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by raphlinus·5y ago·view on hn ↗
The pro-disinformation comments here on Hacker News are entirely predictable, yet make me despair for humanity. I'd love a site where bad faith arguments are unwelcome, but heterodox opinions are encouraged, especially when supported with evidence and reasoning.

To stir things up, I'll give an example of such an opinion right now. Health organizations around the world are systematically lying to us about the basic reproduction number (R0) of the delta variant being astronomical (the figure of 8 is now commonly cited). Serious virologists[1] remind us that the evidence for such high estimates is thin and not based on biology; changes in human behavior, combined with antigenic drift (as observed regularly in influenza without the inference of constantly climbing R0 values) can explain what we're seeing.

It is likely that the R0 value is somewhat higher than the ancestral strain, but a value of 8 is an extraordinary claim which requires extraordinary evidence. And that we do not have, in spite of preprints that show higher viral load[2].

I use the word "lying" but it's most likely this is as much self-delusion than a conscious choice to mislead. But the motivation is very strong: the "delta variant is scary" narrative is much more compelling than "Covid is still dangerous," and indeed is likely contributing to increased vaccination rates.

I'll also note that what I just said would likely trip the "misinformation" filters at the big Internet providers, as it contradicts "medically reliable sources" [WP:MEDRS]; these high estimates are being published by major medical and scientific organizations. It is interesting to note, though, that the official info from the CDC[3] is less out there than the astronomical estimates being breathlessly published by the press. The CDC page says "50% increased transmission" for delta, based on a paper from the UK[4]. That might well be true, though it's an observational study. So even on that basis, mainstream public science communication is way ahead of (in the sense of pushing higher R0 values) what would count as MEDRS.

[1]: https://www.nytimes.com/2021/06/27/opinion/covid-vaccine-var...

[2]: https://www.medrxiv.org/content/10.1101/2021.07.07.21260122v...

[3]: https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-i...

[4]: https://www.medrxiv.org/content/10.1101/2020.12.24.20248822v...

[WP:MEDRS]: https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable...

1 comments
I believe you understand that R0 is not only a function of biology but of human behavior, density, and ventilation. If biology becomes twice as effective and all else stays the same, R0 doubles. The paper you cite [4] is about the British variant, alpha; it was estimated in that paper that alpha was 43 to 90% more contagious than the original strain. Delta is way stronger than alpha, which is why it is now the dominant strain in the UK. I don’t care much about R0 as a global or country average, but delta being 2 to 3 times worse than the original is no surprise, but rather common sense based on the rate it outpaces other weaker variants.
You're correct that paper is about alpha, not delta. Apparently the CDC official pages haven't been updated with delta, but when they are (based on leaked internal presentations) it's likely it will have the much higher R0 estimate as you say.

I personally remain skeptical that an R0 of 8 will hold up once biological evidence is taken into account. Reasonable people can disagree.

But then it doesn't make sense to talk about R0 of a specific delta variant at all because that R0 for delta will be different for different seasons, different countries, even different cities etc.

Instead you could say current R0 in London is 8 (or whatever) and it is mostly delta variant.