What is a booster dose?
Booster doses are administered to a vaccinated population that has completed a primary vaccination series. when, with time, the immunity and clinical protection has fallen below a rate deemed sufficient in that population. The objective of a booster dose is to restore vaccine effectiveness from that deemed no longer sufficient.
The reason of giving booster doses
The current primary goal of immunization during COVID-19 pandemic remains the same, to offer protection against hospitalization, severe disease and death.
Hence, booster doses may only be needed if there is an evidence of insufficient protection against these disease outcomes over time.