Swap your cloth mask for a KN95 or N95. Rethink socializing. And more expert omicron advice.

We asked UCSF’s Dr. Kirsten Bibbins-Domingo how people can stay safe in the face of the latest COVID-19 variant.

Tiffany Stanton gets a COVID-19 test in the LifeLong Medical Care parking lot in West Berkeley on January 6, 2022. Credit: Kelly Sullivan
Tiffany Stanton gets a COVID-19 test in the LifeLong Medical Care parking lot in West Berkeley on Jan. 6. Credit: Kelly Sullivan

The new year arrived with an omicron-fueled surge in COVID-19 cases in Berkeley and Alameda County, causing widespread concern and resulting in a number of event cancelations and temporary business closures that recall the pandemic’s early days. 

Given how quickly information about omicron is changing, we decided to reach out to Dr. Kirsten Bibbins-Domingo, a professor at the UCSF School of Medicine, to get some clarity about the current state of affairs.

The interview with Dr. Bibbins Domingo has been edited for length and clarity.

There’s differing information about masking. Does double-masking with a surgical and cloth mask still offer adequate protection? Should we throw away our cloth masks entirely and stick to KN95’s and N95’s? 

Dr. Kirsten Bibbins-Domingo is a professor in the UCSF School of Medicine. Courtesy: UCSF

A cloth mask doesn’t cut it anymore. A surgical mask is better but it doesn’t fit tight enough on our face. The idea of double masking—with the cloth mask over the top of [the surgical mask] to fit tighter on the face — is a solution, but it is not as good as the best solution, which is the KN95 or the N95. If you can get it and it fits within your budget to get it, that is what I would absolutely recommend to everyone. It protects you and it protects everyone else around.

If you are able to get high-quality masks, how long can you wear them? How many uses can one get out of those masks?

If the masks get really wet or dirty, or if you’re sweating into it, I would not be using them more than once. The way we use them and we think about them, even clinically, is that we protect them in paper bags and we can wear them five times. That is generally a good rule of thumb.

There’s been confusion and skepticism around the CDC’s recent change in guidance from 10 days of isolation to five after a positive test. Is it known whether most or all people are no longer infectious after five days? Do you think the shortening of the isolation period was a good idea?

The CDC did change that but California issued its own guidance, which I believe is stronger: Shorten isolation to five days [and] at five days if your symptoms are resolving or you’re symptom-free and take a test, and if you’re negative, you end your isolation. If you are positive you continue in isolation. And if you can’t get a test, you also continue [to isolate] for a total of 10 days. Key things here: Symptoms include fever — you’ve got to be fever-free in order to end isolation — and you should be wearing your high-quality mask throughout when you’re around other people for all 10 days. 

Back to your question: Are people not going to be infectious after five days? The problem is that there’s a whole spectrum. Some people are not going to be infectious after five days, maybe even most people. But that is the reason we want you to test — we want to make sure you’re in that group that’s not infectious. By 10 days, pretty much everyone is not infectious. And so that’s the difference between the CDC and what California recommends. 

The other key here is that the type of test that one should do is a rapid antigen test, not a PCR test because a PCR test can be positive for a long time, even beyond the infectious period. So the good thing about the rapid test is that (if they are positive), they are much more highly correlated with you being infectious, being able to transmit it to others. 

Why are some people testing negative on rapid tests and a day or two later testing positive on a PCR?

We’re in a very dynamic environment right now, and there’s a lot of COVID around. I don’t know, in the specific example you’re giving me, whether people testing actually just had a new infection. Or it could be that they never had enough virus, [so] the rapid test was going to be negative and now the PCR was positive. It’s hard to know. What we know is that once you get infected, if you’ve been exposed to someone, what happens is, it takes a little while for you yourself to get enough virus in your own body to actually make the test be positive. One of the things that people do wrong is that they test too early after being exposed to someone. It could be that in the case you’re describing, those people tested really early, so the virus still takes a little while to build up in you, for you to both have symptoms and for you to have enough virus for you to transmit it to others.

With omicron, how long should someone wait to get tested after being exposed?

