One of the questions people have about the vaccine is how long it will take for the vaccine to give someone immunity to the virus.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the US, said complete immunity to the virus develops a week to 10 days after people receive the second dose of the two vaccines.
"The two vaccines, Moderna and Pfizer, are what is called a 'main stimulus,' an injection followed in (three to four) weeks by another injection," Fauci told CNN.
People begin to develop immunity after the first dose of the vaccine, but it is not optimal or absolute.
"After the second dose, you get full immunity sometime 7-10 days later."
Vaccines seem to offer at least as strong protection, if not stronger than the immunity that humans have, after passing Covid-19.
"If you look at the vaccine, the level and quality of the neutralizing antibodies was comparable and even better than what you see in the recovery plasma of people who have been infected and have developed an immune response."