Influenza Division, US Centers for Disease Control and Prevention; Atlanta, GA, USA.
Battelle; Atlanta, GA, USA.
Clin Infect Dis. 2017 Mar 1;64(5):544-550. doi: 10.1093/cid/ciw816. Epub 2016 Dec 29.
Recent studies suggest that influenza vaccine effectiveness (VE) may wane over the course of an influenza season, leading to suboptimal VE during late influenza seasons.
We examined the association between influenza VE and time since vaccination among patients ≥9 years old with medically-attended acute respiratory illness in the US Influenza Vaccine Effectiveness Network using data pooled from the 2011-12 through 2014-15 influenza seasons. We used multivariate logistic regression with PCR-confirmed influenza infection as the outcome and vaccination status defined by days between vaccination and symptom onset as the predictor. Models were adjusted for calendar time and other potential confounding factors.
We observed decreasing VE with increasing time since vaccination for influenza A(H3N2) (p=0.004), influenza A(H1N1)pdm09 (p=0.01), and influenza B viruses (p=0.04). Maximum VE was observed shortly after vaccination, followed by a decline in VE of about 7% (absolute) per month for influenza A(H3N2) and influenza B and 6% - 11% per month for influenza A(H1N1)pdm09 viruses. VE remained greater than zero for at least six months for influenza A(H1N1)pdm09 and influenza B and at least five months for influenza A(H3N2) viruses. Decline in VE was more pronounced among patients with prior season influenza vaccination. A similar pattern of increasing influenza risk with increasing time since vaccination was seen in analyses limited to vaccinees.
We observed decreasing influenza vaccine protection with increasing time since vaccination across influenza types/subtypes. This association is consistent with intraseason waning of host immunity, but bias or residual confounding could explain these findings.
最近的研究表明，流感疫苗的有效性（VE）可能会在流感季节期间逐渐减弱，导致流感后期的 VE 不理想。
我们使用美国流感疫苗有效性网络在 2011-12 至 2014-15 流感季节期间汇总的数据，检查了≥9 岁因急性呼吸道疾病就诊的患者中流感 VE 与接种后时间之间的关联。我们使用多变量逻辑回归，将聚合酶链反应（PCR）确诊的流感感染作为结果，将接种状态定义为疫苗接种与症状出现之间的天数作为预测因素。模型调整了日历时间和其他潜在的混杂因素。
我们观察到，随着接种后时间的增加，流感 A（H3N2）（p=0.004）、流感 A（H1N1）pdm09（p=0.01）和流感 B 病毒的 VE 逐渐降低。在接种后不久观察到最大 VE，随后流感 A（H3N2）和 B 病毒的 VE 每月下降约 7%（绝对值），流感 A（H1N1）pdm09 病毒的 VE 每月下降 6%-11%。对于流感 A（H1N1）pdm09 和 B 病毒，VE 至少在六个月以上保持大于零，对于流感 A（H3N2）病毒，VE 至少在五个月以上保持大于零。在有既往季节流感疫苗接种史的患者中，VE 的下降更为明显。在仅针对疫苗接种者的分析中，也观察到随着接种后时间的增加，流感风险逐渐增加的类似模式。
我们观察到，随着接种后时间的增加，流感疫苗的保护作用逐渐减弱，跨越流感类型/亚型。这种关联与宿主免疫的季节性减弱一致，但可能存在偏差或残留混杂因素导致这些发现。
