An Estimated 86% Of SARS-CoV-2 Infections In China Undocumented Prior To Travel Restrictions

[Giraffe]

I seems that every week more physicians are expressing their doubts publicly. The following is from the website of a Swiss hospital specialized in infectiology.

Pioneering work barely noticed by the media

It is therefore not surprising that the publication by Li et al. passed us almost unnoticed. But the work published in the highly endowed "Science" has it all. The epidemiologists investigated the spread of COVID-19 in China and investigated how often the new infections were discovered. The methodology is sophisticated, it is based on calculations of contact probabilities and also includes mobility data and other complex information.

However, the result is told quite simply:

• Around 85% (82-90%) of all infections occurred without anyone noticing the infection
• About 55% of the undetected infected did infect other people

We have actually suspected this for a long time. Otherwise it would have been impossible to explain that the number of infections in China dropped to zero after a few weeks. Because with an immunity rate of less than 1% of the population, this cannot be explained (less than 100,000 people in Wuhan are affected by around 10 million people). It would not come as a surprise if further studies put the rate of silent infections even higher.

Full text link to study: Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV2)

 

[ecstatichamster]

Thank you. Reading it now.

 

[LeeLemonoil]

So if half of those unrecognized/unnoticed infected were also transmitters and we have data this Corona was already in Italy in October / November. Isn’t it very likely that a huge amount of worldwide population was already infected?

 

[S.Seneff]

Probably not many tested done prior to travel restrictions.

 

[Sucrates]

These types of theoretical papers should be taken for what they are. This, along with the recent paper out of the UK would be very encouraging if backed by real world evidence, until then it's best to assume doom.
Widespread and randomized antibody testing could answer those questions pretty clearly, I suspect we're in for more incompetence, politics and denial before that occurs.

 

[JudiBlueHen]

Excellent study - first comprehensive model I've seen so far.

 

[Giraffe]

So if half of those unrecognized/unnoticed infected were also transmitters and we have data this Corona was already in Italy in October / November. Isn’t it very likely that a huge amount of worldwide population was already infected?

Yes, this would be the conclusion, I think. And those who have already been infected are immune now.

Using the best-fitting model (Table 1 and Fig. 1), we estimated 13,118 (95% CI: 2,974–23,435) total new COVID-19 infections (documented and undocumented combined) during 10–23 January in Wuhan city. Further, 86.2% (95% CI: 81.5%–89.8%) of all infections were infected from undocumented cases. Nationwide, the total number of infections during 10–23 January was 16,829 (95% CI: 3,797–30,271) with 86.2% (95% CI: 81.6%–89.8%) infected by undocumented cases.

This means that in China during the period 10-23 January an estimated 14,506 people have been infected by undocumented cases. This implies that the virus was around for quite a while by that time, and tens of thousands had already been infected and were immune now. It's highly unlikely that it has not spread worldwide prior to travel restrictions in China; despite WHO still talking on 21 February about the "window of opportunity" narrowing.

So this would mean that the model calculation of London Imperial College is based on wrong assumptions, wouldn't it?

related thread: Covid-19 Models And Predictions

infection was assumed to be seeded in each country at an exponentially growing rate (with a doubling time of 5 days) from early January 2020

 

[LeeLemonoil]

@Giraffe

I heard Christian Drosten O-Ton / saying in radio news that he got contacted by various people in the meantime from German corporations mostly that have staff traveling to China a lot.
They, according to him described that they had massive flu-like occurrences and sich staff and their family in September/October last year. They asked him if thaf wouldn’t have been Covid already.
Sure, was his response and made them send serum examples of the affected.
He sais no traces of SARS-CoV2 in those Sera/Serums. He reiterated that Corona wasn’t in Germany before January

Let’s remember that. He puts his name on the line with that I think

 

[Giraffe]

@Giraffe

I heard Christian Drosten O-Ton / saying in radio news that he got contacted by various people in the meantime from German corporations mostly that have staff traveling to China a lot.
They, according to him described that they had massive flu-like occurrences and sich staff and their family in September/October last year. They asked him if thaf wouldn’t have been Covid already.
Sure, was his response and made them send serum examples of the affected.
He sais no traces of SARS-CoV2 in those Sera/Serums. He reiterated that Corona wasn’t in Germany before January

Let’s remember that. He puts his name on the line with that I think

Thanks.

That Drosten couldn't find antibodies in those samples would suggest that the sick ones were suffering from something else, which is to be expected statistically unless the number of samples is very large. Of the tests done today (only symptomatic people get tested, and only if they had close contact with a confirmed case) only 5% are positive. That means that 95% of the symptomatic people are not positive.

