The Week's Top Stories: Breakthrough COVID, FDA Approvals, and More

The latest CDC numbers show a 5.8% increase in measles cases from week-to-week, bringing the 2026 US total to more than double the amount seen in all of 2025 with 2 months left in the year.

Investigational agent Zelicapavir cut time to complete RSV symptom resolution by up to a week and lowered hospitalization in high-risk adults.

Alejandra Gurtman, MD, discussed the phase 2 data at IDWeek 2026 which showed the investigational 25-valent pneumococcal conjugate vaccine 25vPnC produced serotype 3 antibody levels about 15-fold higher than Prevnar 20 after the booster dose, targeting a serotype still behind 10.6% of invasive pneumococcal disease in US children younger than five years.

In an ECOSPOR III analysis, all-cause hospitalization by week 4 fell to 3.4% with fecal microbiota spores vs 16.1% with placebo in recurrent C difficile infection.

The latest CDC numbers show a 4.0% increase in measles cases from week-to-week, bringing the 2026 US total to 4588 confirmed cases. Ninety-six percent of cases are outbreak-associated.

In the phase 3b ENCORE trial, adding amikacin liposome inhalation suspension (ALIS) to azithromycin and ethambutol significantly improved culture conversion in newly diagnosed MAC lung disease, while treatment-emergent amikacin (2.2%) and macrolide (1.1%) resistance stayed rare. Kevin Winthrop, MD, provides insights around the study.

Oral zelicapavir cut time to complete RSV symptom resolution by up to 1 week in high-risk adults, but it did not meet its primary end point in a phase 2 trial.

In the phase 2 RePreve trial, Lumen Bioscience’s investigational oral biologic LMN-201 plus standard antibiotics achieved global cure in 83.3% of patients with C difficile infection vs 36.4% with placebo, and cut recurrence sixfold (9.1% vs 55.6%) with no drug-related serious adverse events.