The 2024-25 COVID mRNA vaccines targeting JN.1 were highly effective in protecting against hospitalization and death for at least 4 months in a cohort of Danish citizens aged 65 and older by October 1, 2024. The new analysis estimating the vaccine efficacy (VE) of last season’s COVID vaccines was published earlier this week in The Lancet Infectious Diseases. 

In total, 894,560 Danish residents were included in the study, with a median age of 76. By Jan 31, 2025, 820,229 (91.7%) of the participants had received a JN.1 vaccine. Among those without updated JN.1 vaccination (74,331), 278 COVID-19 hospitalizations and 84 deaths were observed during 25.6 million person-days. 

In contrast 197 COVID-19 hospitalizations and 56 deaths in 62.9 million person-days were observed in residents who received Pfizer's Comirnaty (among 728,868 recipients). And 10 COVID-19 hospitalizations and 1 death were observed during 9.2 million person-days in those vaccinated with Moderna's Spikevax vaccine (91,461 recipients).

Protection for at least 4 months 

Vaccine effectiveness (VE) for Comirnaty was calculated at 70.2% (95% confidence interval [CI], 62.0% to 76.6%) against hospitalization and 76.2% (95% CI, 63.4% to 84.5%) against death. VE for Spikevax was 84.9% (95% CI, 70.9% to 92.2%) against hospitalization and 95.8% (95% CI, 69.2% to 99.4%) against death. In general, Spikevax recipients were younger and had fewer comorbidities than people who received Comirnaty.

Regularly updated mRNA vaccines targeting circulating variants remain essential for COVID-19 prevention and control.

"JN.1-adapted mRNA vaccines provide high levels of sustained protection—for at least 4 months—against COVID-19 hospitalisation and death in older adults," the authors concluded. "Regularly updated mRNA vaccines targeting circulating variants remain essential for COVID-19 prevention and control."

Shorter-duration antibiotic courses show similar efficacy for bloodstream infections and reduce the length of hospitals stays compared with longer courses, according to a study published yesterday in eClinical Medicine.

The systematic review and meta-analysis, conducted by researchers from China and Singapore, examined 11 randomized controlled trials published from 2006 through 2025 and involving 5,505 immunocompetent patients with bloodstream infections. Five trials compared the efficacy of 10-day antibiotic regimens for bloodstream infections versus 14-day regimens, 5 compared 7 days versus 14 days, and 1 trial compared 7 days versus 10 days. 

The study authors note that while clinicians may be more inclined to choose longer antibiotic courses for bloodstream infections, recent studies have provided insight into the efficacy of shorter courses. "However, the optimal duration of antibiotic treatment for bacterial bloodstream infections remains a subject of intense debate. There is a lack of clear and definitive guidelines, and clinical practice varies widely," they wrote.

No difference in mortality, treatment failure, hospital readmission

The meta-analysis found little to no difference in mortality (risk ratio [RR], 0.91; 95% confidence interval [CI], 0.79 to 1.05; moderate certainty), treatment failure (RR, 1.08; 95% CI, 0.69 to 1.68; moderate certainty), and relapse rates (RR, 1.15; 95% CI, 0.82 to 1.63; moderate certainty) between shorter- and longer-duration antibiotics. 

Compared with longer-duration antibiotics, shorter-duration antibiotics did not increase hospital readmission (RR, 0.91; 95% CI, 0.75 to 1.1; high certainty) but did reduce the length of hospital stay (mean difference, −3.04 days; 95% CI, −3.9 to −2.18; high certainty). Consistent effects were observed across age-groups and bacterial types.

Very low–certainty evidence showed uncertainty on the question of whether shorter-duration antibiotics decrease any adverse events (RR, 1.0; 95% CI, 0.76 to 1.32) and serious adverse events (RR, 0.67; 95% CI, 0.39 to 1.14) compared with longer-duration antibiotics.

"Our study found that there were probably no differences between shorter-duration and longer-duration antibiotics in mortality, treatment failure, relapse, hospital re-admission and clinical cure, while shorter-duration antibiotics were associated with a shorter hospital stay," the authors concluded. "Therefore, the above findings support the use of shorter-duration antibiotics in the bloodstream infections patient population."

Today in Open Forum Infectious Diseases, researchers from the Democratic Republic of the Congo (DRC) report that 86.7% of survivors of the country's 2020 Ebola outbreak who received advanced therapies experienced long-term health effects. 

For 1 year, the researchers followed up on 750 adults and children infected from April to October 2020. The median patient age was 32 years. The outbreak, the DRC's tenth, was the first in which Ebola patients received drugs such as the monoclonal antibodies REGN-EB3, ansuvimab, and ZMapp and the antiviral medication remdesivir.

Untreated Ebola kills 50% to 90% of those infected. Among survivors, short- and long-term symptoms such as fatigue, bone pain, headaches, abdominal pain, and impaired vision or other eye disorders.

"Although new therapeutic agents improved survival, questions remain about their long-term impact," the investigators wrote. "Research has reported late-onset ocular complications, such as uveitis and neurologic symptoms, even in survivors treated with monoclonal antibodies." Another study showed that antibody levels waned quickly over time, particularly in ansuvimab recipients.

Neurologic, musculoskeletal symptoms 

In total, 86.7% experienced post-Ebola conditions, including neurologic (61.7%), musculoskeletal (49.7%), and general (38.4%) symptoms for at least 38 months. 

These results underscore the need for targeting long-term care to effectively manage post-Ebola sequelae.

At enrollment (median time to baseline visit, 330 days after hospital release), neurologic symptoms were more common in the REGN-EB3 group (hazard ratio [HR], 2.14) than in remdesivir recipients. 

Musculoskeletal symptoms were linked to age (HR, 1.02), ZMapp treatment (HR, 3.17), and hemorrhagic symptoms during infection (HR, 1.64), while ocular sequelae were tied to age (HR, 1.04). Patients who were female, older, had underlying metabolic conditions, or received REGN-EB3 were more likely to have recurrent neurologic and musculoskeletal symptoms. Recurrent ocular symptoms were slightly more common in adults than in children (HR, 1.02).

"Despite improved survival with monoclonal antibody therapy, our findings highlight a high incidence of neurologic sequelae in the REGN-EB3 group, and musculoskeletal in ZMapp group compared to the Remdesivir group, also among older survivors, women and those with comorbidities," the authors wrote. "These results underscore the need for targeting long-term care to effectively manage post-Ebola sequelae."