Masks for asymptomatic people?

Interesting info from WHO:

How do you know if you’re asymptomatic or presymptomatic? You don’t, yet some studies put the percentage of people who spread before symptoms at around 40%.


So I don’t want to argue against WHO (it seems this is a bit of a nuance from their earlier statements to wear masks in public), but as we discussed, in Sweden a big part of the mortality is from the nursing homes. Per this article below, the nursing home staff didn’t wear masks unless there was reason to believe someone was infected. That seemed to raise the risk of transmission in the elderly.

The agency’s advice to those managing and working at nursing homes, like its policy towards coronavirus in general, has been based on its judgment that the “spread from those without symptoms is responsible for a very limited share” of those who get infected.

Its advice to the care workers and nurses looking after older people such as Bondesson’s 69-year-old mother is that they should not wear protective masks or use other protective equipment unless they are dealing with a resident in the home they have reason to suspect is infected.

Otherwise the central protective measure in place is that staff should stay home if they detect any symptoms in themselves.

“Where I’m working we don’t have face masks at all, and we are working with the most vulnerable people of all,” said one care home worker, who wanted to remain anonymous. “We don’t have hand sanitiser, just soap. That’s it. Everybody’s concerned about it. We are all worried.”

“The worst thing is that it is us, the staff, who are taking the infection in to the elderly,” complained one nurse to Swedish public broadcaster SVT. “It’s unbelievable that more of them haven’t been infected. It’s a scandal.”

It’s certainly an evolving situation, but as we open up again, the use of face masks sounds urgent. Based on the information that the potential for airborne spread increases with singing, our church, which opened last week, required that everyone wear a mask on entering and when singing. It went quite well. It seems to be a protection to the most vulnerable among us.

1 Like

The problem is that people conflate presymptomatic, paucisymptomatic, and “truly asymtomatic.” Truly aysmptomatic cases are rare. What is not rare is people having significant viral shed before they come down with serious symptoms. What is not rare is people mistaking symptoms for allergies or PMS or a hangover and not realizing they are symptomatic. The applicable point of the study as I understand it was to say that contact tracing should focus on people who came down with symptoms, even if they were mild, not people who test positive but are “truly asymptomatic.”

The point is definitely not “If you don’t have symptoms, masks are useless!” They are perhaps not necessary for the very rare “truly asymptomatic” person. They are still needed for the presymptomatic or mildly symptomatic (but chalking it up to other issues) kind of people. Which are not rare.

A study in April found that viral shedding – when people may be able to infect others – could begin two to three days before symptoms appeared. In addition, the US Centers for Disease Control and Prevention estimates in planning scenarios that 40% of coronavirus transmission is occurring before people feel sick.

“These patients weren’t asymptomatic,” Juthani said. Rather, they were “spreading disease before becoming symptomatic.”

Overall, “these findings suggest that if we quarantine and contact trace symptomatic people, we can make a significant dent in the pandemic,” Juthani said.

Making this distinction between asymptomatic and pre-symptomatic infections remains important – but also between “paucisymptomatic infections,” which refers to having atypical or very mild symptoms, Babak Javid, a principal investigator at Tsinghua University School of Medicine in Beijing and consultant in infectious disease at Cambridge University Hospitals, said in a written statement distributed by the UK-based Science Media Centre on Monday.

“Detailed contact tracing from Taiwan as well as the first European transmission chain in Germany suggested that true asymptomatics rarely transmit. However, those (and many other) studies have found that paucisymptomatic transmission can occur, and in particular, in the German study, they found that transmission often appeared to occur before or on the day symptoms first appeared,” Javid said in the statement.


I thought it was promising, but as others have said, you don’t know if you’re asymptomatic or if you just haven’t developed symptoms yet, in which case you are v contagious, so still best to err on the side of caution.

But it makes sense, that truly asymptomatic people aren’t spreading it. Because they aren’t coughing or anything to release droplets.

1 Like

I’m still not sure what the WHO representative meant, but they seem to be walking it back now.

1 Like

I think it has more to do with the viral loud of the respiratory droplets then the fact that they aren’t releasing them. Talking, singing, and breathing can release respiratory droplets.

1 Like

True! Brief momentary lapse of brain.

Maybe, or maybe what makes them asymptotic also inhibits the spread of the virus in their system which limits their potential for spreading the disease.

At this point we don’t know.

What we do seem to be realizing is that contact tracing shows asymptotic people are a minimal threat to others.

Of course, we could all cower at home fearing for our safety and not interact with anyone, but society would die.

