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Increased 30-day Mortality Risk in Coronavirus Disease 2019 Compared to Seasonal Influenza
From Korea, a nationwide, population-based cohort study that utilized the National Health Insurance claim database, including individuals newly diagnosed with COVID-19 or influenza between July 2022 and December 2023. The primary outcome was 30-day all-cause mortality. A total of 12,802,169 patients with COVID-19 and 2,888,777 patients with influenza were analyzed. COVID-19 was associated with significantly higher 30-day all-cause mortality compared with influenza (adjusted odds ratio [aOR], 1.76; 95% CI, 1.60–1.94). This elevated risk remained consistent across most subgroups defined by age, sex, healthcare utilization, and comorbidities. Particularly higher risks were observed among adults aged 18–64 years (aOR, 2.93), hospitalized patients (aOR, 2.55), and those with myocardial infarction (aOR, 2.24).
Nirsevimab vs RSVpreF Vaccine for Respiratory Syncytial Virus–Related Hospitalization in Newborns
This population-based cohort study used data from the French National Health Data System. Maternal vaccination with the RSVpreF vaccine occurred during 32 to 36 weeks’ gestation among infants born in mainland France between September 1 and December 31, 2024. Passive infant immunization with nirsevimab occurred prior to hospital discharge. Infants were matched 1:1 by maternity ward discharge date, sex, gestational age, and region. Follow-up ended at the time of RSV hospitalization or death or on February 28, 2025. A total of 42,560 infants (mean age, 3.7 [SD, 1.4] days; 51.7% male) were included in the study (21 280 per group) with a median follow-up of 84 days (IQR, 70-99 days). Of the 481 hospitalizations for RSV-associated lower respiratory tract infection, 212 (44.1%) occurred in the nirsevimab group vs 269 (55.9%) in the RSVpreF vaccine group (between-group difference, −11.8% [95% CI, −18.1% to −5.5%]). Compared with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with a lower risk of hospitalization for RSV-associated lower respiratory tract infection (adjusted HR, 0.74 [95% CI, 0.61 to 0.88]). Compared with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with a lower risk of severe outcomes, including PICU admission (adjusted HR, 0.58 [95% CI, 0.42 to 0.80]), requiring ventilator support (adjusted HR, 0.57 [95% CI, 0.40 to 0.81]), or requiring oxygen therapy (adjusted HR, 0.56 [95% CI, 0.38 to 0.81]). The results were consistent across subgroups and in the sensitivity analyses.
Association Between COVID-19 Vaccine Immunogenicity and Protection against Infection and Severe Disease in Clinically Vulnerable Patient Populations: A Systematic Review and Meta-analysis of Observational Studies
A random effects meta-analysis model was used to pool relative risks of COVID-19 post vaccination infection (BTI) , hospitalization, and death. Unadjusted data were used for the primary analysis due to the lack of adjusted data available in individual studies. They identified 3,305 articles, of which 45 observational studies were included in the review. Negative antibody response following COVID-19 vaccination was associated with higher risks of post vaccination infection’ (PVI) (Relative Risk (RR), 1.82 (1.45–2.29), p < 0.01, I2 = 84.03%), COVID-19-related hospitalization (RR, 5.88 (4.08–8.47), p <0.01, I2 = 25.59%) and death (RR, 3.66 (1.87–7.15), p < 0.01), I2 = 0%). Lack of T-cell response was associated with a higher risk of post vaccination infection’ (PVI)v(RR, 2.08 (1.08–4.04), p 0.03, I2 = 65.99). Using the Newcastle–Ottawa Quality Assessment Scale, 5 (11%) studies were of good quality, 2 (7%) of fair quality, and 37 (82%) of poor quality.
The Effect of Remdesivir and Nirmatrelvir/Ritonavir on Mortality in Patients Hospitalized with COVID-19 During the Omicron Era: An Emulated Target Trial
These are the results of a retrospective population-based cohort study designed as an emulated target trial. Patients were included from six acute care hospitals in Stockholm, Sweden, during the Omicron era. Among 4,016 included patients, 771 (19%) received antiviral treatment. Overall mortality was 9.1% (n = 365) at 30 days and 13.8% (n = 554) at 90 days. The adjusted risk ratio (aRR) of antiviral treatment was 0.80 (95% CI, 0.62–1.01) for 30-day mortality and 0.78 (95% CI, 0.63–0.97) for 90-day mortality. The treatment effect was greater in unvaccinated individuals without previous confirmed infection (aRR, 0.38 [95% CI, 0.18–0.67] vs. aRR, 0.95 [0.64–1.39] in recently vaccinated individuals).
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