Measles masquerading as “just fever” in nearly a third of Tanzanian cases — no rash, no suspicion, worse outcomes, and a diagnosis missed for two months

Summary This prospective case-control study enrolled 258 febrile inpatients and 48 controls at a rural Tanzanian hospital over one year (2023-2024), testing blood by PCR for 35 pathogens, culture, and serology. Measles was the leading pathogen, confirmed in 91 cases (35%) by PCR and/or IgM, yet only 64% were clinically suspected and 62% met WHO clinical criteria, because 27 cases (30%) lacked recorded rash. Measles without rash caused longer hospital stays (5.5 vs 3.3 days; P=.010), lower full recovery (48% vs 75%; P=.016), and higher mortality (7% vs 2%). Laboratory testing detected the outbreak two months before clinical suspicion. Comment: This is a stark reminder that “no rash, no measles” is a dangerous clinical heuristic, especially in populations with darker skin tones, where rash can be harder to visually detect and amid global resurgence and rising population immunity gaps. Small single-site study limits generalizability, and vaccination status wasn’t captured—a major gap. My...