“A two-front war,” she said.

It’s one reason the 33-year-old physician is participating in clinical trials for an experimental vaccine by the Chinese manufacturer Sinovac. It might be a chance to inoculate herself against a disease that terrified her. But it was also an opening to align herself with evidence and logic — rather than the doubts and medical falsehoods she saw proliferating across Brazil.

Brazil has long been recognized as one of the vaccine-friendliest countries in the world. It has universal health care, a strong public medical system, a population that has trusted vaccines and a history of carrying out massive and logistically challenging immunization campaigns. