We always wash our lettuce. But that means rinsing it in cold water and draining it, not washing it with warm water and soap.
I'm not insure that washing infected lettuce would be enough. And although so far this outbreak appears to be restricted to California, California lettuce is shipped all over the country.
I think they'd better trace down the source.
Realistically, even a good cold water wash will so greatly reduce the bacterial count by cavitation (e.g. mechanicl removal from the substrate) that only people with badly compromised immune systems would ever stand a change of getting infected. It's all about probability.
The article says it might be helpful to use a brush when you wash the lettuce. Good grief, I'm not about to start washing lettuce leaf-by-leaf because a handful of people got sick. We would all be Bubble-Boys if we succumbed to each and every one of these health scares!