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COVID-19 is one of the few serious diseases that can transmit when the carrier is asymptomatic. That could be a credible reason why a potential lab leak went unnoticed for long enough to begin uncontrolled community spread.

>>cowmoo+(OP)
> COVID-19 is one of the few serious diseases that can transmit when the carrier is asymptomatic.

Is this actually true? It is certainly not true for HIV, and of course is not relevant to diseases like Zika that are transmitted by mosquitos.

Edit: I found the answer to my own question: https://www.kff.org/infographic/ebola-characteristics-and-co... (see second bullet point). Given that this lists Hep C, HIV, Influenza, Malaria, Polio, and Tuberculosis as possible to transmit while asymptomatic, I'd say "COVID-19 is one of the few serious diseases that can transmit when the carrier is asymptomatic." is most definitely false.

>>hn_thr+c2
I can clarify it: COVID-19 is just about the only serious respiratory disease that undergoes rapid exponential spread and is transmissible while asymptomatic. That's a lot of qualifiers, but it makes for a uniquely scary pandemic threat.

>>hn_thr+c2
As always, it is not a 1-0 situation, but a question of degree.

You can catch flu from an asymptomatic person, but Covid has a much higher reproduction factor. During the winter lockdown in England, regular flu was completely eradicated - literally not a single case was detected in entire England [0]. At the same time, Covid was still spreading happily. The measures that stopped flu in its tracks only slightly inconvenienced SARS-Cov-2.

Covid is simply too good at spreading, compared to other similar diseases.

(As an analogy: I can swim, Michael Phelps can swim, we can both call ourselves swimmers, but we are not really comparable.)

[0]https://www.independent.co.uk/news/health/flu-cases-covid-en...

>>cowmoo+(OP)
CNN sold us on asymptomatic spread but it’s actually highly unlikely: https://www.nature.com/articles/s41467-020-19802-w

>>hn_thr+c2
Why is Malaria in the list?

>>mrfusi+Ah
I personally know people who went to a party and got sick from an asymptomatic person.

>>tasssk+um
Malaria can be (very rarely) transmitted through blood transfusions.

https://www.cdc.gov/malaria/about/us_transmission.html

>>geoduc+er
Why was this down voted?

>>fuzxi+RC
Or sharing needles! There's a small outbreak in Newark of injection drug users that's one of my favorite "Weird epidemiology papers" for journal clubs.

>>mrfusi+Ah
I've seen this study shared around anti-vaxer groups trying to claim that asymptomatic spread is unlikely. But this study does not prove that at all. They screened 10 million people with no symptoms, and found 300 asymptomatic cases. Then they re-screened 1200 contacts of those cases and didn't find any more cases that they missed. This doesn't prove that asymptomatic spread is unlikely. It proves that the incidence of SARS-CoV-2 when they did the screening was very low, and that 100% of the cases they found were asymptomatic. I'd be careful to draw conclusions from just one Chinese study, but if anything, this study suggests the opposite of what you're claiming.

>>geoduc+HU
You really have tabs on all the innumerable factors involved in a scenario where someone goes to a party and later becomes infected - and pinpoint the reason ?

>>yosito+NB1
I can’t quite follow the line of reasoning here. Can you simplify or rephrase?

(Also nice touch to question the credibility by associating it with anti vaxxers)

That’s by no means the only study though. Here’s a meta-analysis of 54 studies (link to paper is in article)

https://alachuachronicle.com/university-of-florida-researche...

>>mrfusi+no3
> I can’t quite follow the line of reasoning here. Can you simplify or rephrase?

I was pretty clear, and so was the original study you linked from nature.com. If you can't follow the reasoning of something that simple, should anyone take your claims to be coming from someone who knows what they're talking about?

From the second meta-study you linked:

> We found significantly higher secondary attack rates from symptomatic index cases than asymptomatic or presymptomatic index cases, although less data were available on the latter. The lack of substantial transmission from observed asymptomatic index cases is notable. However, presymptomatic transmission does occur, with some studies reporting the timing of peak infectiousness at approximately the period of symptom onset.

They state very clearly that though their analysis showed a lower secondary attack rate from asymptomatic index cases (0.7-4.9%), they have limited data from which to draw that conclusion, and that presymptomatic transmission does occur. Which means, you can catch SARS-CoV-2 from someone who doesn't know that they're sick.

That's according to the study you linked, and it's far from the claim you made that asymptomatic spread is "actually highly unlikely".

>>vixen9+bC1
At the party, there were 42 people present. 16 got sick. In many cases husbands got sick first, then wives. All of these are in a close social network (they either work together, or are married to an employee) - so keeping tabs on each other is very likely. Many of them were socially distancing before hand (I can attest to 4 of them, directly) - so external infections are unlikely, but possible.

Due to the timing, the general consensus is that the husbands contacted the disease from one male (close hugging or extended talking) and then gave it to their wives that night.