Prompt and Intensive #Antiviral #Chemoprophylaxis in Nursing Home #Influenza #Outbreaks

 

Key Points

-- Question:  Is initiation of antiviral chemoprophylaxis with oseltamivir for 70% or more of eligible nursing home (NH) residents within 2 days of outbreak detection associated with lower 14-day and 30-day mortality and hospitalization compared with a nonintensive approach?

-- Findings:  In this cohort study of 404 influenza outbreaks across 318 NHs with 35 086 resident-trial observations using a sequential target trial emulation and the randomize-censor-weight approach, hospitalization but not death was lower at 14 days post outbreak in NHs that implemented intensive antiviral chemoprophylaxis; 30-day estimates were directionally similar but less precise.

-- Meaning:  Results of this study suggest that clinicians should promptly initiate antiviral chemoprophylaxis in at least 70% of NH residents within 2 days of an influenza outbreak to markedly reduce influenza-related hospitalizations.

Abstract

Importance  

Influenza outbreaks in nursing homes (NHs) can cause high morbidity and mortality. Antiviral chemoprophylaxis with oseltamivir is recommended, yet optimal implementation strategies remain unclear.

Objective  

To examine whether initiating antiviral chemoprophylaxis for 70% or more of eligible NH residents within 2 days of influenza outbreak detection is associated with lower all-cause mortality and hospitalization at 14 and 30 days.

Design, Setting, and Participants  

Retrospective cohort study using a sequential cluster-randomized target trial emulation and randomize-censor-weight approach for influenza outbreaks (September 1, 2018–May 31, 2022) in 12 US NH corporations. Eligibility criteria were age 18 years or older, present on the outbreak-detection day, no antiviral use in the preceding 7 days, no influenza in the past 14 days, and complete baseline data. Residents were followed up until hospitalization or death, an NH discharge to a nonacute-care location, or the end of follow-up. Data were analyzed from February 2023 to January 2026.

Exposures  

Intensive antiviral chemoprophylaxis with oseltamivir (≥70% of eligible residents within 2 days of outbreak detection) or nonintensive antiviral chemoprophylaxis (0% to <70% of eligible residents).

Main Outcomes and Measures  

Outcomes were all-cause death and hospitalizations within 14 and 30 days of outbreak detection. Discrete-time hazard models with pooled logistic regression were applied to estimate weighted risks, risk differences (RDs), and risk ratios (RRs).

Results  

Among 404 outbreaks in 318 NHs, 35 086 resident-trial observations (29 683 residents; median age 78 [IQR, 68- 86] years; 60% women; 81% White; 76% vaccinated) met eligibility criteria. Intensive oseltamivir prophylaxis was randomized to 17 155 observations; 17 931 were randomized to nonintensive care. At 14 days, intensive prophylaxis vs nonintensive yielded an RD of –0.06% (95% CI, −0.73% to 0.93%) and an RR of 0.96 (95% CI, 0.56-1.57) for death, and an RD of –0.96% (95% CI, −1.78% to −0.19%) and an RR of 0.79 (95% CI, 0.64-0.96) for hospitalization. At 30 days, the hospitalization differences persisted but were less precise and there continued to be no difference in death.

Conclusions and Relevance  

Study results suggest that clinicians should initiate antiviral chemoprophylaxis for at least 70% of eligible NH residents within 2 days of outbreak detection to lower risk of hospitalization.

Source: 

Link: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2846967

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#Outbreak of invasive #meningococcal disease, SE #England - #Alert outlines recommended courses of action to manage cases with #infection and #contacts (#UKHSA, March 18 '26)

 

Invasive meningococcal disease: advice for the NHS in England

You may be aware of an evolving situation involving multiple cases of invasive meningococcal disease (IMD) reported among young people linked to the University of Kent and the Canterbury area. 

More information about IMD, signs and symptoms to look out for, and approaches to clinical and public health management are provided in the accompanying Briefing Note. 

The purpose of this CAS Alert is to outline priority steps that primary care and hospital clinicians should consider taking to manage suspected cases, potential contacts of cases, and to reduce the risk of infection spreading. 

