A New Zealand man received the COVID-19 vaccine up to 10 times in a single day, according to the New Zealand Ministry of Health.
People apparently paid the man to impersonate them and receive the vaccine on their behalf.
New Zealand Ministry of Health COVID manager Astrid Koornneef told the publication Stuff, "We are taking this matter very seriously. We are very concerned about this situation and are working with the appropriate agencies."
Koornneef advised, "If you know of someone who has had more vaccine doses than recommended they should seek clinical advice as soon as practicable."
Professor Nikki Turner of Auckland University told Stuff, "We have no evidence as to what side effects somebody would have with this amount of vaccine... This is not a safe thing to do, this is putting that person at risk."
Authorities publicly became aware of this issue in October, when police warned that people were assuming other's identities to receive COVID vaccines.
In New Zealand, vaccination is mandatory for most people working in health care, education, corrections, fire and emergency services.
New Zealand shifted away from a "zero-COVID" case approach earlier this month when the island nation reopened after more than 100 days in lockdown.