GH515, School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, Hong Kong, Special Administrative Region of China.
School of Public Health, The University of Hong Kong, Hong Kong, Hong Kong, Special Administrative Region of China.
BMC Infect Dis. 2019 Feb 14;19(1):162. doi: 10.1186/s12879-019-3735-7.
Influenza and pneumococcal vaccine uptake in the older population aged 65 years or over of Hong Kong dramatically increased since the 2003 SARS outbreak. This study is aimed to evaluate the impact of increased coverage of influenza and pneumococcal vaccines by comparing the change of disease burden in the older population of Hong Kong, with the burden in the older population of Brisbane with relatively high vaccine coverage in the past fifteen years.
Time series segmented regression models were applied to weekly numbers of cause-specific mortality or hospitalization of Hong Kong and Brisbane. Annual excess rates of mortality or hospitalization associated with influenza in the older population were estimated for the pre-SARS (reference period), post-SARS and post-pandemic period, respectively. The rate ratios (RRs) between these periods were also calculated to assess the relative change of disease burden.
Compared to the pre-SARS period, excess rates of mortality associated with influenza during the post-SARS period in Hong Kong decreased for cardiorespiratory diseases (RR = 0.90, 95% CI 0.80, 1.01), stroke (RR = 0.74, 95% CI 0.50, 1.09), and ischemic heart diseases (RR = 0.45, 95% CI 0.34, 0.58). The corresponding RRs in Brisbane were 0.79 (95% CI 0.54, 1.15), 0.33 (0.13, 0.80), and 1.09 (0.62, 1.90), respectively. Only the mortality of ischemic heart diseases showed a greater reduction in Hong Kong than in Brisbane. During the post-pandemic period, excess rates of all-cause mortality increased in Hong Kong, but to a lesser extent than in Brisbane (RR = 1.41 vs 2.39).
A relative decrease (or less of an increase) of influenza disease burden was observed in the older population of Hong Kong after increased coverage of influenza and pneumococcal vaccines in this population, as compared to those of Brisbane where vaccination rates remained stable. The lack of significant findings in some disease categories highlights the challenges of evaluating the benefits of vaccination at the population level.
自 2003 年 SARS 爆发以来，香港 65 岁及以上老年人的流感和肺炎球菌疫苗接种率大幅上升。本研究旨在通过比较香港老年人群疾病负担的变化与过去 15 年疫苗覆盖率相对较高的布里斯班老年人群的疾病负担，评估流感和肺炎球菌疫苗覆盖率增加的影响。
采用时间序列分段回归模型分析香港和布里斯班每周特定病因死亡率或住院率。分别估计 SARS 前（参考期）、SARS 后和大流行后时期流感相关老年人群的超额死亡率或住院率。还计算了这些时期之间的比率比（RR），以评估疾病负担的相对变化。
与 SARS 前时期相比，香港 SARS 后时期流感相关的心血管疾病（RR=0.90，95%CI 0.80，1.01）、中风（RR=0.74，95%CI 0.50，1.09）和缺血性心脏病（RR=0.45，95%CI 0.34，0.58）死亡率的超额率降低。布里斯班的相应 RR 分别为 0.79（95%CI 0.54，1.15）、0.33（0.13，0.80）和 1.09（0.62，1.90）。只有缺血性心脏病的死亡率在香港的下降幅度大于布里斯班。大流行后时期，香港全因死亡率的超额率增加，但增幅小于布里斯班（RR=1.41 比 2.39）。
与布里斯班相比，香港老年人群流感和肺炎球菌疫苗覆盖率增加后，老年人群的流感疾病负担相对减少（或增加幅度较小），而布里斯班的疫苗接种率保持稳定。在某些疾病类别中未发现显著结果，突出了在人群水平评估疫苗接种效益所面临的挑战。