Note that this is a rapidly evolving situation and we will update advice as further information emerges.

Epidemiology

-- Between 13 and 17 March 2026, UKHSA identified 20 cases of invasive meningococcal disease in the South East. 

-- Six cases have been confirmed as Neisseria meningitidis group B. 

-- Most cases are students from the University of Kent, Canterbury, and sixth form students from local secondary schools. 

-- At least 10 cases attended Club Chemistry in Canterbury on 5, 6 or 7 March 2026. 

-- The illness has been severe with rapid deterioration, and 2 deaths have occurred.

Management of cases

Infection prevention and control (IPC) and personal protective equipment (PPE)

-- For patients presenting with suspected meningococcal disease, standard infection prevention and control precautions should be followed in line with the National infection prevention and control manual for England (see Appendix 11). 

-- Use appropriate PPE (including Level 2 PPE where clinically indicated) for assessment and management of suspected IMD:

- clinical staff should apply standard respiratory hygiene and infection control measures in routine clinical settings

- wear a fluid resistant surgical facemask for routine care of patients with suspected invasive meningococcal disease

- wear an FFP3 mask or Hood for aerosol-generating procedures performed on patients with suspected invasive meningococcal disease

- continue transmission-based precautions until the patient has been established on antibiotics for at least 24 hours

- no additional or enhanced IPC measures are required beyond those recommended in national guidance

Immediate case management

-- Patients with IMD may present with septicaemia and/or meningitis. 

-- Meningococcal sepsis should be considered in a rapidly deteriorating patient with sepsis even in the absence of a non-blanching rash, which is usually a late sign. 

-- Clinicians should have a high index of suspicion where a young person aged 16 to 30 attends with consistent signs or symptoms.

-- In a community setting, rapid admission to hospital is the highest priority when IMD is suspected. Conveyance to hospital should not be delayed for procurement or administration of antibiotics.

-- In acute settings, patients with sepsis should be managed according to local sepsis guidelines and immediate clinical management should focus on stabilisation (including fluid resuscitation as appropriate) and early engagement with ITU colleagues where necessary.

-- Initial treatment recommendations are as follows (full treatment regimens will be commenced during hospital admission):

- Immediate single dose of IV/IM Ceftriaxone for suspected meningococcal infections (Ceftriaxone, Drugs, BNFC, NICE):

Age/weight / Dose

- adults - dose: 2g stat

- children with body weight 50kg and over or aged 9 years and older: dose 2g stat

- children up to 50kg body weight or aged under 9 years: dose 80 to 100 mg/kg (maximum per dose 4g)

Alternatively, immediate single dose of IV/IM Benzylpenicillin sodium for suspected meningococcal infections where it is not possible to administer Ceftriaxone (Benzylpenicillin sodium, Drugs, BNF, NICE):

Age / Dose

- adults and children aged 10 years or over: dose of 1.2g

- children aged 1 to 9 years: dose of 600mg

- children aged under 1 year: dose of 300mg

Information regarding clinical samples that should be taken for suspected IMD cases and referring meningococcal-positive clinical materials (including isolates, PCR-positive clinical samples and/or DNA extracts, and lysate extracted from Biofire loading syringes) to the National Meningococcal Reference Laboratory, is included in UKHSA national guidance.

Notifying UKHSA

-- All suspected cases of invasive meningococcal disease are statutorily notifiable by registered medical practitioners to the responsible UKHSA health protection team, without waiting for laboratory confirmation.

-- Notify UKHSA by contacting your health protection team.

Management of contacts

Informing contacts

-- Remind any presenting contacts of the signs and symptoms of meningococcal disease (meningitis and septicaemia) and the importance of seeking urgent medical attention if they have symptoms (even if prophylaxis has been taken). 

-- Early detection and treatment can save lives. 

-- The UKHSA South East Health Protection Team have provided warn and inform information to all cases and close contacts and are liaising closely with all educational and other community settings to provide advice.

Providing antibiotic chemoprophylaxis

-- Close contacts of confirmed or probable cases are being identified by UKHSA and require antibiotic prophylaxis. 

-- Timely chemoprophylaxis will prevent cases of disease and will save lives. 

