Thread by @fascinatorfun

Chinese couple, pre-symptomatic, attended church service in Singapore 19/1/20
Symptomatic 22/1/20

Another 2 people who attended the church service got CV19

So did a woman who attended a later church service but who sat where the Chinese couple had done bbc.co.uk/news/uk-528407…

Aggressive contact tracing in Singapore established that the disease transmits symptomatically. S Korea confirmed it although at the time, China was saying not so. Later a leaked Gov report suggested maybe 30% did.

The range of estimates of asymptomatic cases vary wildly.

Diamond Princess testing also suggested there were more asymptomatic than symptomatic passengers and that they spread the virus, altho’ I am not clear whether full follow up was carried out to establish how many were presymptomatic.

One of the unanswered questions is HOW much asymptomatic people spread the virus compared to symptomatic.

But they may be driving the pandemic, resulting in the fires never really being put out.

Certainly by mid February a Singapore Doctor who had also visited the @WHO said on Newsnight that this is what made it so deadly.

Too many countries had been preparing for symptomatic transmission like SARS.

Something different needed for COVID.

A definitive answer is needed.

To try to get an answer, scientists in Norwich are pushing for the population of the entire city to be tested.
"Asymptomatic cases may be the 'dark matter' of the epidemic," according to Prof Neil Hall.