Today during general remarks, Director-General Tedros Adhanom Ghebreyesus, PhD, of the World Health Organization (WHO) said the ongoing Ebola outbreak in the Democratic Republic of Congo is on track to become the world’s largest, outpacing the West African outbreak of 2014 to 2016, which saw more than 11,000 people die.

“The outbreak had a big head start, it is still way ahead of us, and we are playing catch-up,” Tedros said. 

As of today, the WHO reports 4,449 confirmed cases, with 2,061 deaths across five provinces and 53 health zones. Ninety percent of cases are from Ituri province, which also accounts for 80% of all deaths. 

Most deaths are happening in the community, Tedros explained, which means there are still unknown transmission chains and incomplete contact follow-up. 

“With partners, we are mapping and pooling resources to strengthen community-based surveillance, to bring every suspected case into care and reach the 95% contact-tracing target needed to interrupt transmission—today we are at around 80%,” Tedros said. He also said the WHO was working to train and place more healthcare workers in the area, as Ebola patients need providers at a 3:1 ratio. 

WHO moves forward on Ervebo trial 

Tedros said the WHO is moving forward with a phase 3 trial of the Ervebo vaccine, which targets the Ebola Zaire strain, and not the Bundibugyo strain in circulation. Two recent animal studies showed cross-protection of Ervebo on Bundibugyo virus in animals. 

“We do not know whether this vaccine is efficacious against Bundibugyo disease in humans,” Tedros said. “The phase 3 trial is the best way to ensure a safe and effective vaccine is available as soon as possible for this and future outbreaks.”

Experts considered the 2024-25 influenza season severe, the most serious since the 2017-18 season. Vaccination against flu protected US adults and children from hospitalization and needing outpatient medical care, according to a paper published last week in Open Forum Infectious Diseases. 

“These findings support influenza vaccination as an important tool to reduce influenza-associated morbidity and mortality across the lifespan,” wrote the authors, led by researchers at the Centers for Disease Control and Prevention (CDC).

43% to 54% vaccine effectiveness

Using a test-negative, case-control design, scientists examined the electronic records of patients who visited one of seven Virtual SARS-CoV-2, Influenza, and Other (VISION) sites to understand how well the flu vaccine prevented hospitalizations and emergency department and urgent care clinics (ED/UC) from October 2024 to April 2025. They looked at healthcare interactions in children ages 6 months to 17 years, as well as adults. 

The data included 5,764 pediatric hospitalizations and 102,854 ED/UC visits. Among adults, 76,072 were hospitalized, and 233,411 sought outpatient treatment. 

In total, 17% of children and 28.2% of adults were vaccinated. For children, the vaccine was 51% effective against flu-related hospital stays and 54% effective against ED/UC visits. Vaccine effectiveness in adults was 43% against hospitalization and 49% against ED/UC visits. 

These findings support influenza vaccination as an important tool to reduce influenza-associated morbidity and mortality across the lifespan.

The researchers found that vaccines were most effective during the first two months following vaccination, after which protection waned. 

“Seasonal influenza vaccination provided protection against influenza-associated hospitalizations and ED/UC encounters among US children and adults during the 2024-25 season,” the authors wrote. “Protection was also observed against critical illness, including ICU [intensive care unit] admissions in children and ICU admissions and deaths in adults.”  

Administering the monoclonal antibody nirsevimab to infants in primary care reduced outpatient antibiotic prescribing for respiratory infections, according to a study by researchers with the Children's Hospital of Philadelphia (CHOP).

Respiratory syncytial virus (RSV) is the most common cause of hospitalization in children younger than 1 year old and is estimated to be responsible for one out of every three hospitalizations for acute respiratory tract infection (ARTI). It's also a common reason for antibiotic use: Roughly half of children hospitalized with RSV, and nearly one-third of those who show up at outpatient clinics with RSV, receive an antibiotic.

Approved by the Food and Drug Administration in 2023, nirsevimab (Beyfortus) provides infants with immediate, short-term protection against RSV and has been shown to prevent RSV-associated hospitalizations. To evaluate its effectiveness in reducing antibiotic use for ARTIs, the researchers analyzed electronic health record data from 32 practices in the CHOP Primary Care Network. Using target trial emulation, they compared outpatient and inpatient antibiotic prescribing in infants younger than 8 months with ARTIs who received nirsevimab with those who didn't.

“Because (1) ARTIs are the most common indication for sick visits in infants, (2) antibiotic prescribing for viral ARTIs, including those caused by RSV, is common, and (3) RSV infections can either mimic or lead to bacterial illnesses (eg, acute otitis media [ear infection] and pneumonia), nirsevimab use might indirectly reduce safely avoidable antibiotic exposure in this population,” the study authors wrote last week in Clinical Infectious Diseases.

14% reduction in outpatient antibiotics for ARTIs

Among the 15,341 infants (average age, 3.5 month; 48.7% female) who were eligible for inclusion, 7,413 received nirsevimab; both groups were similar in terms of measured characteristics, including gestational age, complex chronic conditions, and insurance coverage. Compared with no treatment, nirsevimab administration led to a 14.4% reduction in antibiotic prescribing for outpatient ARTIs, a 40.3% reduction in antibiotics for outpatient bronchiolitis, and 69.4% reduction in antibiotics for RSV-related hospitalizations.

"Although the primary purpose of nirsevimab is to prevent RSV-associated hospitalizations, this study demonstrates a clinically meaningful reduction in RSV-associated antibiotic use, revealing the additional impact of nirsevimab as an important tool for antibiotic stewardship," the authors wrote.