This article was originally published at https://www.vox.com on August 21, 2021. Written by Dylan Scott.
The Covid-19 pandemic has changed, and with it, so has the effectiveness of the vaccines.
The bottom line remains the same: The mRNA vaccines from Pfizer and Moderna that are most prevalent in the US are still quite effective in preventing any illness from the novel coronavirus, and extremely effective in preventing the kind of severe illness that leads to hospitalization and death. On Wednesday, the Centers for Disease Control and Prevention confirmed those basic facts with its most robust data yet.
But the statistics that were widely publicized when those vaccines were first approved in December — the ones that showed vaccines were 95 percent effective in preventing all illness and 100 percent effective in stopping hospitalization or death — are now thoroughly out of date. The risk that a vaccinated person would experience symptoms if they contract Covid-19 is higher than it was back then, even if it is still significantly lower than if the person were unvaccinated. The now-dominant delta variant is likely to blame.
So exactly how effective are the vaccines against this new, more dangerous iteration of the virus? And how long does immunity provided by the vaccines actually last?
