The customer, who received the first dose of the COVID-19 vaccine on Monday, said a pharmacist contacted her and explained she was given the dosage for the Pfizer vaccine which is less than the Moderna vaccine.

CVS admitted to the error in a statement it provided to WCVB.

"Earlier this week at our pharmacy in Ipswich, a limited number of patients inadvertently received a 0.3 mL dose of COVID-19 vaccine instead of the correct dose of 0.5 mL," the spokesperson said.