The scattered stories from across the nation can play like a merciless irony: Someone checks optimistic for the coronavirus despite the fact that they’ve already obtained one or each doses of a Covid-19 vaccine.
It’s occurred to at the least three members of Congress not too long ago:
How can that occur?
Experts say instances like these aren’t stunning and don’t point out that there was one thing fallacious with the vaccines or how they have been administered. Here is why.
Vaccines don’t work immediately. It takes a couple of weeks for the physique to construct up immunity after receiving a dose. And the vaccines now in use within the U.S., from Pfizer-BioNTech and Moderna, each require a second shot a couple of weeks after the primary to succeed in full effectiveness.
Nor do they work retroactively. You can already be contaminated and never comprehend it while you get the vaccine — even for those who not too long ago examined adverse. That an infection can proceed to develop after you get the shot however earlier than its safety totally takes maintain, after which present up in a optimistic take a look at outcome.
The vaccines forestall sickness, however perhaps not an infection. Covid vaccines are being licensed primarily based on how effectively they maintain you from getting sick, needing hospitalization and dying. Scientists don’t know but how efficient the vaccines are at stopping the coronavirus from infecting you to start with, or at holding you from passing it on to others. (That’s why vaccinated individuals ought to maintain sporting masks and sustaining social distance.)
Even the most effective vaccines aren’t excellent. The efficacy charges for Pfizer-BioNTech and Moderna vaccines are extraordinarily excessive, however they aren’t one hundred pc. With the virus nonetheless spreading uncontrolled within the U.S., a few of the tens of millions of not too long ago vaccinated individuals have been certain to get contaminated in any case.