How Easily Can Vaccinated People Spread COVID?

How Easily Can Vaccinated People Spread COVID? Vaccination is the best protection against infection. But when breakthroughs do occur, a very basic question still has an unsatisfying answer. Yasmin Tayag The Atlantic

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Breakthrough infections are still happening, and they can lead to transmission. But we still don’t know just how widely that spread actually happens.

Vaccinated people spread the virus less overall because they are significantly less likely to get infected in the first place. In early September, the CDC found that six unvaccinated people were testing COVID-positive for every one vaccinated person. But there are plenty of reasons to be optimistic beyond that. Some recent research shows that even once they’ve been infected, the vaccinated are less likely to spread the coronavirus than the unvaccinated. “We’re back in this category of Yeah, it can happen, but it seems to be a very rare event,” Ross Kedl, an immunology professor at the University of Colorado School of Medicine, told me.  ...

...researchers in the United Kingdom found that the Pfizer and AstraZeneca vaccines consistently reduced transmission downstream of breakthrough cases. Much of the original Delta concern was based on something called “viral load”—the amount of virus a person carries while infected. But the researchers concluded that viral load is just one of many factors correlated to transmission reduction. In other words, even if vaccinated and unvaccinated people have the same viral load, it may not necessarily mean they are just as likely to spread the virus. ...