Three days is probably when you’re most likely to see [omicron]. With the older variants, it was probably even a little longer, maybe three or four or five days. I would say testing on day three is probably the optimal time for you to see it. I would say if you have had prolonged close contact with someone that you know is positive, though, you should quarantine. Remember, quarantining is not the same as isolating. Isolating is what you do when you are positive. Quarantining is when a family member is positive or someone you live with is positive. You should quarantine and you should follow the rules of quarantine, which are that you behave like you have COVID and you test on day five. 

I’ve been reporting about events being canceled—both indoor and outdoor—and some venues choosing to close down because of the current surge. How safe is it right now to engage in indoor or large outdoor activities? Going to restaurants, kids in school, attending a social gathering, going to a friend’s house. … Are you personally comfortable being in these types of spaces? 

I will say for myself that I am not comfortable being in a place where I’m going to take my mask off with people I don’t know. So that would mean most dining places, including very close settings for dining, and in most places where I am in larger crowds, even if they’re outdoors with people who I don’t know their testing [or] vaccination status. I wouldn’t be comfortable in very large crowds and I wouldn’t be comfortable in places where I have to take my mask off.

“We all have a responsibility to try not to contribute to the virus.”

But, I will also say there’s a lot of virus right now in the Bay Area. I don’t think it’s reasonable to just say, “Well, it doesn’t matter, we should just do whatever we want.” I do think we all should take prudent precautions. I take them. I’m fully boosted. I take them because I live with other people around me who I worry that I don’t want them to even get a mild infection. Yeah, I take those precautions. We all have a responsibility to try not to contribute to the virus, and we also are going to be in a situation where we’re going to see a lot of people test positive.

Are you seeing that omicron is more transmissible outdoors? It seems like there are more breakthrough cases with omicron than there were with delta.

Yes, for sure. What makes omicron special is that it sort of gets around. So, the vaccines work because they protect against severe disease, but the vaccines also protect, to some extent, from people just getting infected. And with the prior variant, I think we relied a lot on that protection from vaccines. And now for people who are boosted, they still offer some protection, but it’s not complete. So if you’re boosted, that’s the ideal situation right now.

“People are really not getting sick in the hospital who are boosted.”

People are really not getting sick in the hospital who are boosted. The virus seems to be able to sneak around our immune system, particularly if you’re unvaccinated. But even if you’re boosted, we will see people who get these breakthrough cases. Sometimes that leads people to think, “Oh, the vaccine and the boosting didn’t work.” The vaccine and boosting worked because it kept you out of the hospital and for some people it might have even prevented them from getting infected in the first place. 

I looked at the rates this morning for San Francisco. The rates are highest [among] the unvaccinated and they are almost as high in those who are vaccinated and not boosted. If I were a person who was not boosted at this point and I knew the boosting was on the horizon, I would go and get boosted now because boosting probably offers you some protection, even within a week. It’s not a 100% guarantee that there’s not going to be a breakthrough but it will give you one more thing that you can do to protect yourself and to protect the communities around you.

With how much virus there is currently, would you say that even meeting with fully vaccinated and boosted people outside of your immediate household is risky to do?

Everything is some risk. If you knew everyone around you was fully vaccinated and boosted I would say that risk is low, but it’s not zero because right now people are positive. I think when you now meet with large numbers of people some of whom are not boosted or vaccinated, you’re substantially increasing your risk, even if you’re masked, and then if you’re in environments where you’re taking your mask off, you’re sort of throwing caution to the wind at this point. I would not be doing that.

My understanding is that we’re better off here in the Bay Area than people in other parts of the country. But at the same time, we see the spiking case rates and the CDC currently has Alameda County listed as a “high risk” area for transmission.

What’s better in the Bay Area is that we have a higher number of people who’ve been vaccinated than in other places. We’ve tried to put the effort out to get the message on boosting, so we have a lot of people who are boosted. That puts us in a better situation, but it is not a perfect situation. And I think one of the challenging messages right now is when people say, “Oh, don’t worry about omicron, it’s mild.” While there’s a lot of virus around, there will be a lot of virus being transmitted. There will be people who are out sick. There will be people whose diabetes gets worse, whose asthma gets worse, they will have challenges with being more sick even with a milder virus. We have to recognize that right now, [more] than we ever have in the Bay Area throughout the pandemic, we have more active virus circulating. We all have to take that seriously because there is more risk in the Bay right now, no doubt. 