-- Antibiotic prophylaxis should be given as soon as possible (ideally within 24 hours) after the diagnosis of the index case, regardless of vaccination status.

-- Eligibility is defined in national UKHSA and NICE CKS guidance.

-- This includes people who had the following forms of contact during the 7 days before onset of illness in the index case:

- people who have had prolonged close contact with the case in a household-type setting

- intimate kissing or equivalent close contact

- exposure to respiratory secretions (for example, mouth-to-mouth resuscitation)

- other close contacts identified through UKHSA risk assessment

-- In response to this outbreak, a wider group of contacts have been identified as requiring antibiotic prophylaxis on a precautionary basis:

- Students who live on the Canterbury campus at the University of Kent

- Staff who live or work in affected halls of residence blocks on the Canterbury campus at the University of Kent

- Staff members working at Club Chemistry nightclub, Canterbury, and anyone who attended the nightclub as visitors on 5, 6 or 7 of March 2026.

-- Local clinics are offering chemoprophylaxis to contacts in the Canterbury area. If an eligible close contact presents to a healthcare setting (primary or secondary care) and has not already received prophylaxis through UKHSA‑coordinated clinics, this should be prescribed for them.

-- As the outbreak evolves, further groups may be identified that require antibiotic prophylaxis and will be communicated with directly.

-- Where an eligible close contact presents and has not already received prophylaxis please prescribe this as per National guidance.

The first line treatment is ciprofloxacin: 

Ciprofloxacin dosage (for one dose) [note1]

-- All to be given as a single dose:

Age / Dose

- adults and children aged 12 years and over: 500 mg stat

- children aged 5 to 11 years: 250 mg stat

- children aged 1 to 4 years: 125 mg stat

- infants under 1 year [note 2]: 30 mg/kg to a maximum 125mg stat

Note 1. Ciprofloxacin suspension contains 250 mg/5ml.

Note 2. prescribed off-label. 

-- If ciprofloxacin is not suitable, alternatives are listed in the national guidance.

-- Where demand exceeds capacity, ICBs are responsible for ensuring timely access to post‑exposure prophylaxis and vaccination in line with NHS England commissioning guidance.

Advice concerning vaccination

-- Given the severity of the outbreak, and as an additional precautionary measure, a targeted vaccination programme will begin, starting with students that are residents of the Canterbury Campus Halls of Residence at the University of Kent who will be contacted directly. 

-- Precise details of eligibility will be confirmed by UKHSA. UKHSA will continue to assess ongoing risk to other populations and the programme may be extended.

Source: 

Link: https://www.gov.uk/guidance/outbreak-of-invasive-meningococcal-disease-south-east-england

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Latest #update on Clade Ib #mpox - #UKHSA reminds eligible groups to come forward for mpox #vaccination.

 

Last updated 27 October 2025

Latest update

UKHSA is aware of small numbers of locally-acquired cases of clade Ib mpox in the USA, Spain, Italy, the Netherlands and Portugal which have no connection to countries with known clade Ib mpox transmission.  

This suggests there is now community transmission of clade Ib mpox globally. Most of the new cases identified in Europe and the USA have been in gay, bisexual and other men who have sex with men, a population in which clade Ib mpox transmission has not previously been observed.  

Mpox is usually a mild infection, and clade Ia and Ib mpox are no longer classified as a high-consequence infectious disease (HCID). However, it can be severe in some cases. 

The UK has a routine mpox vaccination programme in place for eligible groups, including those who:  

-- have multiple sexual partners  

-- have group sex  

-- visit sex-on-premises venues  

Studies show that the vaccine is around 75 to 80% effective in protecting people against clade II mpox. Although there are no studies on vaccine effectiveness against clade Ib mpox, vaccine protection is expected. A high proportion of people in eligible groups in the UK have already had the vaccine.  

To check if you are eligible or to book an appointment, visit Mpox vaccine - NHS.   

Common symptoms of mpox include: 

-- a skin rash or 

-- pus-filled lesions which can last 2 to 4 weeks. 

-- It can also cause fever, headaches, muscle aches, back pain, low energy and swollen lymph nodes.  

