Low Viral Load, Surface Spread, and Immunity
Surface spread matters — don’t wait for the CDC to change its mind, again
Thanks for emphasising this point, that low viral loads can protect a mask user even if the virus does pass through a mask. The usefulness of masks has turned the political circle. It’s unfortunate that messages about surface spread are now creating confusion where none previously existed.
Same principle as social distancing
The role of masks and surface hygiene in preventing transmission is the same principle as social distancing — in that any acquired viral load would potentially be light. It can’t be guaranteed to be zero.
I wrote a post about this in April here are some references which also support your piece:
A higher viral load is associated with a higher severity illness that you will suffer. For example, with HIV, “ viral load monitoring predicts the deaths of HIV/AIDS patients” [BMC Infection diseases 2019].
Recent research found the same to be valid for COVID-19 — “The mean viral load of severe cases was around 60 times higher than that of mild cases, suggesting that higher viral loads might be associated with severe clinical outcomes” [The Lancet, March 19, 2020].
The researchers the Lancet publication above concluded: “Overall, our data indicate that similar to SARS in 2002–03, patients with severe COVID-19 tend to have a high viral load and a long virus-shedding period. This finding suggests that the viral load of SARS-CoV-2 might be a useful marker for assessing disease severity and prognosis”
Does it take — how many — just 100 virus particles?
The challenge is that “Scientists don’t yet know what that “minimum infectious dose” is for COVID-19, but they presume it’s around a hundred virus particles. After we are infected (by the initial dose) a virus replicates in our body’s cells.”
It’s that latter statement that interests me more at the moment — that “they presume that it is around one hundred virus particles”.
Not spread from touching — really?
At the moment there’s a bandwagon led by the CDC claiming that Covid19 does “not spread easily from touching surfaces”.
I don’t believe that for a second.
The CDC also claimed until relatively recently that masks weren’t effective — not for supply chain reasons, but that masks not protective against the spread of coronavirus (see below where I predicted in March that they would reverse this advice).
CLARITY - Masks Reduce Your Chance Of Getting And Giving Coronavirus
The facts are unambiguous, and you can make your own mask
As one of the people who commented on your post said — “I don’t know why this is so hard to understand?” There is one reason, actually. It’s because the people who are experts on this are the Japanese and the Chinese.
There is still a systemic bias against Asian research — and especially medicine — throughout the West. The pandemic has brought what was often unconscious bias and surfaced it (aided and abetted by the leader of the world’s greatest democratic power).
There is a vast trove of Japanese research on face masks.
While there is significant recent work on masks stopping the outward projection of microdroplets, the majority is about inbound transmission. This is because of the hayfever epidemic which started in Japan about 3 decades ago. Japanese masks are the best in the world at keeping pollen out.
Surfaces and touch spread germs, including viruses
The control of contact transmission is engrained in the Japanese lifestyle. Children learn from a young age how to wash their hands properly. They are disciplined in this by their parents and also by their teachers in primary school.
The discipline incorporates the core value of responsibility to others in the Group — whether that group is school, work, or neighbourhood.
The Japanese also practice many other ways of life which specifically separate potentially contaminated surfaces from clean surfaces:
- Changing their shoes at the door, and wearing house slippers.
- Changing their house slippers before entering the toilet or bathroom, and using specific slippers inside those areas.
- Having different kitchen cloths for different purposes e.g. clean surfaces, pots and pans, wiping the table clean after eating etc.
Some commentators say that these cultural practices are why Covid hasn’t been too troubling in Japan, despite a woefully inept response to the crisis from the central government.
My conclusion is that germs, viruses and surfaces matter. I have a much higher regard for the lessons of a couple of thousand years of cultural learning than the politically-correct advice of the CDC.
If surfaces didn’t matter we wouldn't need to wash our hands
The current advice from the CDC is that washing our hands matters, as does social distancing. I’m not sure why washing our hands matters if surface contact does not matter?
The CDC also has advice about removing a mask, and not touching the front surfaces. Why does not touching the front surfaces matter if surface-transmission is negligible?
The Japanese practice careful mask removal, they have demonstrations on TV. They even emphasis not to place your mask on surfaces around your house — dispose of it carefully. That’s because of surface contamination and potential transmission.
Is it sensible to go to gym wearing a mask, but to not wash your hands afterwards? No, because surface transmission matters.
The only question is about viral load, not whether surface transmission is negligible
The question boils down to viral load.
If you have touched the products in the supermarket, the handle of the supermarket trolley, pushed open a door, handled change from the cashier, and grabbed your full mask with your hands when you got back home, do you have a sufficient viral load to be dangerous?
Scientists presume that it takes about 100 active virus particles to infect us. A coronavirus, is on average, 0.125 microns in diameter. 100 of them amount to a speck 12.5 microns laid end to end — that’s 12.5 millionths of a metre.
Everything about 100 virus particles is absolutely minute — an infinitesimal speck of biological matter.
A carrier — for example, the asymptomatic shopper in front of you — could have sprayed out millions from the edge of their poorly fitting mask onto the self-serve checkout that you are about to use. If just 0.0001% of those remain alive for the next 5 minutes then you are in a red hot infection zone.
It seems to me that by saying that surface transmission is unlikely the CDC is sending the same mixed signals as President Trump deliberately sent about masks. How has that worked for the USA?
I want to know that people are cleaning common surfaces, and washing their hands, and paying attention to minimising their transmission to me.
Although you may be asymptomatic if you pick up a light load from surface contact, your parents and grandparents may not get off so lightly.
Surface spread matters. Don’t wait for the CDC to change its mind — again.