New variants and the vaccine.
At the beginning of the pandemic the covid-19 variant had not mutated and started spreading at such a rapid rate. Fast forward to a year since the pandemic started and new variants of the virus are popping up everyday and the spread of the virus increasing.
With the race to vaccinate people all around the world, majority have not yet been vaccinated especially in third world countries.
At this point in time the world is not as vulnerable to the virus as at the beginning of the pandemic when there were no vaccines but there is still some risk of new variants coming up that are resistant to the vaccines.
The new variants can undermine the efforts to vaccinate people on a mass level however the continued efforts to vaccinate a lot of people to mitigate the spread of the virus is going on well.