They found that most of the citations were in the context of how the paper has influenced public perception of vaccines and increased anti-vax sentiment and it was referenced in a negative way.
One finding of concern was that a substantial proportion did not report the fact the paper has been retracted. They note that,
The authors raise the problem of citation managers not flagging that papers that have been retracted, and how the current system puts the onus on academics to be pro-active and be aware of retractions. They discuss work they have done with Zotero to automatically update citations with retraction notices which sounds like a fantastic idea, and one that hopefully other reference managers can also develop, and extend to cover errata as well.The retraction of the Wakefield study is very well known and if authors are failing to note the retracted status of this article, we are concerned that lesser known retracted articles are being cited without documenting their retraction