Infectious Disease Alert – June 1, 2025

Measles Outbreaks in the United States

Several measles outbreaks have been active in the United States, with more than 1,000 cases reported already in 2025. Most outbreaks begin as unvaccinated individuals in the United States come into contact with an infected individual who has recently arrived after international travel. Vaccination is effective, but current U.S. vaccine coverage rates are below the 95% rate considered necessary to provide herd immunity.

Staphylococcus aureus Endocarditis: A Selection of Just-Published Studies

A selection of reports published in the last two months cover microbiologic diagnosis and management issues.

Baloxavir Prevents Household Transmission of Influenza

Treatment with a single dose of baloxavir led to an adjusted relative risk reduction of 29% in household transmission of influenza compared to placebo. There was no significant difference in safety signals between baloxavir and placebo.

Updated Recommendations for Drug-Susceptible and Drug-Resistant Tuberculosis

The authors provide an update of recommendations for the treatment of tuberculosis, including cases with drug resistance. The recommendations include the use of newer drugs that have undergone clinical trials and shorter durations of therapy.

Restricting Remdesivir in an Immune Era: No Harm, Big Savings

A quasi-experimental, eight-hospital, pre-post restriction of remdesivir to only symptomatic, oxygen-requiring, immunocompromised adults during July 2023 to June 2024 led to a 90% reduction in remdesivir use (37.7% to 4.1%) without any increase in 14- or 28-day all-cause mortality, 30-day readmission, or hospital length of stay. Medium- and high-risk covariate models confirmed no mortality signal, while an intriguing rise in intensive care unit admission and mechanical ventilation use among the few post-intervention recipients was most consistent with residual confounding and confounding by indication (i.e., the sickest patients being channeled to receive therapy). In an era of widespread hybrid immunity from Omicron-descended variants, broad remdesivir formulary restriction can be implemented safely and can yield substantial cost savings without compromising outcomes.

Infectious Disease Updates

Mpox Accelerates in Africa; Why Does Colonization Become Active C. difficile? Avian Influenza in Felines Exposed to Dairy Workers