Pandemiology Watch (January 14-20, 2026)
MEASLES
US.
According to CIDRAP on January 20, 2026, South Carolina reported 212 new measles cases, bringing the total to 646 since the outbreak began in October, of which 563 were unvaccinated. Officials said the outbreak is centered in Spartanburg County, with cases reported in elementary and secondary schools as well as two universities. Currently, 538 people are in quarantine and 33 in isolation. The outbreak is now the largest in the United States and may surpass last year’s West Texas outbreak with 762 cases. In Washington state, three cases linked to the South Carolina outbreak have been confirmed in unvaccinated siblings, marking the first measles cases there since 2023. Health authorities say the US risks losing its measles elimination status.
A recent U.S. study, published in JAMA on January 14, 2026, found that the number of children receiving nonmedical exemptions from school vaccinations (e.g., personal or religious reasons) has increased significantly in many counties. This rise in exemptions reduces community vaccination coverage and may increase the risk of outbreaks of diseases like measles. The study analyzed county-level exemption data from 2010 to 2024, showing that nonmedical exemptions rose after COVID-19, while medical exemptions remained relatively stable. In Spartanburg County, South Carolina, nearly 8% of children opted out of school-required vaccines, and multiple cases in North Carolina have been linked to travel from Spartanburg, according to CNN on January 14, 2026. Health officials urge parents to vaccinate children to prevent further spread.
As of January 14, 2026, the United States has reported 171 new measles cases in 2026, according to the Center for Disease Control. In 2026, the age group 5-19 accounts for 103 of the cases (60%), and children under 5 years account for 42 of the cases (25%). Of the cases reported in 2026, 95% were unvaccinated or had an unknown vaccination status. A total of 2,413 measles cases and three deaths have been reported to date.
Canada.
As of January 19, 2026, Canada has reported 17 new measles cases in 2026, according to the Public Health Agency of Canada. In 2026, 14 of the cases occurred in children (83%). Alberta accounts for 7 of the cases (41%), and Manitoba accounts for 6 of the cases (35%) reported so far in 2026. All 17 cases reported in 2026 were unvaccinated, and none required hospitalization. A total of 5,453 measles cases and two deaths have been reported to date.
MPOX
According to the Bangkok Post on January 19, 2026, Thailand has recorded about 1,000 mpox cases since the disease first emerged in the country in 2022, with Bangkok reporting the highest number of infections. About 97% of cases have occurred in men, and most have been linked to local transmission, with no direct travel to endemic countries reported
H5N1
U.S.
As of January 20, 2026, the Centers for Disease Control and Prevention reports has not reported any cases of person-to-person transmission of H5N1 in the United States. The total remains at 71 confirmed human cases and two deaths.
Marburg virus
On January 6, 2026, Ethiopia’s Ministry of Health announced that no new Marburg virus disease cases had been detected in the past 21 days. There have still been no new cases since then.
Rift Valley Fever
Senegal.
According to CIDRAP on January 14, 2026, the Rift Valley fever outbreak in Senegal, which began in September 2025, has been declared over by local health authorities after no further active cases were identified.
POLIO
Updates on polio activity will be put on pause as there have been few new developments in ongoing outbreaks. Updates will resume once there are significant changes in polio activity.