Profile picture
, 7 tweets, 8 min read
My Authors
Read all threads
1/ Presymptomatic transmission is one of the most complex parts of controlling the #covid19 epidemic.

Quantitative #covid19 viral loads have been found to be equally high in those with or without symptoms.

nejm.org/doi/full/10.10…
2/ This @NatureMedicine paper estimated presymptomatic #SARSCoV2 transmission as being responsible for nearly half (44%) of secondary cases.

nature.com/articles/s4159…
3/ A strategy that only focuses on those with symptoms is likely to fall drastically far behind in terms of curtailing transmission.

We need far more testing, likely sequentially a few times over the possible incubation period of 14 days in suspect cases

annals.org/aim/fullarticl…
4/ This can be especially difficult if secondary transmission is happening in the home w/ someone who is presymptomatic but near family for extended periods.

We need to quickly understand to what extent family-based clusters are driving US transmission.
washingtonpost.com/outlook/2020/0…
5/ Singapore, which had a resurgence of cases after having an initially strong response, has since begun what seems to be an efficient central isolation strategy w/ nearly 9 out of 10 #covid19 cases being centrally isolated.

straitstimes.com/singapore/9-in…
6/ Reducing the window b/w when a *high exposure event* occurred & *quarantine* of the suspect case will be critical to minimizing presymptomatic transmission.

Waiting for symptoms means 2-3 days of possible transmission.

nature.com/articles/s4159…
Cc @RanuDhillon @CarolineYLChen @BhadeliaMD @syramadad @FranciscoMarty_ @s_keshavjee @atheendar @IngridKatzMD @T_Inglesby @johnbrownstein @aetiology @marciacastrorj @JenniferSpicer4 @zeynep @megtirrell @carlzimmer @cshea4 @LauraSanthanam @jeremyfaust @cbpolis @AaronLBerkowitz
Missing some Tweet in this thread? You can try to force a refresh.

Enjoying this thread?

Keep Current with Abraar Karan, MD MPH DTM&H

Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

Twitter may remove this content at anytime, convert it as a PDF, save and print for later use!

Try unrolling a thread yourself!

how to unroll video

1) Follow Thread Reader App on Twitter so you can easily mention us!

2) Go to a Twitter thread (series of Tweets by the same owner) and mention us with a keyword "unroll" @threadreaderapp unroll

You can practice here first or read more on our help page!

Related hashtags

#covid19 #SARSCoV2

More from @AbraarKaran see all

Profile picture
Abraar Karan, MD MPH DTM&H
@AbraarKaran
THREAD on why I think the presymptomatic transmission period has made #covid19 especially difficult to stop.
-SARSCoV-1 viral loads peak ~5 days later & are higher in the lower respiratory tract compared to #SARSCoV2, which has a high level of shedding from the upper resp tract
-compared to influenza, in which people who are asymptomatic generally have lower viral loads in the upper respiratory tract & shorter duration of shedding than those w/ symptoms, the same does not seem to hold for #SARSCoV2

nejm.org/doi/full/10.10…

nature.com/articles/s4159…
Most of this is not new- we had suspicion (multiple articles in both @NEJM & @JAMA_current in *February* suggesting that we had asymptomatic & presymptomatic transmission), yet for some reason-likely lack of tests- our strategy has for quite a while focused on symptomatic cases
Read 5 tweets
Profile picture
Abraar Karan, MD MPH DTM&H
@AbraarKaran
THREAD on my new op-ed in WaPo

1/ I spent the last 2 weeks on clinical service in our emergency room #covid19 pod.

Caring for patients was tough, but it was even tougher knowing that sending them back home would likely mean infecting their families.

washingtonpost.com/outlook/2020/0…
2/ So many patients shared the exact same story- index case was a healthcare worker or other front line worker who got sick on the job. They tried to take care of themselves at home; got more ill; family tried to both avoid them/help them; family got sick as well.
3/ This was particularly devastating when it ended up that a son or daughter accidentally infected their parents, some of whom were old and had comorbidities, became critically ill, needing admission +/- a ventilator; some even dying within a couple of days. This was really hard.
Read 12 tweets
Profile picture
Abraar Karan, MD MPH DTM&H
@AbraarKaran
New study @NatureMedicine estimates that nearly half of #covid19 transmission occurs in the 2-3 days before any symptoms, & peak infectiousness may be close to the actual day that symptoms start.

nature.com/articles/s4159…
“Significant presymptomatic transmission would probably reduce the effectiveness of control measures that are initiated by symptom onset, such as isolation, contact tracing and enhanced hygiene or use of face masks for symptomatic persons.”
This is why rapid diagnostics & wide community testing of people who are symptomatic AND those who are pre-symptomatic or asymptomatic w/ exposure to known cases- is critical. If we have to wait for symptoms to start, we may get too far behind. #covid19
Read 4 tweets

Embed code for your website

×
Follow Us on Twitter!

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3.00/month or $30.00/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!