Asymptomatic Spread Rare… as in Zero?
The right side of the American Internet has been discussing a study published in Nature in November, emphasizing this finding:
No new symptomatic cases and 300 asymptomatic cases… were identified. There were no positive tests amongst 1,174 close contacts of asymptomatic cases. 107 of 34,424 previously recovered COVID-19 patients tested positive again…
Many, like Sundance on The Last Refuge, have taken this as definitive proof that asymptomatic spread simply doesn’t happen. If that’s the case, it requires a couple more steps to substantiate. However, those steps don’t justify the limited reportage and debate about these questions.
Note that the above paragraph involves a study of data at the tail end of COVID’s sweeping through Wuhan, China. The illness was petering out, which is surely relevant to transmission rates.
Another article in Nature from around the same time looked at the data from earlier in the Wuhan cycle, and the conclusion is quite different. Both those who were pre-symptomatic and those who were asymptomatic were contagious, although the latter were less so. Read through the report, however, and review the charts, and a question emerges that doesn’t seem to have received sufficient attention: How in the world can they claim to know exactly who caught the disease from whom?
You can know that Subject A tested positive and had no symptoms. You can also know that Subject A interacted with Subject B and that Subject B tested positive after Subject A. What you cannot know with certainty was whether Subject B already had the disease before Subject A was tested or Subject B picked up the virus from somebody not in the study.
This brings us back to the study quoted above. In that case, the virus was largely absent from the region, with no known symptomatic cases. The only known cases were asymptomatic, and they didn’t infect a single close contact whom researchers could find.
To be sure, we should adjust our response to this finding for the fact that the region was at that point post-pandemic (at least reportedly), but it’s still deserves more attention. As my fellow conservatives are pointing out, asymptomatic spread is the core rationale for putting ourselves into martial-law lite, greatly restricting our freedoms, so it’s important for it to be continually evaluated and debated.