The specific part you excerpted, by itself, is confusing. When I read just your comment, having not read the article, I interpreted it as: "it takes eight time

The specific part you excerpted, by itself, is confusing. When I read just your comment, having not read the article, I interpreted it as: "it takes eight times as many antibodies from a vaccinated individual to block the virus [compared to an unvaccinated individual]" When I went to find the excerpt within the article, I realized in context it meant: "it takes eight times as many antibodies from a vaccinated individual to block the [delta variant] virus [compared to blocking the alpha virus]" And separately offers the information that for antibodies from natural immunity, the difficulty jump from alpha to delta is 5.7x instead of 8x. Which would suggest that having natural immunity could be better than having only vaccine immunity, but definitely doesn't suggest that being unvaccinated is better than being vaccinated. So there's no mystery for vaccinated individuals having better odds against COVID than unvaccinated ones.