What's curious for me is that WFF is publishing this on their blog now.....the article appeared one year ago. Interesting.
It's also important to keep in mind that this is a Canadian study based on Canadian data. Histovet (http://www.histovet.com) had previously put on its site two reports on VAS in Canada (2004, 2007). The earlier is no longer available there, the latter is here: http://www.histovet.com/PDFs/HIS_PostVaccinal.pdf.