1.Those who cannot tolerate multiple blood draws due to thin blood vessels.2.Those who have difficulty collecting blood and have strong pain.3.Those with a history of vasovagal reflex.4.Those who have already been vaccinated with COVID-19 vaccine.

1.Those who cannot tolerate multiple blood draws due to thin blood vessels.2.Those who have difficulty collecting blood and have strong pain.3.Those with a history of vasovagal reflex.4.Those who have already been vaccinated with COVID-19 vaccine.