 

[S.Seneff]

Hundreds of severe pediatric COVID-19 infections in Wuhan prior to the lockdown
Zhanwei Du, Ciara Nugent, Benjamin J Cowling, View ORCID ProfileLauren Ancel Meyers
doi: Hundreds of severe pediatric COVID-19 infections in Wuhan prior to the lockdown
This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

Before January 22, 2020, only one pediatric case of COVID-19 was reported in mainland China. However, a retrospective surveillance study identified six children who had been hospitalized for COVID-19 in one of three central Wuhan hospitals between January 7th and January 15th. Given that Wuhan has over 395 other hospitals, there may have been far more severe pediatric cases than reported. There were six and 43 children out of 336 who tested positive for COVID-19 and influenza, respectively among all pediatric admissions during the 9-day period. By using this ratio in a detailed analysis of influenza surveillance data and COVID-19 epidemic dynamics (see Appendix), we estimate that there were 313 [95% CI: 171-520] children hospitalized for COVID-19 in Wuhan during January 7-15, 2020 (Figure). Under an epidemic doubling time of 7.31 days4, we estimate that there were 1105 [95% CI: 592, 1829] cumulative pediatric COVID-19 hospitalizations prior to the January 23rd lockdown, which far surpasses the 425 confirmed cases reported across all age groups, none of which were children under age 15. Children are strikingly absent from COVID-19 reports and limited data suggest that pediatric infections are overwhelmingly mild5. Thus, our estimates for hundreds of severe pediatric cases likely translates to thousands or even tens of thousands of mildly infected children, suggesting that the force of infection from children may be grossly underestimated and the infection fatality rate overestimated from confirmed case counts alone. This highlights the urgent need for more robust surveillance to gauge the true extent and severity of COVID-19 in all ages.

 

[LeeLemonoil]

I say it again in the might of this study: Deadly inflammation in elderly or severely sick is an evolutionary mechanism to protect the species. Mode viruses seem unable to really harm and overwhelm immunity of young humans.

They manage that with old and sick. To prevent them from adapting to human organism and „learn“ and mutate in the suspectible old and infirm hosts, heavy inflammation evolved. Either to kill the pathogen in a last ditch attempt or to die as the host and thereby kill the pathogen indirectly

 

[Giraffe]

Under an epidemic doubling time of 7.31 days, we estimate that there were 1105 [95% CI: 592, 1829] cumulative pediatric COVID-19 hospitalizations prior to the January 23rd lockdown, which far surpasses the 425 confirmed cases reported across all age groups, none of which were children under age 15.

Same study, different source:

Detection of Covid-19 in Children in Early January 2020 in Wuhan, China

This study showed that Covid-19 occurred in children, causing moderate-to-severe respiratory illness, in the early phase of the SARS-CoV-2 outbreak in Wuhan and was associated with ICU admission in one patient. None of the patients or their family members had had direct exposure to Huanan Seafood Wholesale Market (the initial location to which cases of Covid-19 were linked) or to one another.

This is only the numbers from Wuhan.

Given that the disease is overwhelmingly very mild in children, 1105 hospitalized children sounds huge.

Thus, our estimates for hundreds of severe pediatric cases likely translates to thousands or even tens of thousands of mildly infected children, suggesting that the force of infection from children may be grossly underestimated and the infection fatality rate overestimated from confirmed case counts alone. This highlights the urgent need for more robust surveillance to gauge the true extent and severity of COVID-19 in all ages.

 

[S.Seneff]

I don't know. Perhaps doctors are only in hospital in china ? Perhaps hospital need to make money so they "motivate" people to stay at least one night ?

 

[Hugh Johnson]

Same study, different source:

Detection of Covid-19 in Children in Early January 2020 in Wuhan, China

This is only the numbers from Wuhan.

Given that the disease is overwhelmingly very mild in children, 1105 hospitalized children sounds huge.

There are 1.3 billion people in China. That is literally one in a million.

 

[Giraffe]

There are 1.3 billion people in China. That is literally one in a million.

It's Wuhan, not China. And it's only children < 15 years hospitalized between January 7 and January 15. The figure is closer to 600 in a million.

 

[Giraffe]

I don't know. Perhaps doctors are only in hospital in china ? Perhaps hospital need to make money so they "motivate" people to stay at least one night ?

They stayed 5 to 13 days in hospital. One was admitted to ICU.

Why did you post the study in the first place?

 

[Giraffe]

A while ago Dr. Wolfgang Wodarg said something along the lines that it is silly to call SARS-CoV-2 "novel". The truth is that there has not been much research in the past: There was a bit of research 15 years ago, and there is research now, but in-between there was not much interest in corona viruses.

This study from Spain supports what he said.

Sentinel surveillance of SARS-CoV-2 in wastewater anticipates the occurrence of COVID-19 cases

"Unexpectedly, analysis of archival samples revealed the increasing occurrence of SARS-CoV-2 genomes in samples from January 15 to March 4, 2020 (Figure 1, panels D and E). Of note, SARS-CoV-2 was detected in sewage 41 days (January 15) before the declaration of the first COVID-19 case (February 25), clearly evidencing the validity of wastewater surveillance to anticipate cases in the population."

"Most COVID-19 cases show mild influenza-like symptoms (14) and it has been suggested that some uncharacterized influenza cases may have masked COVID-19 cases in the 2019-2020 season (11). This possibility prompted us to analyze some archival WWTP samples from January 2018 to December 2019 (Figure 2). All samples came out to be negative for the presence of SARS-CoV-2 genomes with the exception of March 12, 2019, in which both IP2 and IP4 target assays were positive."

..........


This is an article about another study:

COVID-19 origin: University of Calgary research shows SARS-CoV-2 may have been evolving slowly since 2013

"Scientists at the University of Calgary in Canada say that the novel coronavirus (SARS-CoV-2) may have been circulating amongst humans since at least 2013, though not the same variant that is responsible for the COVID-19 pandemic."