医学英译

这篇文章是The New England Journal of Medicine的一篇编者按,作者John D. Treanor, M.D. （Volume 357:1439-1441 October 4, 2007 Number 14）

冬天来了,流感疫苗接种又成为一个热门的话题。作者提出既然疫苗可以降低流感的发病危险，那么流感接种者中流感相关的合并症也自然会降低。Since the vaccine reduces the risk of influenza, it would be reasonable to expect that vaccination would also reduce the risks of influenza-related complications in recipients.

可是，也有相反的情况出现，在一段时间内，冬天里的流感住院率和死亡率在上升。Instead, the opposite has occurred, with winter hospitalizations and deaths increasing during this period. （出处：Simonsen L, Reichert TA, Viboud C, Blackwelder WC, Taylor RJ, Miller MA. Impact of influenza vaccination on seasonal mortality in the US elderly population. Arch Intern Med 2005;165:265-272.）

解释有多种，但是以往的队列研究都有时间与研究地点的限制。Many of the previous cohort studies have been limited in that they analyzed only one or two seasons or were conducted at a single site, since reported morbidity due to influenza may vary significantly by season and region.

作者评论的那篇文章（Nichol KL, Nordin JD, Nelson DB, Mullooly JP, Hak E. Effectiveness of influenza vaccine in the community-dwelling elderly. N Engl J Med 2007;357:1373-1381.）处理这些问题，增加我们在老年人群中接种流感疫苗的信心。The study reported by Nichol et al. in this issue of the Journal addresses many of these concerns and increases our confidence in the benefits of influenza vaccination for older adults.

Nichol 等采用保守的统计学方法，最后确定：即使有未确定的混淆因素，流感疫苗依然可相对的降低7%的住院率以及33%的病死率。Nichol et al. have also determined that if an undetected confounder were present, it would have to be very prevalent and have a large effect to account for the effectiveness demonstrated in the study. Using a sensitivity analysis, they showed that even if a factor present in 60% of the population had the effect of decreasing the rate of vaccination by 50%, while also increasing the risk of influenza outcomes by a factor of 3, vaccination would still have a relative effectiveness of at least 7% for hospitalization and 33% for death.

作者提出了流感疫苗要改进。Influenza vaccine is less immunogenic, and probably less effective, in older persons than in young healthy adults, and the development of safe but more immunogenic and effective vaccines for the elderly is an important goal.

此外，要扩大接种人群，这不仅可呵护接种者的健康，也控制了可能的传染源，为老年人群的疫苗接种效果提供了更可靠的保障。

The most intriguing possibility is that high vaccination rates among the general population, particularly among children, might interrupt transmission and provide secondary protection to those who cannot be protected directly by vaccination.