In between their first and second doses of the Pfizer/BioNTech vaccine, rates of infected plummeted. The team looked at the rate of infections during the three weeks or so before the workers got a second dose of vaccine. Clinical trials show a big boost in antibody production after the second dose of either the Moderna or Pfizer vaccine. For many vaccines, such as hepatitis B vaccine, multiple doses are needed to produce long-lasting immune protection. "For some COVID-19 vaccines, an important reason for multiple doses is to increase the strength of antibody response."

Source: The Nation February 19, 2021 12:56 UTC