Dr Katy Sinka, Head of Sexually Transmitted Infections at UKHSA:  

''The ways in which we are seeing mpox continue to spread globally is a reminder to come forward for the vaccine, if you are eligible.  

''Although mpox infection is mild for many, it can be severe.  

''Getting vaccinated is a proven effective way to protect yourself against severe disease, so please make sure to get the jab if you are eligible.  

''It is important to remain alert to the risks from this unpleasant illness. Anyone who thinks they may have mpox should contact NHS 111 for advice on what to do.

UKHSA has robust mechanisms in place to investigate suspected cases of mpox of all clade types, irrespective of travel history, with regular updates on confirmed UK cases of mpox.  

UKHSA has today published a technical assessment on mpox to reflect the latest epidemiology. 

Further information about symptoms is available on the NHS website.  

Dr Will Nutland, Director at The Love Tank said:  

''Mpox hasn’t been making headlines for more than a year but these cases show that mpox has not gone away. Routine availability of mpox vaccination, through NHS sexual health clinics, provides an effective way of protecting against mpox. The Love Tank continues to work alongside NHS colleagues to ensure that vaccination programmes continue to reach those who most need them, including in community settings.

Prof. Matt Phillips, President of the British Association for Sexual Health and HIV said:  

''We encourage anyone who is eligible for the vaccine against mpox to talk to their local sexual health clinic and arrange to be vaccinated.   

''These cases are a reminder both that mpox has not gone away, and of the importance of vaccine programmes in reducing the impact of mpox infection.

Richard Angell OBE, Chief Executive, Terrence Higgins Trust said: 

''The last outbreak of mpox hit the gay, bi and other men who have sex with men community disproportionately hard. While it is described as ‘mild’, those who have the mpox rash around their face and body, including in intimate and sensitive areas, will tell you how unpleasant and painful it is.  

''In 2022, we were not prepared for the MPOX outbreak and the tools available were hard to mobilise – this time we have a government-funded vaccine programme available to gay and bi men and it is strongly encouraged for those who have multiple partners, take part in sex parties or visit sex on premises venues.  

''With Winter Pride season soon upon us across Europe, those travelling to these events would be wise to get vaccinated, at least once, if not twice. Those who have had 2 mpox jabs should have protection. Anyone experiencing a rash after sex should seek out a sexual health clinic or call THT Direct on 0808 802 1221.

(...)

Source: United Kingdom Health Security Agency, https://www.gov.uk/government/news/ukhsa-detects-first-case-of-clade-ib-mpox

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Use of #Influenza #Antivirals to Prevent #Transmission

 

Abstract

Influenza antivirals play an important role in the prevention and control of influenza. We reviewed data on the effectiveness of influenza antivirals for reducing influenza transmission. We found that antiviral prophylaxis, whether given pre- or postexposure, has been shown to reduce the risk of symptomatic influenza in a variety of settings and populations. During pandemic responses, antiviral prophylaxis could play an important role, as demonstrated by the use of amantadine in the 1968–1969 influenza A(H3N2) pandemic and oseltamivir during the 2009–2010 influenza A(H1N1)pdm09 pandemic. Antiviral treatment reduces symptom severity, prevents complications, and can reduce onward transmission of infection. However, resistance, accessibility, and timing pose challenges. Future research directions include innovative therapies and combination treatments. Continued research and stewardship are crucial to optimize antiviral impact.

Source: Journal of Infectious Diseases, https://academic.oup.com/jid/article/232/Supplement_3/S215/8287908

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Non-neutralizing #antibodies to #influenza A #matrix-protein-2-ectodomain are broadly effective #therapeutics and resistant to viral escape mutations

 

Abstract

Influenza A viruses remain a global health threat, yet no universal antibody therapy exists. Clinical programs have centered on neutralizing mAbs, only to be thwarted by strain specificity and rapid viral escape. We instead engineered three non-neutralizing IgG2a mAbs that target distinct, overlapping epitopes within the conserved N terminus of the M2 ectodomain (M2e). Combined at low dose, this “triple M2e-mAb” confers robust prophylactic and therapeutic protection in mice challenged with diverse human and zoonotic IAV strains, including highly pathogenic variants. Therapeutic efficacy depends on Fc-mediated effector activity via FcγRI, FcγRIII, and FcγRIV, rather than in vitro neutralization. Serial passaging in triple M2e-mAb–treated immunocompetent and immunodeficient hosts failed to generate viral escape mutants. Our findings redefine the influenza-specific antibody therapeutic design and support Fc-optimized, non-neutralizing M2e-mAbs as a broadly effective, mutation-resistant, off-the-shelve therapy with direct relevance to human pandemic preparedness.

