Born in Nigeria, the son of a microbiologist. He immigrated to the United States at age five with his family. In his memoir, Ladapo said he had been traumatized by sexual abuse from a babysitter. Ladapo graduated from Wake Forest University, received his medical degree from Harvard Medical School and PhD from Harvard Graduate School of Arts and Sciences. Ladapo, however, has been critical of many public health measures, including mask-wearing, lockdowns and vaccines, and his appointment comes as public health experts urge the state to take a more serious approach to the pandemic. Around early 2020, Ladapo began to write op-eds for The Wall Street Journal on the emerging COVID-19 pandemic, notwithstanding a lack of specialization in infectious diseases, and gained prominence as a skeptic of mainstream consensus on prevention and treatment. In these columns, he promoted unproven treatments, including hydroxychloroquine and ivermectin, questioned the safety of vaccines, and opposed lockdown and mask mandates deriving from his "experience in treating COVID-19 patients at University of California, Los Angeles." However, UCLA's staff scheduling roster did not have him assigned to treat any COVID-19 patients, and several of his colleagues said he had never treated any COVID-19 patients. Later that year, Ladapo signed the Great Barrington Declaration, which argued for reaching COVID-19 herd immunity by the fringe notion of "focused protection", where the less vulnerable people were allowed to be infected. On March 10, 2023, Ladapo was publicly rebuked by the CDC and FDA for disseminating vaccine misinformation in response to a letter he wrote to the agencies that had misinterpreted data from the Vaccine Adverse Event Reporting System (VAERS). In a letter to parents amid a 2024 measles outbreak at a Fort Lauderdale-area school, Lapado acknowledged the "normal" recommendation that unvaccinated children stay home, but stated his department was "deferring to parents or guardians to make decisions about school attendance.