To the Editor—In their recent publication, Luca et al [1] used an ecological design to compare all-cause pneumonia hospitalizations and associated costs in Ontario before (1992–2001) and after infant pneumococcal conjugate vaccine (PCV) availability—initially as 7-valent PCV (PCV7) for private purchase (2001–2004), then as publicly funded programs of PCV7 (2005–2009), 10-valent PCV (2009–2010), and 13-valent PCV (2010–2014). The authors attribute large reductions in pneumonia hospitalizations to the direct and indirect effects of infant PCV—reaching a 45% reduction among infants and a comparable reduction of 40% in elderly adults.

中文翻译：

---

生态谬误，非特异性结果和不成比例的疫苗惠益归因

致编辑-Luca等人[1]在最近的出版物中使用了一种生态学设计，比较了1992年至2001年之前和之后婴儿肺炎球菌结合疫苗（PCV）可获得性期间安大略省的全因肺炎住院和相关费用。 7价PCV（PCV7）供私人购买（2001-2004），然后作为PCV7（2005-2009），10价PCV（2009-2010）和13价PCV（2010-2014）的公共资助计划。作者将肺炎住院的大幅减少归因于婴儿PCV的直接和间接作用-婴儿中PCV减少了45％，而老年人则减少了40％。