The vaccine usually takes up to 14 days to work.
During this period, you’re still vulnerable to catching the virus.
Some people mistakenly think the vaccine has given them flu, but the vaccine does not cause flu – instead, it gives your body the instructions it needs to fight off an infection should you catch it.
There’s still a chance you might get flu after getting vaccinated, but it’s likely to be milder and not last as long.
Protection decreases over time which is why a vaccine is offered every year.
The vaccine is frequently updated to best match the strain or version of flu that experts expect will be circulating.
