Vaccine FAQs: Why precautions are still needed after you get your shot

Time & Date

Thursday, February 18, 2021

With the COVID-19 vaccine now beginning to circulate throughout the community, questions remain regarding best safety precautions and practices for vaccinated individuals.

While the Pfizer vaccine is 95% effective for preventing illness, the possibility of transmission is still not fully understood.

“The vaccine’s efficacy is very high, so if you received the vaccine, you’re in pretty good shape,” said Anthony Hartzler, MD, associate professor and infectious disease specialist with UT Health Physicians. “But the million-dollar question is whether these vaccines prevent you from transmitting COVID-19 to others, and that question is unanswered at this point. It’s quite possible that you can be infected and transmit the virus without getting sick even after you’ve had one of these vaccines.”

Until more is known, Dr. Hartzler and other experts advise vaccinated individuals to continue the same measures they did before getting vaccinated, such as wearing masks, avoiding crowds and maintaining social distance.

“Every social interaction is two-way,” he said. “So just because you yourself are protected doesn’t mean that other people around you are protected.”

These precautions must continue until the vaccine is widespread in the community or until studies can prove that vaccination also prevents transmission of the virus, he said.

Another important factor for vaccinated individuals to understand is how long the vaccine takes to reach its highest efficacy, Dr. Hartzler said. The Pfizer vaccine is most effective after one week from the second injection, or four weeks from the first injection, so remaining vigilant with safety practices is crucial to avoid potential infection and illness, he said.

Other frequently asked questions:

Q: Is it safe to gather for shared meals and socialize freely with members of different households if we know we’ve all been vaccinated?

A: This is a difficult question and hard to answer until we know more about how the vaccines work. If you have been vaccinated then it’s unlikely that you could get sick at a gathering like this. But you still might be able to catch the virus and then later spread it to someone else, even though you do not get sick or have symptoms.

Q: Can my unvaccinated children hug their vaccinated grandparents now?

A: The vaccinated grandparents would be largely protected. But it might be possible for them to pick up the virus and pass it to their grandchildren or someone else, even though the vaccine keeps them from getting sick.

Q: When can we stop wearing masks?

A: Because we don’t know if the vaccines stop people from spreading the virus, we need to keep wearing masks until most people have been vaccinated and the spread of COVID-19 is low in the community.