Welcome to the sixth edition of FOI Clinical. Each week, I'll send you a briefing on outbreak news. When something urgent breaks, you'll get an alert the same day.
In this edition
Measles - Seasonal Respiratory Infections - Interim Flu VE - Expanded RSV Vax Approval - Hantavirus in New Mexico - Infant Formula Recall Outside US - Meningitis in the UK
National interest
Measles
As of March 12, 2026, there have been 1,362 confirmed cases of measles this year, up 81 from the week prior. Thirty-one states have reported cases. The largest case totals are in South Carolina, Utah, Florida, and Texas.
Several notable outbreaks are underway. The list below is not comprehensive, but rather a selection of prominent active clusters worth keeping in mind.
- South Carolina: The multi-county outbreak in South Carolina has 997 confirmed cases to date. The outbreak has slowed considerably, with 7 new cases confirmed in the past two weeks.
- Arizona/Utah: The apparent slowdown over the past couple of weeks was a mirage. Cases have shot up in Utah, with more cases reported during the last week in February (44) than in any prior week in the outbreak (data reporting is a few weeks delayed for the state). This brings the total for 2026 to 209 and the outbreak total to 405, meaning more cases have now been reported this year than last year. More than 150 people (nearly 40%) have gone to the emergency department for measles during this outbreak, according to the state's epidemiologist. Exposed locations are listed here. Increasing vaccination rates is proving challenging, particularly in the heavily-affected southwestern part of the state. In contrast, Arizona has not reported any new cases in March, and the total remains at 276 for the outbreak.