Question: What are Covid-19 vaccine breakthrough infections or vaccine escapes? Why is this happening now?

There are more vaccine candidates simultaneously in the pipeline for COVID-19 than ever before for an infectious disease. All of them are trying to achieve the same thing – immunity to the virus, and some might also be able to stop transmission. They do so by stimulating an immune response to an antigen, a molecule found on the virus. In the case of COVID-19, the antigen is typically the characteristic spike protein found on the surface of the virus, which it normally uses to help it invade human cells.

As coronavirus cases once again rise in the U.S., experts say breakthrough cases will also go up, but that doesn’t mean the vaccines aren’t working. A series of recent coronavirus infections among vaccinated athletes and government staffers has focused attention on an apparent rise in so-called breakthrough infections. But while cases involving fully vaccinated people have increased in recent weeks, experts say there’s little reason to worry. But as the pandemic continues to linger and more transmissible variants, such as the Delta variant, the virus will circulate widely, it’s expected that the number of breakthrough infections will rise.

Here’s what to know about breakthrough cases in the context of the Delta variant and what scientists are doing to track the vaccines’ efficacy: you can get COVID-19 even if you’re vaccinated, but it’s rare and likely to be mild.  Don’t panic. Research shows the current vaccines are holding up well against the delta variant. For instance, data from the U.K. suggests the Pfizer vaccine is 88% effective at preventing symptomatic COVID-19 from the delta variant after two doses. And an earlier study from the U.K. found it is 96% effective against hospitalization. Bottom line: Vaccination is still key. 

Getting COVID-19 when you’re vaccinated isn’t the same as getting COVID-19 when you’re unvaccinated. With the rise of the über-transmissible Delta variant, experts are saying you’re either going to get vaccinated, or going to get the coronavirus. Coronavirus infections are happening among vaccinated people. They’re going to keep happening as long as the virus is with us, and we’re nowhere close to beating it. When a virus has so thoroughly infiltrated the human population, post-vaccination infections become an arithmetic inevitability. As much as we’d like to think otherwise, being vaccinated does not mean being done with SARS-CoV-2.