Monkeypox Virus Credit CDC PHIL
#16,949
Two years ago - after repeated exported cases of Monkeypox turned up in the UK, Israel, and Singapore - the Bulletin of the World Health Organization carried a report called Modelling human-to-human transmission of monkeypox, where the authors reassuringly stated:Monkeypox is not considered contagious during its incubation period and asymptomatic monkeypox infection has not been documented.
Of course, `has not been documented' isn't the same thing as `never happens', particularly when you are talking about a poorly investigated disease like Monkeypox.
As we've seen with COVID-19, Zika, Ebola, and a great many other viral infections - under closer examination - `conventional wisdom' is often subject to change.
The rapid spread of the Monkeypox virus outside of endemic African nations has exceeded all expectations, which has led many researchers to question past assumptions.
More than two months ago, in Atypical Monkeypox Presentations, we looked at some of these unknowns, including a statement from the CDC which left the door for asymptomatic infection slightly ajar:
Unknown/Still learning: Contact with people who are infected with monkeypox but have no symptoms (We think people with symptoms are most likely associated with spread, but some people may have very mild illness and not know they are infected).
While we don't have any data on the transmission of MKPV from asymptomatic individuals - yesterday researchers at the Bichat-Claude Bernard Hospital in Paris published a letter that documented the detection - via PCR-tested anal swabs from 200 asymptomatic MSM visiting a clinic - of the virus in 6.5% (n=13) of the tests.
While two of these 13 eventually reported symptoms, this suggests that asymptomatic carriage of the virus is not only possible, it may even be fairly common.
Due to it length, I've only posted the link and a brief snippet. Click it to read the report in its entirety.
Letters 16 August 2022
(excerpt)
This report documents positive MPXV PCR results from anal samples in asymptomatic MSM. Whether this indicates viral shedding that can lead to transmission is unknown. If so, the practice of ring postexposure vaccination around symptomatic persons with probable or confirmed MPXV infection may not be sufficient to contain spread. Recent French recommendations have advised vaccination for all MSM with multiple partners (5).
You'll find an accompanying Editorial by Stuart N. Isaacs, MD on the letter.
Asymptomatic Infection? Another Reason to Consider Monkeypox a Disease of Public Health Concern
Although none of this tells us how much of an impact - if any - that asymptomatic carriage of the virus has on the spread of the virus = when combined with other reports (see EID Journal: Human Monkeypox without Viral Prodrome or Sexual Exposure, California, USA, 2022) - it raises concerns the virus may be more widespread - and therefore harder to contain - than many suspect.
