COVID-19 has dropped off the news, but it still poses a significant risk to long-term health, even among people who have caught it before.

Prevalence in the UK is currently low, around 1 in 50 in London on 16 August 2022. However, at this rate, if we took no precautions we’d expect at least 1 person at a typical meeting to be testing positive.

We therefore propose the following precautions. As usual for DC4420, we have limited ability to enforce them, so this is an honesty system. Please read the following section carefully before attending, and decide if it fits your risk appetite.

If we believe someone is making people feel unsafe, we’ll ask them to leave.


Differences from conference policy

For the conference in Las Vegas, Defcon will mandate masks and has previously removed in-person speaking tracks. This makes sense for an international event with thousands of attendees.

Unfortunately, Defcon doesn’t provide COVID-19 guidance for DC groups, so we have chosen to limit ourselves to national guidance for the following reasons:

Outdoors events

As a stop-gap, we’ve run some in-person events outdoors at Battersea Park. If you’re not tied to the talks part of DC4420, please join us! These are announced in advance, and details are posted on Twitter on the day.

Virtual Defcon

During the conference, Defcon plans to provide virtual spaces for socialising and remote streaming of talks. Some UK groups (e.g. Worcester) have also been successful doing this.

A large part of DC4420 is the openness that comes from knowing your words aren’t recorded. However, if you’d like to chat about organising an online event, please get in touch.


If you have any concerns or comments, please email