04-07-2020, 01:45 PM
New report from Wuhan; at the height of the epidemic there, they started testing the blood supply.
https://wwwnc.cdc.gov/eid/article/26/7/20-0839_article
The found four positive cases of viral RNA (I don't know if that blood would have been infectious, since you could also see RNA in cases where virions were killed and their RNA spilled into the blood). Still. The four cases were asymptomatic at the time of the blood donation.
Out of 2,430 blood donations obtained "by March 4", one was positive, indicating a prevalence of detectable RNA in the blood of .4% among asymptomatic individuals. They also retrospectively looked at nearly 5000 donations from December to January, and found one other detectable RNA in the blood.
Another pool of blood came from blood that had been removed from the pool because telephone follow-up with the donors found that they had fever (n = 33), and found two positive patients. So, these could be considered the pre-symptomatic patients.
Blood donation is not random, and the correlation between respiratory detectable virus and viral RNA in the blood is unknown (all four positives had positive throat swabs, but it is hard to tell what fraction of people with positive swabs would have had detectable RNA in the blood. but it does give you a sense of the prevalence of otherwise undetected cases, out of nearly 7500 total screened blood samples (.05%).
BC
https://wwwnc.cdc.gov/eid/article/26/7/20-0839_article
The found four positive cases of viral RNA (I don't know if that blood would have been infectious, since you could also see RNA in cases where virions were killed and their RNA spilled into the blood). Still. The four cases were asymptomatic at the time of the blood donation.
Out of 2,430 blood donations obtained "by March 4", one was positive, indicating a prevalence of detectable RNA in the blood of .4% among asymptomatic individuals. They also retrospectively looked at nearly 5000 donations from December to January, and found one other detectable RNA in the blood.
Another pool of blood came from blood that had been removed from the pool because telephone follow-up with the donors found that they had fever (n = 33), and found two positive patients. So, these could be considered the pre-symptomatic patients.
Blood donation is not random, and the correlation between respiratory detectable virus and viral RNA in the blood is unknown (all four positives had positive throat swabs, but it is hard to tell what fraction of people with positive swabs would have had detectable RNA in the blood. but it does give you a sense of the prevalence of otherwise undetected cases, out of nearly 7500 total screened blood samples (.05%).
BC