Covid-19 or Coronavirus disease-2019 is a major global public health crisis. Knowledge about the disease continues to evolve from the day since it first came to light in December last year. While, this has helped to better manage patients, we are still nowhere close to the end of the pandemic. The numbers keep on rising every day. Globally, there are now more than 12 million cases and more than 500,000 deaths.
Since, Covid-19 is a new disease caused by a new virus, there is no natural immunity against the virus. And, it is still not known whether the infection provides immunity to the affected person and for how long.
Till herd immunity crosses 70%, the disease will continue to spread. But, allowing development of this level of herd immunity naturally may take many years; moreover, this would add to the already high disease burden as well as mortality. A vaccine would expedite development of herd immunity.