<span style="color: #222222;">WHO Chief Scientist Dr. Soumya Swaminathan has said that the corona virus mutations are not expected to alter the vaccine efficacy. </span><br />'' <br />'' <span style="color: #222222;">Speaking at a live question and answer broadcast on WHO's Social media platforms yesterday, she said that testing for vaccines is underway, She added that while it is diffcult to predict when a vaccine will be ready or whether the samples being tested will meet WHO critiera, as per optimistic estimates a vaccine may be ready by the end of this year.</span><br />''