This article is from the Childhood Vaccinations FAQ, by Lynn Gazis-Sax email@example.com with numerous contributions by others.
Again, VAERS accepts all reports of adverse events following
vaccination, so not all events reported to VAERS are caused by
vaccines. In fact, limitations such as differential reporting rates,
simultaneous administration of different vaccine antigens, temporal
reporting bias and lack of background vaccination rate data generally
prevent the determination of vaccine-event causal associations using