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How much protection does each dose provide?
After one dose of either Pfizer or Moderna s vaccine, a person has around 50 percent immunity to COVID-19, and the second dose brings it up to about 95 percent.
Is each dose immediately effective?
Not quite the body needs time to build up its response. 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 says. That means that people who get the Pfizer vaccine can expect to be at 95 percent immunity five weeks after their first injection, and those with Moderna will reach that point six weeks later.