Why Vaccinated People Still Need to Wear a Mask

Now that the world has successfully completed history’s fastest development of a new vaccine, you might be wondering why we don’t always just make one this fast. If the Pfizer and Moderna vaccines are safe and effective and the process to produce them didn’t cut any corners … well, why does it normally take around a decade to do something we just did in less than a year?

The answer to that question is inextricably tied up with another question floating around: Once you get the vaccine, can you just go back to your normal life full of hugging people and not wearing a mask?

If only we knew for sure. And we don’t know because there are some things that got skipped over when scientists went and made a vaccine faster than anyone thought possible. Nice-to-know details were pushed to the back burner in a rush to make sure the new vaccines would be safe and effective. And one of those details is whether the vaccines keep people from spreading COVID-19 or whether they just keep those who do contract it from getting sick.  Theoretically, a vaccine should stop both the infection as well as the transmission and spread,” said Dr. Purvi Parikh, an immunologist with the nonprofit Allergy & Asthma Network and a co-investigator on the Pfizer vaccine trials.

But we don’t know yet if that is true of the COVID-19 vaccines, she told me. That’s because the focus of the clinical trials was narrow. It had to be because of the time constraints. Scientists wanted to know whether these things prevented illness. They wanted to know whether the drugs were safe. And they got those answers.

But getting those questions answered fast came at the expense of answering other questions — like whether vaccinated people can still spread the virus. “With a lot of other vaccines, you have years of data to analyze that,” Parikh said.

So, experts are being careful — balancing their excitement and relief with caution that you can’t just switch off 2020 Mode and return to a normal state of being. They need a little more time to know for sure.

If someone was protected from symptoms of COVID-19 but still capable of spreading it, it wouldn’t be that shocking. There’s a hypothetical mechanism that could allow this to happen biologically, said Deepta Bhattacharya, a professor of immunobiology at the University of Arizona. And that mechanism is … well … it’s boogers and phlegm.