I think you’re really going to like the piece we are putting out tomorrow.

Thanks for the heads up!

I am eclectic in my likes.

My comment may have been a little sarcastic, so I apologize in advance. haha

Of course, everyone is asymptomatic until they aren’t. Obviously, the story may be different for pre-symptomatic or minimally symptomatic people. Lots of people go to work with coughs and runny noses or have done so in the past, especially those who may not get generous paid time off.


I was recently referred to this Cidrap podcast where a Dr. Osterholm is interviewed. He is somebody who attempts to simply “follow the science” even if doing so seems to lead in unpopular directions (which is the case here). And according to him (as of June 2 when this aired) science has failed to demonstrate any substantial efficacy of masks to prevent the spread of COVID. He does go on at length at first (taxing my patience as a listener, while he debunks what we already knew: establishing that masks are more to protect others - not so much the wearer.) But then in listening on, he does eventually get to that and claims that there is no solid science or research demonstrating the efficacy of masks (of the non N95 sort) in protecting others either. Quick caveat to maybe help diffuse some anticipated tension here - he issues lots of disclaimers that he is not anti-CDC and does have an established history of supporting them as well as challenging them. He also says that despite what he is discussing, he himself chooses to wear a mask in public just because he doesn’t want to make others uncomfortable, and wants to be sensitive to expectations in this regard. So even he doesn’t want his message to be used as political fodder.

But the problem (as he sees it) remains that masks only stop a small percentage of the aerosolized droplets that we issue, and so the problem is that people may be lulled into a false sense of security by having masks on, and may then make poor decisions in other regards. I.e. (I’ll feel better going to this crowded, non-distancing event with lots of strangers because … at lease we’ll have masks on.) So he is concerned that we’ll lean more heavily on mask wearing than what science can warrant. I also did note that he never claimed (I don’t think - I only listened once and it is rather tedious) that science had shown masks to not be effective. It had merely failed to demonstrate that they were. So there could be some common sense still in play too. Even if something turns out to be only 5% effective rather than 50% effective, 5% would still be something. [I just made up those last numbers for rhetorical purposes here - nobody quote them beyond this.]

In any case, while he may be unpopular because this will be perceived as swimming against laudable cultural exhortations to attend to each others’ health, is he nonetheless correct about the current state of the science?

Small is better than none like you said.

That isn’t a problem with masks but public health education I’d say.

I’m not so sure about this, but hopefully we have better evidence soon.

Some recent possible things to consider:

1 Like


Another factor, besides public health education, is that people have different risk tolerances and different perceptions of what is appropriate and important.

When a person pulls up in front of gas station on a trip to go to the restroom and sees people streaming in and out of the store, with no one wearing a mask, the thought comes up: do I want to appear a part of the tribe, or do I want to be an outsider?

This happened to me recently on a road trip to see family.

Yeah that is a pretty big factor. I felt super awkward when I went to church and was the only person out of 3 dozen or so.


That impulse, which I do not share, explains quite a bit of the deplorable state of the world. Do people strive from infancy to attain and never exceed an intelligence of 100? I think it has become so bad in some democratic countries that people prefer to elect a leader of their own level of intelligence rather than someone smarter. What a way to run a country! It is not that intelligence is the most important thing, such as that which makes us human or something. I frankly think it is so basic – an ability to follows rules – that it is built in the very fabric of the universe. BUT, there are some things and occupations where it is important. Do you really want a doctor with mediocre IQ operating on you?

So am I worried that I will not appear a part of the tribe by going in a store wearing a mask? No, I am not! I will never aspire to be anything other than who I am, and that includes smart and considerate enough to take precautions that I do not become a disease vector that brings about the death of somebody’s grandmother! It also includes not wasting a single thought or feeling on judging other people for not doing the same as me. I will leave all that nonsense to the barbarian hordes.


I don’t think wanting to “fit in” and be similar to others extends to everyone having the same IQ. And I don’t think IQ is a choice.

I am surprised that you would think the two are parallel.

But you have demonstrated with this example that just because people have a higher IQ doesn’t mean they have to act accordingly. And besides the truth is that you lose what you don’t use. Because of this, things are not so simply divided into what you choose and what you have no choice in. Most abilities are not simply a matter of innate capacity but also what you choose to develop. Yes there are innate limits on development, but that doesn’t mean you reach those limits without making a choice to put in the work that reaches such limits.

“Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone.” -Colossians 4:6

This is a place for gracious dialogue about science and faith. Please read our FAQ/Guidelines before posting.