"Mask-wearing is critical," said Robert Wachter, chair of the Department of Medicine at UCSF. "Large crowds with people shouting is a formula for spread if people aren't wearing masks."
Many protest organizers are also asking that people maintain social distance, 6 feet apart, during marches.
Protests outside are safer, said Art Reingold, professor and head of the division of epidemiology at the UC Berkeley School of Public Health. However, he said he was concerned about the ability of people to maintain social distance.
"The good news is that these marches tend to occur outside and we think the risk of transmission outside is less," Reingold said. "The bad news is that you may be in close proximity to large numbers of people, its probably not very realistic to stay 6 feet away."
Reingold also said that protesters should frequently use hand sanitizer.
COVID-19 and Tear Gas
It's unclear how tear gas and COVID-19 mix, Reingold said. For instance, coughing and crying from tear gas could spread the virus more. But we don't know whether tear gas could kill the virus or impact how long the virus stays on other materials.
Some protesters also bring wet bandanas or masks to help protect themselves from tear gas. However, we do not know whether a wet mask is as effective against the virus, Reingold said.
"In general, we think that when masks become wet that they’re not as good as preventing the spread of virus and we ask people to discard masks when they become wet," he said. "I suppose, in theory, a wet mask might be less effective against the virus, but not necessarily."
Should You Get Tested?
Experts agree that we will probably not know for several weeks about whether people became infected with COVID-19 at the protests. That's because it takes about a week for most people to show symptoms, and not everyone will.
Even once we have them, testing numbers are "squishy," Reingold says.
Hospitalizations, numbers of people admitted the ICU and deaths are more reliable metrics for tracking outbreaks, he said, so it could take four to six weeks to see whether there was an outbreak.
If you want to get tested for COVID-19 after protesting you should wait a week, Reingold said, because we don’t know how long after exposure when the virus is first detectable.
"If you’re really worried and want to get a test because of that exposure I would say that it makes sense to wait a week," he said. "A negative test a few days after being exposed is not very useful."
Experts said that whether protesting is safe depends on the protest.
"If they are and are doing their best to keep a distance from others, it is safe enough that people should make their own choices," said UCSF chair Wachter. "I completely understand the motivation for protesting, and people should just do it as safely as they can."
Have a Plan, and a Backup Plan
There's also a lot you can do before a protest.
Travel With Friends
Choose a meeting place beforehand in the event you get separated. You may also want to designate someone you can check in with who is not at the protest.
Charging your phone is an obvious one. But some activist groups also recommend taking digital security measures, such as disabling the fingerprint unlock feature to prevent a police officer from forcing you to unlock the phone. Others also recommend turning off text preview on messages and using a more secure messaging app such as Signal.
Also, make sure that you can function without a phone. Consider writing down important phone numbers and keeping them with you.
Pack a Small Bag
Only bring essentials such as water, snacks, hand sanitizer and an extra phone charger.
The active component in tear gas adheres to moisture on your face. So it’s also good idea to pack an extra N95 mask or face covering in case you are exposed to tear gas.
Some people recommend bringing basic medical supplies and a bandana soaked in vinegar or water in a sealed plastic bag in case there is tear gas. Others recommend a small bottle of water, or even better, a squirt bottle, to pour on your face and eyes.
Research the Intended Protest Route
This may be confusing since there's not always a clearly stated route (a protest is, or course, not a parade), yet some have pre-planned routes.
By knowing where the protest is headed, you will be able to plan how you might avoid being caught in a kettle or other containment — and leave when you are ready.
Know Who Is Organizing the Protest
San Diego Black Lives Matter organizers have pointed to specific events, recommending people refrain from attending, as they say it may coordinated by a white nationalist group.
Know Your Rights
You are entitled to free speech and freedom of assembly. However, it can be unclear during curfews and shelter-in-place orders. "Know your rights" guides for protests can be found here. Notably, when police issue an order to disperse it is meant to be the last resort for law enforcement.
“If officers issue a dispersal order, they must provide a reasonable opportunity to comply, including sufficient time and a clear, unobstructed exit path,” according to the American Civil Liberties Union.
If you are photographing others, it is recommended to respect privacy, as some may not want to have videos or photos taken. This may also depend on context, location and time of day. In some cases journalists, or those documenting events have been the target of tear gas and rubber bullets.