Department of Industrial Engineering, Tel Aviv University, 55 Haim Levanon St, Tel Aviv, Israel.
Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843, USA.
BMC Med. 2021 Mar 1;19(1):54. doi: 10.1186/s12916-021-01926-5.
Seasonal influenza remains a major cause of morbidity and mortality in the USA. Despite the US Centers for Disease Control and Prevention recommendation promoting the early antiviral treatment of high-risk patients, treatment coverage remains low.
To evaluate the population-level impact of increasing antiviral treatment timeliness and coverage among high-risk patients in the USA, we developed an influenza transmission model that incorporates data on infectious viral load, social contact, and healthcare-seeking behavior. We modeled the reduction in transmissibility in treated individuals based on their reduced daily viral load. The reduction in hospitalizations following treatment was based on estimates from clinical trials. We calibrated the model to weekly influenza data from Texas, California, Connecticut, and Virginia between 2014 and 2019. We considered in the baseline scenario that 2.7-4.8% are treated within 48 h of symptom onset while an additional 7.3-12.8% are treated after 48 h of symptom onset. We evaluated the impact of improving the timeliness and uptake of antiviral treatment on influenza cases and hospitalizations.
Model projections suggest that treating high-risk individuals as early as 48 h after symptom onset while maintaining the current treatment coverage level would avert 2.9-4.5% of all symptomatic cases and 5.5-7.1% of all hospitalizations. Geographic variability in the effectiveness of earlier treatment arises primarily from variabilities in vaccination coverage and population demographics. Regardless of these variabilities, we found that when 20% of the high-risk individuals were treated within 48 h, the reduction in hospitalizations doubled. We found that treatment of the elderly population (> 65 years old) had the highest impact on reducing hospitalizations, whereas treating high-risk individuals aged 5-19 years old had the highest impact on reducing transmission. Furthermore, the population-level benefit per treated individual is enhanced under conditions of high vaccination coverage and a low attack rate during an influenza season.
Increased timeliness and coverage of antiviral treatment among high-risk patients have the potential to substantially reduce the burden of seasonal influenza in the USA, regardless of influenza vaccination coverage and the severity of the influenza season.
季节性流感仍然是美国发病率和死亡率的主要原因。尽管美国疾病控制与预防中心建议对高危患者进行早期抗病毒治疗，但治疗覆盖率仍然很低。
为了评估提高美国高危患者抗病毒治疗及时性和覆盖率对人群的影响，我们开发了一个流感传播模型，该模型结合了传染性病毒载量、社会接触和寻求医疗服务行为的数据。我们根据治疗个体每日病毒载量减少的情况，对治疗个体传染性降低的情况进行建模。治疗后住院人数的减少基于临床试验的估计。我们使用 2014 年至 2019 年期间来自德克萨斯州、加利福尼亚州、康涅狄格州和弗吉尼亚州的每周流感数据对模型进行校准。在基线情况下，我们假设 2.7%-4.8%的患者在症状出现后 48 小时内接受治疗，而另外 7.3%-12.8%的患者在症状出现后 48 小时后接受治疗。我们评估了提高抗病毒治疗及时性和覆盖率对流感病例和住院人数的影响。
模型预测表明，高危个体在症状出现后 48 小时内尽早接受治疗，同时保持当前的治疗覆盖率，将避免所有有症状病例的 2.9%-4.5%和所有住院病例的 5.5%-7.1%。早期治疗效果的地理差异主要源于疫苗接种覆盖率和人口统计学特征的差异。无论这些差异如何，我们发现，当 20%的高危个体在 48 小时内接受治疗时，住院人数减少了一倍。我们发现，治疗老年人群（>65 岁）对减少住院人数的影响最大，而治疗 5-19 岁的高危人群对减少传播的影响最大。此外，在流感季节疫苗接种覆盖率高和发病率低的情况下，每治疗一个人带来的人群效益会增强。
提高高危患者抗病毒治疗的及时性和覆盖率有可能显著减轻美国季节性流感的负担，而与流感疫苗接种覆盖率和流感季节的严重程度无关。
