Department of Social and Preventive Medicine, Laval University, Québec, Québec, Canada.
Clin Ther. 2009 Oct;31(10):2152-69. doi: 10.1016/j.clinthera.2009.10.014.
A heptavalent pneumococcal conjugate vaccine (PCV-7) is available to immunize infants against pneumococcal disease. However, a recently developed vaccine, pneumococcal nontypable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV), has recently been licensed. PHiD-CV contains 3 additional Streptococcus pneumoniae serotypes and may provide protection against nontypable H influenzae (NTHi) infection. New health economic models are required to model the impact of PHiD-CV and compare its effectiveness with PCV-7.
The aim of this article was to design a model capable of projecting the pneumococcal and NTHi disease burden on the entire UK population under different schedules of PCV-7 and PHiD-CV. This model should also be capable of modeling the net indirect effect of vaccination (ie, the sum of serotype replacement and herd protection).
A static, deterministic, age-compartmental model was created based on published information and the input of a board of experts in pneumococcal disease. The model presents results from both a payer-based and societal perspective. A 1-way sensitivity analysis was used to demonstrate the robustness of the model. Key parameters included the case fatality ratio for bacteremia, the hospitalization rate for acute otitis media (AOM), and parameters surrounding the extent of the net indirect effect of vaccination.
Excluding net indirect effect, 325 cases of invasive pneumococcal disease (IPD), 619 hospitalizations for pneumonia, and 9016 general practitioner visits for AOM would be prevented annually with the current PCV-7 2 + 1 program. These numbers would increase to 374, 755, and 30,920, respectively, using a PHiD-CV 2 + 1 regimen, or to 503, 994, and 47,180 using a PHiD-CV 3 + 1 regimen. When a net indirect effect of 38% is considered, health benefits could be much larger; 2417, 2451, and 3045 IPD cases would be prevented in the 3 scenarios, respectively.
It is predicted that any vaccination program in the United Kingdom would have a striking impact on the incidence of all outcomes analyzed. A PHiD-CV 3 + 1 schedule is predicted to have a greater effect than PCV-7 in all scenarios. While the primary purpose of vaccination would be to prevent IPD and pneumonia hospitalizations, an additional benefit would be a noticeable reduction in AOM incidence. While the predictions made by the model were based on informed reasoning, all of its projected estimations remain approximations that are dependent on the inputs used to configure it, a limitation that is common to all simulation models.
目前已有一种 7 价肺炎球菌结合疫苗（PCV-7）可用于预防婴幼儿肺炎球菌疾病。然而，最近开发的肺炎球菌无荚膜流感嗜血杆菌蛋白 D 结合疫苗（PHiD-CV）已获得许可。PHiD-CV 包含 3 种额外的肺炎球菌血清型，可能对无荚膜流感嗜血杆菌（NTHi）感染有保护作用。需要新的健康经济学模型来模拟 PHiD-CV 的影响，并比较其与 PCV-7 的有效性。
本研究旨在设计一种模型，能够预测在不同的 PCV-7 和 PHiD-CV 接种方案下，整个英国人群的肺炎球菌和 NTHi 疾病负担。该模型还应能够对疫苗接种的净间接效应（即血清型替代和群体保护的总和）进行建模。
根据已发表的信息和肺炎球菌疾病专家小组的意见，建立了一个静态、确定性、年龄分组模型。该模型从支付者和社会角度呈现了结果。采用单因素敏感性分析来验证模型的稳健性。关键参数包括菌血症的病死率、急性中耳炎（AOM）的住院率以及疫苗接种净间接效应的范围。
不包括净间接效应，目前的 PCV-7 2+1 方案每年可预防 325 例侵袭性肺炎球菌病（IPD）、619 例肺炎住院和 9016 例普通医生就诊的急性中耳炎（AOM）。如果采用 PHiD-CV 2+1 方案，这些数字将分别增加到 374、755 和 30920，采用 PHiD-CV 3+1 方案则分别增加到 503、994 和 47180。如果考虑 38%的净间接效应，健康获益可能会更大；在这 3 种情况下，分别可预防 2417、2451 和 3045 例 IPD。
预计英国的任何疫苗接种计划都将对所有分析结果的发病率产生显著影响。在所有情况下，PHiD-CV 3+1 方案预计比 PCV-7 更有效。虽然疫苗接种的主要目的是预防 IPD 和肺炎住院，但另一个好处是急性中耳炎发病率的显著降低。模型的预测是基于合理的推理，但所有预测估计仍然是近似值，取决于配置模型所用的输入，这是所有模拟模型的共同限制。
