Adherence with oseltamivir chemoprophylaxis among workers exposed to poultry during avian influenza outbreaks in southern Israel

Assessment of Adherence to Post-exposure Prophylaxis with Oseltamivir in Healthcare Workers: A Retrospective Questionnaire-Based Study

Post-exposure prophylaxis (PEP) for healthcare workers is one of the effective strategies for preventing nosocomial outbreaks of influenza. However, PEP adherence in healthcare workers is rarely analysed, and no strategies have been established to improve adherence to PEP for healthcare workers. We aimed to retrospectively analyse adherence to PEP and the factors associated with non-adherence in healthcare workers. A survey of 221 healthcare workers who were eligible for PEP at Tokushima University Hospital in the 2016/2017 season was conducted. Once-daily oseltamivir (75 mg for 10 d) was used as the PEP regimen. Of the 221 healthcare workers, 175 received PEP and were surveyed for adherence using a questionnaire. Of the 130 healthcare workers who responded to the questionnaire, 121 (93.1%) had been vaccinated. In this survey, 82 healthcare workers (63.1%) did not fully complete PEP. Multiple logistic regression analysis revealed that physicians (odds ratio: 4.62, 95% confidence interval [CI]: 2.08-10.25) and non-vaccination (odds ratio: 9.60, 95% CI: 1.12-82.25) were the factors for non-adherence to PEP. Of the 47 healthcare workers who responded to the item regarding reasons for non-adherence, 36 (76.6%) reported forgetting to take oseltamivir or discontinuing it due to a misguided self-decision that continuation of PEP was unnecessary, and 5 (10.6%) reported discontinuing treatment due to adverse effects. In conclusion, healthcare workers, particularly physicians, had low PEP adherence owing to forgetting or stopping to take oseltamivir due to a misguided self-decision. To obtain the maximum preventive effect of PEP, medication education should be provided to endorse PEP compliance.

Non-Adherence Tree Analysis (NATA)-An adherence improvement framework: A COVID-19 case study

Poor medication adherence is a global phenomenon that has received a significant amount of research attention yet remains largely unsolved. Medication non-adherence can blur drug efficacy results in clinical trials, lead to substantial financial losses, increase the risk of relapse and hospitalisation, or lead to death. The most common methods of measuring adherence are post-treatment measures; that is, adherence is usually measured after the treatment has begun. What the authors are proposing in this multidisciplinary study is a new technique for predicting the factors that are likely to cause non-adherence before or during medication treatment, illustrated in the context of potential non-adherence to COVID-19 antiviral medication. Fault Tree Analysis (FTA), allows system analysts to determine how combinations of simple faults of a system can propagate to cause a total system failure. Monte Carlo simulation is a mathematical algorithm that depends heavily on repeated random sampling to predict the behaviour of a system. In this study, the authors propose a new technique called Non-Adherence Tree Analysis (NATA), based on the FTA and Monte Carlo simulation techniques, to improve adherence. Firstly, the non-adherence factors of a medication treatment lifecycle are translated into what is referred to as a Non-Adherence Tree (NAT). Secondly, the NAT is coded into a format that is translated into the GoldSim software for performing dynamic system modelling and analysis using Monte Carlo. Finally, the GoldSim model is simulated and analysed to predict the behaviour of the NAT. NATA is dynamic and able to learn from emerging datasets to improve the accuracy of future predictions. It produces a framework for improving adherence by analysing social and non-social adherence barriers. Novel terminologies and mathematical expressions have been developed and applied to real-world scenarios. The results of the application of NATA using data from six previous studies in relation to antiviral medication demonstrate a predictive model which suggests that the biggest factor that could contribute to non-adherence to a COVID-19 antiviral treatment is a therapy-related factor (the side effects of the medication). This is closely followed by a condition-related factor (asymptomatic nature of the disease) then patient-related factors (forgetfulness and other causes). From the results, it appears that side effects, asymptomatic factors and forgetfulness contribute 32.44%, 22.67% and 18.22% respectively to discontinuation of medication treatment of COVID-19 antiviral medication treatment. With this information, clinicians can implement relevant interventions and measures and allocate resources appropriately to minimise non-adherence.

A systematic review of factors affecting intended and actual adherence with antiviral medication as treatment or prophylaxis in seasonal and pandemic flu

The aim of this review was to identify factors predicting actual or intended adherence to antivirals as treatment or prophylaxis for influenza. Literature from inception to March 2015 was systematically reviewed to find studies reporting predictors of adherence to antivirals and self‐reported reasons for non‐adherence to antivirals. Twenty‐six studies were included in the review; twenty identified through the literature search and six through other means. Of these studies, 18 assessed predictors of actual adherence to antivirals, whereas eight assessed predictors of intended adherence. The most commonly found predictor of, and self‐reported reason for, non‐adherence was the occurrence of side effects. Other predictors include perceptions surrounding self‐efficacy, response efficacy and perceived personal consequences as well as social influences of others' experiences of taking antivirals. Predictors identified in this review can be used to help inform communications to increase adherence to antivirals in both seasonal and pandemic influenza.

