First of all, let's just clarify that the virus mutates in its natural state, and we've seen the emergence of variants without any pressure from the vaccine. As for what vaccines do, if you can reduce the number of cases, together with public health measures, then fewer cases mean less ability for the virus to mutate.
Now, of course we have a number of mechanisms and studies that are foundational to the rollout of the vaccines. Measuring vaccine effectiveness is really key, and you've seen some of the data beginning to come out of B.C. and Quebec. Those mechanisms are already in existence. We'll keep monitoring the interval and vaccine effectiveness over time as the interval increases, so that is already there.
The other thing we've done is increase the infrastructure for the sequencing and screening of variants of concern. One of the key protocols is that for anyone who has been vaccinated—and it doesn't matter if it's one dose or two doses—samples need to be sequenced so that we can detect if there are any variants emerging. That capacity has increased really fast, with much higher sequencing now than we had even a couple of months ago. Over 10,000—and maybe 11,000—sequences were performed last month. We'll be watching that really carefully and we'll be able to provide that information.