English 
Spanish 
Hantavirus in Humans: A Review of Clinical Aspects and Management
Hantavirus infections are part of the broad group of viral haemorrhagic fevers. They are also recognised as a distinct model of an emergent zoonotic infection with a global distribution. Many factors influence their epidemiology and transmission, such as climate, environment, social development, ecology of rodent hosts, and human behaviour in endemic regions. Transmission to humans occurs by exposure to infected rodents in endemic areas; however, Andes hantavirus is unique in that it can be transmitted from person to person. As hantaviruses target endothelial cells, they can affect diverse organ systems; increased vascular permeability is central to pathogenesis. The main clinical syndromes associated with hantaviruses are haemorrhagic fever with renal syndrome (HFRS), which is endemic in Europe and Asia, and hantavirus cardiopulmonary syndrome (HCPS), which is endemic in the Americas. HCPS and HFRS are separate clinical entities, but they share several features and have many overlapping symptoms, signs, and pathogenic alterations. For HCPS in particular, clinical outcomes are highly associated with early clinical suspicion, access to rapid diagnostic testing or algorithms for presumptive diagnosis, and prompt transfer to a facility with critical care units. No specific effective antiviral treatment is available.
Efficacy and Safety of an mRNA Seasonal Influenza Vaccine in Adults
In this phase 3, double-blind, active-controlled trial, authors randomly assigned adults 50 years of age or older to receive trivalent mRNA-1010 (37.5 μg, which includes 12.5 μg of each strain) or a licensed standard-dose comparator. A total of 40,703 participants received mRNA-1010 (20,350 participants) or the standard-dose comparator (20,353 participants); the median follow-up was 181 days (range, 1 to 227). RT-PCR–confirmed, protocol-defined influenza-like illness was observed in 411 of 20,179 recipients of mRNA-1010 (2.0%) and 557 of 20,124 recipients of the standard-dose comparator (2.8%), which corresponds to a relative vaccine efficacy of 26.6% (95% CI, 16.7 to 35.4), thereby meeting the criteria for noninferiority, superiority, and higher-level superiority. In this trial, mRNA-1010 was superior to standard-dose licensed vaccines for prevention of RT-PCR–confirmed, protocol-defined influenza-like illness in adults 50 years of age or older. Solicited adverse reactions were more frequent with mRNA-1010.
Maternal RSV Vaccination, Infant Nirsevimab, or Both: Interim Analysis of a Randomized Trial
These are the results of a prospective, randomized, open-label, phase 4 study at 8 US sites of mother-infant pairs randomized 1:1:1:1 during pregnancy: maternal RSVpreF vaccine alone, maternal RSVpreF vaccine/infant nirsevimab at birth, maternal RSVpreF vaccine/infant nirsevimab at 3 months, or infant nirsevimab alone at birth. In total, 181 mothers were enrolled. Both products alone and in combination were safe. No related serious adverse events were observed in mothers or infants. Nirsevimab was well tolerated, and all local and systemic reactogenicity was mild to moderate in severity. RSVpreF vaccination boosted maternal RSV-A nAb titers 17.35-fold at the time of delivery, and titers were durable through 3 months postdelivery. The geometric mean transfer ratio of RSV-A nAbs was higher than 1.3 and similar across groups. RSV nAbs were highly elevated in infants at 6 weeks and 3 months, irrespective of group, with modest differences in waning.
Ensitrelvir for Covid-19 Postexposure Prophylaxis in Household Contacts
This double-blind, randomized, placebo-controlled trial randomly assigned persons who were SARS-CoV-2–negative on local diagnostic testing but were household contacts of a patient with Covid-19 (the index patient) to receive either ensitrelvir or placebo within 72 hours after symptom onset in the index patient. The primary end point was Covid-19 (defined by a central laboratory–confirmed positive reverse-transcriptase–polymerase-chain-reaction assay and the presence of ≥1 of 14 prespecified Covid-19 symptoms lasting ≥48 hours) by day 10 in a household contact in the modified intention-to-treat population. The modified intention-to-treat population included 1,030 participants in the ensitrelvir group and 1,011 in the placebo group. The mean age of the participants was 42.4 years. The incidence of Covid-19 was lower in the ensitrelvir group than in the placebo group (2.9% vs. 9.0%; risk ratio, 0.33; 95% confidence interval [CI], 0.22 to 0.49; P<0.001). No Covid-19–related hospitalizations or deaths were reported. Ensitrelvir administered to household contacts of a patient with Covid-19 within 72 hours after symptom onset in the index patient was effective in preventing Covid-19 in the contacts.
Situation Dashboards
World Health Organization (WHO)
Johns Hopkins University (JHU)
COVID-19 in US and Canada
