 2025, and 2nd in the nation for 2025 after New York detected a suspected locally acquired chikungunya case in October (see PHC alert on 10/15). 328 imported chikungunya cases with symptom onsets in 2025 were reported across Florida, of which 96% reported travel to Cuba, where an outbreak is ongoing. 214 of the imported cases were detected in Miami-Dade County. [Confidence: Very High]

Recommendation: Employees traveling to Colombia should consult their healthcare provider about getting the yellow fever vaccine at least 10 days before departure, and check any domestic vaccination requirements necessary for travel within the country to avoid delays. Organizations should provide flexible work schedules to support employees making vaccine appointments for themselves or family members. Employees can prevent mosquito bites by wearing protective clothing and using insect repellent.

Situation: From 1/1 to 1/20, Colombia reported 14 new yellow fever cases in Tolima, totaling 135 confirmed cases and 53 deaths since 2024. 8 of those cases and 4 of those deaths occurred in the past week (1/14-1/20). Nationally, 155 cases, including 68 deaths, have been recorded since 2024. Media sources reported that recent cases were linked to an outbreak in Chaparral, in southern Tolima. An unspecified number of monkeys died in the same area recently. See PHC alerts on 9/25, 6/17, and 4/17 for earlier info. [Confidence: Very High]