Very excited to share our new preprint " #SARSCoV2 viral load dynamics, duration of viral shedding and infectiousness: a living systematic review and meta-analysis" #IDTwitter

A huge team effort screening and synthesising the accumulating evidence. 1/6 https://www.medrxiv.org/content/10.1101/2020.07.25.20162107v1

2/6 Main findings:
- In the upper respiratory tract (URT), mean duration of RNA shedding was 17 days (95% CI, 15.5-18.6), max 83d
- Shedding duration increases with age & severity of illness
- There were limited studies reporting shedding duration in sputum (n=7) and stool (n=13)

3/6 - High SARS-CoV-2 viral loads in URT are detectable in the first week, and peak viral load occurs at day 0-5
- In contrast, peaks in SARS-1 and MERS occurred at days 10-14 and 7-10 of illness
- Pts with SARS-CoV-2 are likely to be most infectious day 0-5 (3/6)

4/6 - No study to date has cultured live virus beyond d9 in URT despite high viral loads (VL)
- The success of isolation correlated with VL quantified by PCR
- No successful viral culture when VL< 10^6 copies/ml, Ct values >24 or >34
- Only 2 studies cultured live virus in stool

5/6 - Viral loads at the start of infection appear to be comparable in asymptomatic and symptomatic patients but most studies demonstrate faster viral clearance in asymptomatic individuals
- There are limited data on the shedding of infectious virus in asymptomatic individuals

6/6 We also reviewed all papers reporting viral dynamics and duration of viral shedding of SARS-CoV-1 and MERS-CoV and made comparisons.

This has been an enormous work, thanks to our fantastic team inc @DrToniHo @silverfoxdoc & many more, we will update this r/v 3monthly

And here is a fantastic lay summary of the main findings in one tweet: https://twitter.com/mastweiler8/status/1288471478745391104?s=20