While the FDA has authorized both Pfizer and Moderna’s COVID-19 vaccines for widespread use, millions of Americans have been waiting for their opportunity to receive the vaccine.
At the beginning of the vaccine rollout phase, nursing home residents and health care workers were the first to receive their COVID-19 vaccine. Since the first phase, some essential workers, like teachers and grocery store employees, and adults over 65 have also become eligible in certain locations.
As more Americans across the nation become eligible, there are still questions about how quickly the vaccine works.
Laurel Bristow, an infectious disease clinical researcher, told People vital information people should know before receiving their vaccine.
How does each vaccine work?
Bristow says that the Moderna and Pfizer vaccines are able to teach the body’s cells how to make a spike protein that will create an immune response to fight off COVID-19. Both vaccines require two doses.
Pfizer: Second dose is given three weeks after the first.
Moderna: Second dose is given four weeks after the first.
“Your first dose trains your immune system to respond to the spike protein,” Bristow said. “And then the second dose is the booster to make sure that it can mount a really strong immune response, if the virus is introduced to the body.”
How much protection does each dose provide?
After one dose of either Pfizer or Moderna's vaccine, a person has around 50% immunity to the virus. However, the second dose brings it up to about 95%.
Is each dose immediately effective?
Not so fast. Bristow says the body needs to process the vaccine in order to build up the body's immune response.
How long does it take for the COVID-19 vaccine to give you immunity?
"Your immune system starts to kick in, but to really get to the peak efficacy that we all know as 95 percent, it's going to take two weeks after your second dose," Bristow added.
Bristow elaborated that people who receive the Pfizer vaccine can expect to reach 95% immunity 5 weeks after their first injection, while those who receive Moderna will get to 95% immunity six weeks after their initial dose.
Can you still get COVID-19 after a first or second dose of the vaccine?
The answer is yes because the protection doesn’t happen right away.
"It's going to take two doses in time to get to the 95 percent efficacy,” Bristow said. “And especially after the first dose, it's not going to happen immediately that you are then protected from symptomatic COVID."