In reply to Flinticus:
You could wear a surgical type mask over or under a valved Ffp* mask, or modify the valve housing to hold something over the valve that will filer the exhaled air (such as a square of material cut from a surgical mask).
Hopefully though, the fact that more people are moving to proper, filtering masks (at long last!) - whether valved or not - will mean fewer people get infected. And if they're not infected, they can't pass it on to others.
Edit:
Here's what the CDC say about valved masks. They provide more protection to others (not the wearer) than you may think:
"My N95 filtering facepiece respirator has an exhalation valve. Is that okay? Will it protect both me and others?"
"Yes, an N95 filtering facepiece respirator will protect you and provide source control to protect others. A NIOSH-approved N95 filtering facepiece respirator with an exhalation valve offers the same protection to the wearer as one that does not have a valve. As source control, findings from NIOSH research suggest that, even without covering the valve, N95 respirators with exhalation valves provide the same or better source control than surgical masks, procedure masks, cloth masks, or fabric coverings. In general, individuals wearing NIOSH-approved N95s with an exhalation valve should not be asked to use one without an exhalation valve or to cover it with a face covering or mask. However, NIOSH-approved N95 respirators with an exhalation valve are not fluid resistant. Therefore, in situations where a fluid resistant respirator is indicated (e.g., in surgical settings), individuals should wear a surgical N95 or, if a surgical N95 is not available, cover their respirator with a surgical mask or a face shield. Be careful not to compromise the fit of the respirator when placing a facemask over the respirator."
Source: https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html
Post edited at 23:14