covid reinfection
Covid-19 reinfection: What you need to know
01:38 - Source: CNN
CNN  — 

Shipments of the Covid-19 vaccine are arriving, with frontline health care workers getting immunized – some for the cameras – across the United States Monday.

While these developments mark a historic moment and hold much promise, that doesn’t mean Americans can stop wearing masks anytime soon. CNN Medical Analyst Dr. Leana Wen, an emergency physician and visiting professor at George Washington University Milken Institute School of Public Health, explains why.

CNN: Does the vaccine protect people from getting Covid-19? If so, how come I still have to wear a mask?

Wen: This is a good question! It’s important to be clear about what we know and what we don’t know about what the vaccine does. What we know is that the Pfizer vaccine is very effective at preventing symptomatic illness and severe disease. That means the vaccine appears to prevent people from getting sick enough that they develop symptoms, and very importantly, it prevents people from becoming so severely ill that they end up in the hospital. This is really great news.

Americans will still need to mask up even with the US vaccine rollout underway. Shown are two men talking while wearing masks in Central Park December 2 in New York.

Here’s what the studies don’t yet show. They haven’t looked at whether the vaccine prevents someone from car