Things to know about President Trump's coronavirus diagnosis, based on COVID-19 research to date.

1. When did Hope Hicks catch the virus?

Likely unknowable, but her symptoms offer some clues on the timing...

Hicks reportedly developed symptoms Wednesday evening (left, via @AP). https://apnews.com/article/virus-outbreak-donald-trump-health-archive-hope-hicks-7fece2838ff7a9bd91ccf5ac287348b3

COVID's incubation period—how long symptoms take to appear after exposure—ranges from 1-14 days, though most develop signs after 4-6 days. (: @ConversationUK)
https://theconversation.com/how-long-are-you-infectious-when-you-have-coronavirus-135295

Takeaway 1: Hope Hicks may have caught COVID-19 anytime between Sept. 16-29, but it was most likely last Thursday thru Saturday (Sept. 24-26).

2. Why did Hicks test+ before President Trump?

The WH hasn't released its COVID-19 protocol, but details appear in news reports.

Aides/anyone close to POTUS are tested every day (AP story ).

But Trump has publicly said he isn't ( @politico, July 21)
https://www.politico.com/news/2020/07/21/trump-tested-coronavirus-multiple-times-day-375957

That seems to be the case, given Trump/Melania weren't tested UNTIL AFTER Hicks was positive.

Alternatively, if Trump is tested every day too, then his viral load simply took longer to develop/become detectable.

Takeaway: WH was more likely to catch Hicks's case before Trump's.

3. Did President Trump catch COVID-19 from Hicks?

Unclear for a few reasons, but again her symptom onset offers clues.

COVID's most infectious period begins 1-3 days before symptoms arise. (: @ConversationUK) https://theconversation.com/how-long-are-you-infectious-when-you-have-coronavirus-135295

Scenario 1. So it's possible that Hicks was infectious by Sunday (Sept. 27), passed it to Pres. Trump early this week, and his viral load increased in time to test positive on Thursday.

OR

Scenario 2: Trump and Hicks were both exposed around the same time by a third person, but Hicks's case was symptomatic and Trump's was asymptomatic.

The viral loads for asymptomatic and symptomatic cases follow a similar progression early on. https://www.ecdc.europa.eu/en/covid-19/latest-evidence/transmission

OR

Scenario 3: Trump/Hicks were exposed around the same time by completely different people

Given POTUS and his cadre don't wear masks, don't social distance, and still shake hands in public despite high prevalence of asymptomatics...good luck with contact tracing the source.

Takeaway 3: Hicks was potentially infectious starting Sunday (Sept. 27). But she didn't necessarily give it to President Trump, and they could have caught it independently.

Given the White House's disregard for its own public health guidance, finding the source could be tricky.