I gladly took 2 doses of the magnetic, microchipped experimental mRNA vaccines in April because the cost-benefit seemed clear. During the summer, I was exposed at least twice to people infected with Delta and did not get sick (yay!). However, long term frequent doses of mRNA vaccines is something for which safety data does not exist. I expect these hypothetical risks are very low, but I'm weighing this against a very low expected protective benefit for boosting (in my specific case; the argument for boosting in the elderly is fairly strong).
FWIW, the UK government decided on boosters for all adults as a result of this study (and others).
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02717-3/fulltext
Our system is rather different to the US - the government is paying for those boosters. Scientists have done the cost-benefit analysis and concluded it's worth it. Until these and similar trials were done, it was boosters for the over-50s only.
https://www.bbc.co.uk/news/health-59489988
I take some exceptions to concluding, based on this study, that boosters are appropriate:
1) boosting may merely delay rather than prevent infection in the long-run, unless infinite boosters is the plan. Sterilizing immunity, especially to various strains that followed
Wuhan Classic, is short-lived--so the actual risk would have to be modeled based on taking many, many boosters to totally avoid infection over a longer time-horizon
2) the paper deals with only immediate adverse effects and doesn't allow for more cryptic/longer-term downsides (
Donald Rumsfeld something something unknown unknowns, you know?)
3) the paper measures benefits in terms of immunogenicity and not in terms of actual health outcomes. If two shots are already highly protective against severe disease then having a higher antibody titre isn't going to make much of a difference to an individual
4) finally, the study was before the latest variant plot-twist which may have totally different tradeoffs (but see my further thoughts below)
Overall, that is a good-looking study, though, for the questions it directly attacks. And before any angry fist-shaking begins (this is the internet after all) see my shifting thoughts on boosters below based on new information.
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I am now at 50%/50% on the question of boosters. Why the change? First, a paper on reinfection rates from Omicron:
https://www.medrxiv.org/content/10.1101/2021.11.11.21266068v22.4x risk compared to wave 1 reinfections is significant but not crazy-high, which suggests the transmissibility advantage is mediated less by extreme immune escape and more through higher R0. Maybe I'm misunderestimating something about these findings, though, since the paper was updated in a hurry and I read it in a hurry. But anyway, there is also this thread on transmissibility as well, indicating the rapid rate of growth of Omnicron is not due to founder effect or selective testing--the growth anomaly is simply too big now to for this to be the case (plus elsewhere, sewage data is pointing to massive community spread in SA):
https://mobile.twitter.com/TWenseleers/status/1466501989500653568Omnicornpop might be @ R0 ~ 8.5, with effective R in South Africa currently between 3.5 and 4... So if there are currently ~100 cases in the US, everyone will be exposed within 2-3 months. This would mean:
1) not enough time for Omnibus-specific boosters
2) lower immune escape/higher R0 scenario may mean boosters are more efficacious than in scenarios with those factors reversed
3) there isn't much time to wait for more information; the median American will be exposed in 6-8 weeks
And I guess we'll see how well Paxlovid and Molnupiravir work (the mechanism of the latter makes me queasy about weird side-effects; Paxlovid seems to be based on better-understood interactions in HIV medications). US could peak at ~10M infections per day, so could get nasty--or maybe it was a spreadsheet error I had when playing with the numbers earlier today while at work, or maybe we shouldn't trust random Twitter threads so much.