Our immunity to disease is a biological wonder. It has preserved humankind from the ravages of countless pathogens. Scientists have gained valuable insights into its working, aided by microscopes and computers of extraordinary power.

   (See Box) Yet, as is evident in these days of the pandemic Covid-19, human immunity remains an agonising mystery. Its apparent uniformity as seen by the same sort of dedicated cells in all of us has indeed hidden its innate individuality. Like our fingerprints, it is unique to every one of us.

    Even as we are proud of its elephantine memory, we are at a loss to know when it fails us. Even as we welcome its emergence from hibernation in times of need, we are unable to know why it is not as strong as before. It works for some but not for all. To a world too eager to know why, all that the scientists could say is ‘It’s too early to say’! 

Outstanding insights into....