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So in the past week, we've learned that asymptomatic patients may take longer (2 months) to develop fewer antibodies, which then wane just as quickly. Along with concerning implications for vaccine platforms, dosing schedules & herd immunity...(1/n)
This further undermines serosurveys and means it's probably already too late to validate a new retrospective analysis of ILI data that suggests COVID-19 was more widely prevalent in early March...(2/n) https://stm.sciencemag.org/content/early/2020/06/22/scitranslmed.abc1126
If those timelines prove correct, then we should expect to see reinfections about recovered individuals relatively soon - but may have a hard time identifying them as such given the limitations of PCR tests, too. (3/n)
Until then, though, we won't know whether T cells provide sufficient protection or, conversely, whether immune enhancement could lead to more severe subsequent infections. Either has massive implications for vaccine development, which has focused mostly on antibodies. (4/n)
Moreover, existing vaccine candidates already seemed more likely to reduce illness severity than to prevent initial infection. Yet even relatively mild cases can have long-term consequences ("post-Covid syndrome") - including triggering diabetes. (5/n) https://www.nature.com/articles/d41586-020-01891-8
Meanwhile, it appears that infection may also complicate pregnancies more than initially expected. (6/n) https://www.nytimes.com/2020/06/24/health/coronavirus-pregnancy.html
The recent surge in US cases may indeed be driven by 20- to 44-year-olds, who are (relatively) less likely to require hospitalization. But in other countries, this is precisely the age group whose behavior at bars & restaurants seeded wider clusters of infection. (7/n)
So no, it absolutely does not "bode well" that cases are skewing younger. It is *not* likely to result in herd immunity or otherwise "protect" the elderly. And many of these patients are *also* vulnerable, whether they realize it or not. (8/8)