Source: Science Advances, https://www.science.org/doi/10.1126/sciadv.adx3505

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#Azelastine Nasal #Spray for #Prevention of #SARS-CoV-2 Infections A Phase 2 #RCT

 

Key Points

-- Question: Is regular application of azelastine nasal spray associated with reduced risk of SARS-CoV-2 infections?

- Findings: In this randomized placebo-controlled clinical trial that included 450 participants, the incidence of laboratory-confirmed SARS-CoV-2 infections was significantly lower with application of azelastine nasal spray compared with placebo treatment.

-- Meaning: The use of azelastine nasal spray may help to reduce the risk of SARS-CoV-2 infections.

Abstract

Importance  

Limited pharmaceutical options exist for preexposure prophylaxis of COVID-19 beyond vaccination. Azelastine, an antihistamine nasal spray used for decades to treat allergic rhinitis, has in vitro antiviral activity against respiratory viruses, including SARS-CoV-2.

Objective  

To determine the efficacy and safety of azelastine nasal spray for prevention of SARS-CoV-2 infections in healthy adults.

Design, Setting, and Participants  

A phase 2, double-blind, placebo-controlled, single-center trial was conducted from March 2023 to July 2024. Healthy adults from the general population were enrolled at the Saarland University Hospital in Germany.

Interventions  

Participants were randomly assigned 1:1 to receive azelastine, 0.1%, nasal spray or placebo 3 times daily for 56 days. SARS-CoV-2 rapid antigen testing (RAT) was conducted twice weekly, with positive results confirmed by polymerase chain reaction (PCR). Symptomatic participants with negative RAT results underwent multiplex PCR testing for respiratory viruses.

Main Outcome  

The primary end point was the number of PCR-confirmed SARS-CoV-2 infections during the study.

Results  

A total of 450 participants were randomized, with 227 assigned to azelastine and 223 to placebo; 299 (66.4%) were female, 151 (33.6%) male, with a mean (SD) age of 33.0 (13.3) years. Most were White (417 [92.7%]), with 4 (0.9%) African, 22 (4.9%) Asian, and 7 (1.6%) of other ethnicity. In the intention-to-treat (ITT) population, the incidence of PCR-confirmed SARS-CoV-2 infection was significantly lower in the azelastine group (n = 5 [2.2%]) compared with the placebo group (n = 15 [6.7%]) (OR, 0.31; 95% CI, 0.11-0.87). As secondary end points, azelastine demonstrated an increase in mean (SD) time to SARS-CoV-2 infection among infected participants (31.2 [9.3] vs 19.5 [14.8] days), a reduction of the overall number of PCR-confirmed symptomatic infections (21 of 227 participants vs 49 of 223 participants), and a lower incidence of PCR-confirmed rhinovirus infections (1.8% vs 6.3%). Adverse events were comparable between the groups.

Conclusions and Relevance  

In this single-center trial, azelastine nasal spray was associated with reduced risk of SARS-CoV-2 respiratory infections. These findings support the potential of azelastine as a safe prophylactic approach warranting confirmation in larger, multicentric trials.

Trial registration  EudraCT number: 2022-003756-13

Source: JAMA Internal Medicine, https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2838335

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Post-exposure #prophylaxis regimen of #rabies monoclonal #antibody and #vaccine in category 3 potential exposure patients ...

 

Summary

Background

Rabies is almost invariably fatal. A rabies monoclonal antibody (RmAb) was approved in India in 2016 for passive prophylaxis. This post-marketing study aimed to evaluate the long-term safety, immunogenicity, and efficacy of a post-exposure prophylaxis (PEP) regimen containing RmAb.