Assessment of serosurveys for H5N1

BACKGROUND

It has been suggested that the true case-fatality rate of human H5N1 influenza infection is appreciably less than the figure of approximately 60% that is based on official World Health Organization (WHO)-confirmed case reports because asymptomatic cases may have been missed. A number of seroepidemiologic studies have been conducted in an attempt to identify such missed cases.

METHODS

We conducted a comprehensive literature review of all English-language H5N1 human serology surveys with detailed attention to laboratory methodology used (including whether investigators used criteria set by the WHO to define positive cases), laboratory controls used, and the clades/genotypes involved.

RESULTS

Twenty-nine studies were included in the analysis. Few reported using unexposed control groups and one-third did not apply WHO criteria. Of studies that used WHO criteria, only 4 found any seropositive results to clades/genotypes of H5N1 that are currently circulating. No studies reported seropositive results to the clade 2/genotype Z viruses that have spread throughout Eurasia and Africa.

CONCLUSIONS

This review suggests that the frequency of positive H5 serology results is likely to be low; therefore, it is essential that future studies adhere to WHO criteria and include unexposed controls in their laboratory assays to limit the likelihood of false-positive results.

Seroevidence for H5N1 influenza infections in humans: meta-analysis

The prevalence of avian H5N1 influenza A infections in humans has not been definitively determined. Cases of H5N1 infection in humans confirmed by the World Health Organization (WHO) are fewer than 600 in number, with an overall case fatality rate of >50%. We hypothesize that the stringent criteria for confirmation of a human case of H5N1 by WHO do not account for a majority of infections but rather the select few hospitalized cases that are more likely to be severe and result in poor clinical outcome. Meta-analysis shows that 1 to 2% of more than 12,500 study participants from 20 studies had seroevidence for prior H5N1 infection.

Mammalian-transmissible H5N1 influenza: facts and perspective

Two recently submitted (but as yet unpublished) studies describe success in creating mutant isolates of H5N1 influenza A virus that can be transmitted via the respiratory route between ferrets; concern has been raised regarding human-to-human transmissibility of these or similar laboratory-generated influenza viruses. Furthermore, the potential release of methods used in these studies has engendered a great deal of controversy around publishing potential dual-use data and also has served as a catalyst for debates around the true case-fatality rate of H5N1 influenza and the capability of influenza vaccines and antivirals to impact any future unintentional or intentional release of H5N1 virus. In this report, we review available seroepidemiology data for H5N1 infection and discuss how case-finding strategies may influence the overall case-fatality rate reported by the WHO. We also provide information supporting the position that if an H5N1 influenza pandemic occurred, available medical countermeasures would have limited impact on the associated morbidity and mortality.

Respiratory illnesses in Canadian health care workers: a pilot study of influenza vaccine and oseltamivir prophylaxis during the 2007/2008 influenza season

BACKGROUND

Data regarding both rates of acute respiratory illness in health care workers and experience with long-term antiviral prophylaxis are sparse.

OBJECTIVE

To determine the efficacy and tolerability of oseltamivir prophylaxis versus seasonal influenza vaccine for the prevention of influenza among health care workers.

METHODS

We conducted a pilot, randomized control study during the 2007/2008 influenza season in a tertiary care setting. Adult health care workers 18-69 years of age were recruited and randomly assigned in a 4:1 ratio to receive either oseltamivir (Tamiflu(®); Roche) 75 mg once daily prophylaxis or seasonal influenza (Fluviral(®)) vaccine.

RESULTS

Of 56 adults enrolled, 12 received vaccine and 44 received prophylaxis. Incidence of symptomatic laboratory-confirmed influenza was similar for participants in the vaccine and prophylaxis arms (17% and 24%, respectively; P = 0·71). Participants who developed an acute respiratory illness during the study period reported working 85% of scheduled work days, and 29% stated that they worked despite feeling miserable because they were too busy to stay home. Of 42 participants who initiated oseltamivir prophylaxis, four discontinued it owing to side effects. Median duration of oseltamivir prophylaxis was 121 days, with 34 (81%) continuing ≥12 weeks.

CONCLUSIONS

During an extended season of suboptimal vaccine match, 22% of health care workers receiving antiviral prophylaxis or seasonal influenza vaccine developed symptomatic laboratory-confirmed influenza. Long-term antiviral prophylaxis against influenza was generally well tolerated with good compliance.