Police are investigating threats made against Mississippi’s top public health officer over conspiracy theories related to the COVID-19 pandemic.

State Health Department spokeswoman Liz Sharlot also said Wednesday that law enforcement officers are investigating threats against the state health officer, Dr. Thomas Dobbs.

He has been imploring people for months to get vaccinated, but Mississippi still has among the lowest vaccination rates in the United States.

Dobbs wrote Tuesday on Twitter that he has received threatening phone calls from people promoting false “conspiracy theories” about his family.

Dobbs said one lie is that his son, who is also a physician, receives a World Bank-funded kickback when Dobbs urges people to get vaccinated. Dobbs wrote that he gets “zero” money for promoting vaccination.