According to the SDCC Unofficial Blog, an email was sent out to volunteers asking them "to volunteer at a non-profit organization their area between now and July 26" while also using the hashtag #SDCCVOLUNTEERCHALLENGE online. As of this writing there was only one instance of the hashtag having being used on Twitter and one instance on Instagram. Luckily there's still plenty of time between now and July 26.
Though the convention itself isn't happening, an online component is set to take place in some capacity. Further details on the event have not yet been announced, but the organization previously said their hope is for the digital event to "convey some of the excitement of Comic-Con."
“Extraordinary times require extraordinary measures and while we are saddened to take this action, we know it is the right decision,” said David Glanzer, spokesperson for the organization said when the cancellation was confirmed. “We eagerly look forward to the time when we can all meet again and share in the community we all love and enjoy.”