Asymptomatic transmission may be over 100 times higher than symptomatic transmission. Someone without symptoms remains contagious for a minimum of 7 to 8 days, up to as many as 20 days!
I assume that 100 means the asymptomatic person will infect 100 times more people than the symptomatic person due to behavior differences. That means there is an opportunity to cut COVID transmission by a factor of 100 if testing could be made routine for everybody whether they feel sick or not. I have heard that PCR tests can be just as effective when only the mouth is swabbed. If PCR tests could be free and the results processed rapidly then the spread could be reduced a lot.
It would also be interesting to know the probability of being asymptomatic given an infection exists and the raw contagiousness of asymptomatic people versus symptomatic people when their behaviors are the same. It seems to me that a person with symptoms is surely more contagious, but maybe that is wrong.
(May 2021) After 13 days from a positive RT-PCR test, 144 patients underwent follow-up RT-PCR testing. 113 (78%) tested positive for SARS-CoV-2. Of those that tested positive, twenty-one (18.5%) were asymptomatic and 92 (81.5%) were symptomatic.
"Asymptomatic individuals and symptomatic patients did not show any significant differences in the mean Ct values of the E (31.15 vs 31.43; p>0.99), RdRp (32.26 vs 32.93; p=0.92) and N (33.05 vs 33.28; p>0.99) genes."
Conclusion "Approximately one-fifth of the individuals without severe symptoms were asymptomatic, and their viral loads were comparable to those in symptomatic patients. A large proportion of mildly symptomatic patients with COVID-19 or asymptomatic individuals with SARS-CoV-2 showed persistent positive upper respiratory RT-PCR results at follow-up."
"Higher viral loads in asymptomatic COVID-19 patients might be the invisible part of the iceberg" (November 24, 2020)
"Viral loads of asymptomatic patients were found to be significantly higher (p = 0.0141) when compared with symptomatic patients. Viral load had a significant negative trend with increasing age. A significant decrease in viral load was observed with increasing disease severity."
Conclusion
"In conclusion, this study demonstrates that asymptomatic patients have higher SARSCoV-2 viral loads than symptomatic patients and unlike in the few study in the literature, a significant decrease in viral load of nasopharyngeal/oropharyngeal samples was observed with increasing disease severity."
I want to thank you for your labour. We are in the midst of another wave here in New Zealand, the government recently moved to a 5 day isolation period (no longer legally mandated though) and remove masks. It's maddening to say the least. Your newsletter is one of the key ways I stay informed.
Thank you for the comment. It makes me so sad to see where you are sending it from.
New Zealand is a country that had the longest sustained and successful mitigation effort. They protected their citizens, but that appears to have ended. We know that a recommended 5-day isolation period is not effective. It looks like they were convinced to follow the CDC's lead.
Big mistake. Are they requiring quality N-95 type masks in healthcare settings at least? Have they improved the ventilation and air filtration in schools or hospitals? I wish the answer would be yes, but I would be surprised if they did.
Unfortunately they've even removed mask in hospitals and age care settings. Surgical masks are still provided but not legally required and as you can imagine, covid is hitting both staff and patients. There's no coordinated air quality efforts apart from school classrooms having 1 air purifier (I pushed for additional one in my daughter's classroom) It's deeply disappointing and hard to grasp given how well we did earlier in the pandemic.
Hi TACT...Beautiful picture to lead off this article. The spectrum of color is amazing.
Now...on to business...here is a research article you might find interesting. (Try to get past the questionable ethics of INTENTIONALLY infecting participants with SARS-CoV-2 as challenging as that is to do) Here is the money quote:
"Very few emissions occurred before the first reported symptom (7%) and hardly any before the first positive lateral flow antigen test (2%)."
The photo was taken just a few days ago. The fall colors are beautiful! Thanks!
The first things that we have to acknowledge is the age group being 18 to 30 years old, and that it doesn't reflect any of the Omicron variants, which have higher replication rates and higher viral loads.
The thing that stands out is that most were infectious for 10 to 14 days. This, once again, shows that the CDC 5 day isolation guidance is ridiculous and dangerous.
Did you look at the supplemental? Very interesting breakdown by each participant. They also found SARS-CoV-2 on surfaces, hands and the air.