Methods

This phase 4, open-label, randomised, active-controlled study was conducted at 15 tertiary care hospitals in India. Patients aged 2 years or older with WHO category 3 rabies exposure by a suspected rabid animal were eligible if the exposure occurred less than 72 h before enrolment, or less than 24 h before enrolment for exposures to the face, neck, hand, or fingers. Participants were randomly assigned (3:1) to receive either RmAb (Rabishield; Serum Institute of India, Pune, India) plus a purified Vero cell rabies vaccine (PVRV; Rabivax-S) or equine rabies immunoglobulin (ERIG; Equirab) plus PVRV as PEP. In each treatment group, patients were further randomly assigned (1:1) to receive PVRV either intradermally or intramuscularly. Study group allocation was done using a permuted block design with random block sizes of eight. A central randomisation list was generated before the study start and randomisation was performed with an interactive web response system. Participants and site personnel were not masked to group assignment. RmAb (3·33 IU/kg) and ERIG (40 IU/kg) were infiltrated into and around the wounds only on day 0 as per WHO 2018 recommendations. PVRV was administered 1·0 mL intramuscularly (days 0, 3, 7, 14, and 28) or 0·1 mL plus 0·1 mL intradermally (days 0, 3, 7, and 28). The primary outcome was treatment-related serious adverse events up to 365 days after immunisation, analysed in the safety analysis set (all participants who received at least one dose of vaccine with treatment). Geometric mean concentrations of rabies virus neutralising antibody were measured in a subset of patients. This study is registered with Clinical Trial Registry–India (CTRI/2019/06/019622) and is completed.

Findings

4059 participants were enrolled between Aug 21, 2019, and March 31, 2022, and randomly assigned. A total of 3994 participants (3001 male, 993 female) were treated (2996 RmAb plus PVRV, 998 ERIG plus PVRV), of which 3622 (90·7%) participants completed the 1-year follow-up. 11 adverse events were considered causally related to RmAb plus PVRV and 17 were considered causally related to the ERIG plus PVRV regimen. Most adverse events were mild and transient. Seven serious adverse events occurred in the RmAb group and all were causally unrelated. One causally related serious adverse event was reported in the ERIG group. On day 14, the geometric mean concentrations increased to 16·05 IU/mL (95% CI 13·25–19·44) in the RmAb group and 13·48 IU/mL (9·51–19·11) in the ERIG group (point estimate 1·19 [95% CI 0·82–1·72]). No patient developed rabies during the 1-year follow-up period.

Interpretation

RmAb was safe and well tolerated and showed protective efficacy against rabies. A PEP regimen containing RmAb plus PVRV was immunogenic with long-term persistence of immune response.

Funding

Serum Institute of India.

Source: Lancet, https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(25)00735-4/abstract?rss=yes

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Efficacy of #Baloxavir #Treatment in Preventing #Transmission of #Influenza

Abstract

Background

Baloxavir marboxil (baloxavir) rapidly reduces influenza virus shedding, which suggests that it may reduce transmission. Studies of treatment with neuraminidase inhibitors have not shown sufficient evidence that they prevent transmission to contacts.

Methods

We conducted a multicountry, phase 3b trial to assess the efficacy of single-dose baloxavir treatment to reduce influenza transmission from index patients to household contacts. Influenza-positive index patients 5 to 64 years of age were randomly assigned in a 1:1 ratio to receive baloxavir or placebo within 48 hours after symptom onset. The primary end point was transmission of influenza virus from an index patient to a household contact by day 5. The first secondary end point was transmission of influenza virus by day 5 that resulted in symptoms.

Results

Overall, 1457 index patients and 2681 household contacts were enrolled across the 2019–2024 influenza seasons; 726 index patients were assigned to the baloxavir group, and 731 to the placebo group. By day 5, transmission of laboratory-confirmed influenza was significantly lower with baloxavir than with placebo (adjusted incidence, 9.5% vs. 13.4%; adjusted odds ratio, 0.68; 95.38% confidence interval [CI], 0.50 to 0.93; P=0.01), with an adjusted relative risk reduction of 29% (95.38% CI, 12 to 45). The adjusted incidence of transmission of influenza virus by day 5 that resulted in symptoms was 5.8% with baloxavir and 7.6% with placebo; however, the difference was not significant (adjusted odds ratio, 0.75; 95.38% CI, 0.50 to 1.12; P=0.16). Emergence of drug-resistant viruses during the follow-up period occurred in 7.2% (95% CI, 4.1 to 11.6) of the index patients in the baloxavir group; no resistant viruses were detected in household contacts. No new safety signals were identified.