What steps should city and school officials be taking given how much virus there is circulating?

“We should not leave it up to people to figure out how to get their own KN95 masks.”

The biggest gap we have right now is, we would love to have more tests. I think the rapid home tests are not as freely available, and by freely available I mean they’re not available and they still cost too much. I would love to see more access to testing. I think if people have tests, then they can make better decisions for themselves and for others. I would like to see high-quality masks being distributed everywhere. We should not leave it up to people to figure out how to get their own KN95 masks. We should be making those widely available. We are in a situation where we want to keep as much of our society functioning as possible, recognizing the risk. The masking and testing can help with that, especially for keeping our kids in school safely. That’s what I would urge to do. 

And as we know, the equity issues in this pandemic have been front and center. Whether it’s people who have less resources, people who have less ability to work from home, all of those things are going to be important. Our ability to provide testing and masking in those contexts will hopefully help us to address some of the equity issues which inevitably will emerge as we go deeper into the surge.

Do you think the difficulty in finding tests, whether it’s because people can’t afford to buy or find rapid tests or can’t get an appointment to get a PCR test, has led to undetected cases?

Oh, there’s no doubt. And you know, I sympathize because we’re making it difficult for people who are probably not feeling well and are probably worried. That is what everyone is living in right now. The best way to achieve the goals is to make sure that things are readily available and when they’re not, we risk continuing to fuel transmission because people just can’t do the things that they individually can do to help stop transmission. So yes, I think that is absolutely the case. 

What do you see as the burning questions about this virus that still need to be answered? 

This is a question that is hard to address. What we need to know more about is, what is different about the way this virus causes disease? What is the difference between those people who have immunity from prior infection and those people who have immunity from prior infection, plus vaccination, plus boosting, in terms of how this virus evades the immune system? 

“We’re seeing lots of people who are having exacerbations of their underlying conditions—of their diabetes, of their asthma.”

And ultimately, I think there’s a big difference of opinion among many of the scientists who are following this. There are some who believe that a benefit from this surge is that when you have more people who are infected who’ve also been vaccinated, they will develop more immunity to any future variant. And there are others who believe that that is not the case. I think we are going to want to follow that over time to understand what types of protections people have as we get out of the surge. 

If we look at what’s happening in other countries, what we know is that this surge will likely have a duration of four to six weeks. But we also know what we’re seeing in the hospital right now is that we’re not seeing people on ventilators in the same way that we have seen before. But, we’re seeing lots of people who are having exacerbations of their underlying conditions—of their diabetes, of their asthma, and other things. And I think we want to know more about how this virus causes illness and what it means after we get out of the surge as well.

From the numbers and data that you are seeing, do you think we are going to be in a better position in February? Or is the surge going to carry over into March?

I suspect that if our surge looks like other countries, and looks like the models that people are using, I think we will be out by February, this won’t go into March. I think all of that depends on the things that we do right now. We can still do a lot to try to make sure that the surge isn’t associated with the hospitals being full. But it does look like, most likely, we’re riding a huge wave right now in January that’ll be down in February and that by March we will be talking about what we do next. 

What is the pandemic endgame now that we are nearly two years into this?

“I don’t think we’re going to have a magic ‘ring the bell’ and the pandemic is over.”

There are some people who think that we are going to be at a place where there will be a lot of immunity after omicron that will protect us from other things. That will not lead to an end to the pandemic but will lead to more protection in the next thing. There are others who don’t think that’s the case. When we talk about the pandemic ending, I don’t think that’s the goalpost. What we want to be doing is trying to figure out how we have as few surges as possible, that we’re all as protected as possible and have the least disruptions like we’re having now. That’s most likely what we’re looking for. I don’t think we’re going to have a magic “ring the bell” and the pandemic is over. We are going to look at not having these massive surges anymore in cases and hospitalizations, and we figured out how to protect most of the population. There’s a difference of opinion whether omicron will lead us closer to that stage or whether, you know, we’ll still have to keep a watchful eye on the next variant.

Azucena Rasilla reports on arts and the community for The Oaklandside. Email: azucena.rasilla@gmail.com.