I assume that 100 means the asymptomatic person will infect 100 times more people than the symptomatic person due to behavior differences. That means there is an opportunity to cut COVID transmission by a factor of 100 if testing could be made routine for everybody whether they feel sick or not. I have heard that PCR tests can be just as effective when only the mouth is swabbed. If PCR tests could be free and the results processed rapidly then the spread could be reduced a lot.
It would also be interesting to know the probability of being asymptomatic given an infection exists and the raw contagiousness of asymptomatic people versus symptomatic people when their behaviors are the same. It seems to me that a person with symptoms is surely more contagious, but maybe that is wrong.
(May 2021) After 13 days from a positive RT-PCR test, 144 patients underwent follow-up RT-PCR testing. 113 (78%) tested positive for SARS-CoV-2. Of those that tested positive, twenty-one (18.5%) were asymptomatic and 92 (81.5%) were symptomatic.
"Asymptomatic individuals and symptomatic patients did not show any significant differences in the mean Ct values of the E (31.15 vs 31.43; p>0.99), RdRp (32.26 vs 32.93; p=0.92) and N (33.05 vs 33.28; p>0.99) genes."
Conclusion "Approximately one-fifth of the individuals without severe symptoms were asymptomatic, and their viral loads were comparable to those in symptomatic patients. A large proportion of mildly symptomatic patients with COVID-19 or asymptomatic individuals with SARS-CoV-2 showed persistent positive upper respiratory RT-PCR results at follow-up."
https://thorax.bmj.com/content/76/1/61?fbclid=IwAR2Ngc7tCsdDbntcxAcVrmOjCIio2jLI-fCnkz7asplMqM5ck-CzziuYDJk
"Higher viral loads in asymptomatic COVID-19 patients might be the invisible part of the iceberg" (November 24, 2020)
"Viral loads of asymptomatic patients were found to be significantly higher (p = 0.0141) when compared with symptomatic patients. Viral load had a significant negative trend with increasing age. A significant decrease in viral load was observed with increasing disease severity."
Conclusion
"In conclusion, this study demonstrates that asymptomatic patients have higher SARSCoV-2 viral loads than symptomatic patients and unlike in the few study in the literature, a significant decrease in viral load of nasopharyngeal/oropharyngeal samples was observed with increasing disease severity."
https://link.springer.com/article/10.1007/s15010-020-01548-8
I want to thank you for your labour. We are in the midst of another wave here in New Zealand, the government recently moved to a 5 day isolation period (no longer legally mandated though) and remove masks. It's maddening to say the least. Your newsletter is one of the key ways I stay informed.
Thank you for the comment. It makes me so sad to see where you are sending it from.
New Zealand is a country that had the longest sustained and successful mitigation effort. They protected their citizens, but that appears to have ended. We know that a recommended 5-day isolation period is not effective. It looks like they were convinced to follow the CDC's lead.
Big mistake. Are they requiring quality N-95 type masks in healthcare settings at least? Have they improved the ventilation and air filtration in schools or hospitals? I wish the answer would be yes, but I would be surprised if they did.
Unfortunately they've even removed mask in hospitals and age care settings. Surgical masks are still provided but not legally required and as you can imagine, covid is hitting both staff and patients. There's no coordinated air quality efforts apart from school classrooms having 1 air purifier (I pushed for additional one in my daughter's classroom) It's deeply disappointing and hard to grasp given how well we did earlier in the pandemic.
Hi TACT...Beautiful picture to lead off this article. The spectrum of color is amazing.
Now...on to business...here is a research article you might find interesting. (Try to get past the questionable ethics of INTENTIONALLY infecting participants with SARS-CoV-2 as challenging as that is to do) Here is the money quote:
"Very few emissions occurred before the first reported symptom (7%) and hardly any before the first positive lateral flow antigen test (2%)."
https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(23)00101-5/fulltext
The photo was taken just a few days ago. The fall colors are beautiful! Thanks!
The first things that we have to acknowledge is the age group being 18 to 30 years old, and that it doesn't reflect any of the Omicron variants, which have higher replication rates and higher viral loads.
The thing that stands out is that most were infectious for 10 to 14 days. This, once again, shows that the CDC 5 day isolation guidance is ridiculous and dangerous.
Did you look at the supplemental? Very interesting breakdown by each participant. They also found SARS-CoV-2 on surfaces, hands and the air.
When it comes to the Center for Disease Circulation (CDC), you will rarely do wrong if you do the OPPOSITE of their recommendations.