Conclusions

Treatment with a single oral dose of baloxavir led to a lower incidence of transmission of influenza virus to close contacts than placebo. (Funded by F. Hoffmann–La Roche and others; CENTERSTONE ClinicalTrials.gov number, NCT03969212.)

Source: The New England Journal of Medicine, https://www.nejm.org/doi/full/10.1056/NEJMoa2413156?query=TOC

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#Antiviral use and the effects of #drug #resistance on the #transmission dynamics of #influenza

Abstract

The effectiveness of antivirals in mitigating influenza outbreaks depends on both their ability to reduce the number of infections and the risk of drug resistance. We extended a previously developed mathematical model to investigate the impact of mitigation strategies, including mono or combination antiviral treatment or chemoprophylaxis and vaccination, on influenza transmission dynamics. Our findings indicate that chemoprophylaxis is more effective than treatment in reducing influenza burden, except when the resistant strain has a high transmission rate, in which case chemoprophylaxis may trigger a resistance-driven secondary infection wave. Combination therapy considerably reduces resistance emergence with similar infection numbers as mono-therapy. Vaccination coverage of at least 80% is required to prevent outbreaks; otherwise, antivirals can contribute to outbreak control provided drug resistance emergence is low. This analysis could inform public health decision-making by providing guidance on effective mitigation strategies for influenza outbreaks, considering their benefits against the risk of drug resistance.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.03.10.25323668v1

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Evaluation of #influenza #antiviral #prophylaxis for long-term care residents: a systematic review and meta-analysis

Abstract

Background

Influenza is a pervasive respiratory infection which disproportionately burdens long-term care residents. To limit outbreaks, guidelines recommend antiviral prophylaxis, particularly oseltamivir or zanamivir, despite acknowledging the inadequate supporting evidence. Therefore, we aimed to review the literature on the efficacy of oseltamivir, zanamivir, and baloxavir prophylaxis for influenza in long-term care.

Methods

Medline, Embase, PubMed, and several other databases were searched from inception to August 16, 2023. For inclusion, observational studies or randomized controlled trials (RCTs) had to report influenza-like illness (ILI) or infection rates amongst adult long-term care populations receiving prophylaxis. Outcome values were meta-analyzed as intervention-specific pooled proportions (PPs) and risk ratios (RRs) when applicable. Risk of bias was assessed via the Cochrane risk of bias tool 2.0 and Joanna Briggs Institute checklist.

Results

In total, 14 studies were included, comprising 12,672 residents. Individuals given oseltamivir or zanamivir experienced the fewest symptomatic, test-confirmed infections (oseltamivir PP: 0.7%, 95%CI: 0.1-4.7%, zanamivir PP: 3.0%, 95%CI: 0.9-9.4%) and ILIs (oseltamivir PP: 2.8%, 95%CI: 1.8-4.3%, zanamivir PP: 3.4%, 95%CI: 1.3-7.2%). However, no significant statistical differences were detected versus most other interventions (ILI PP range: 4.5-6.4%, infection PP range: 4.6-7.9%). Similarly, in studies directly comparing either antiviral to placebo, there were no associated benefits despite every RR being below 1 (0.51-0.75) due to expansive 95%CIs.

Conclusions

Oseltamivir or zanamivir could provide some benefit but low statistical power behind most estimates precluded definitive conclusions. Therefore, additional studies (RCTs) are needed to expand the evidence base and validate whether prophylaxis is beneficial in this setting.

Source: Clinical Infectious Diseases, https://academic.oup.com/cid/advance-article-abstract/doi/10.1093/cid/ciaf101/8064583?redirectedFrom=fulltext

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