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Covid-19 Vaccines

  1.  It was reported that the Serum Institute of India plans to crank out 100 million doses of Oxford University’s coronavirus vaccine for poor countries at a cost of $3 or less per dose? How does this compare with the vaccines announced by Pfizer and Moderna?
  2. Will the Covid19 virus mutate like the flu virus does requiring a new Covid19 vaccine every year?

I have a follow up vaccine question regarding immunity:
How is the duration of immunity determined for a vaccine? How often is a vaccine dose required? Has this been determined for the 2 leading COVID viruses?


The duration of immunity needs to be determined empirically, through longitudinal monitoring. Boosts need to be provided accordingly. This is determined by the "durability"  of the vaccine--its capacity to induce long-term immunological memory, and by the behavior of the agent you are vaccinating against. For example with flu, the virus changes seasonally requiring reboosts with slightly altered vaccines each year.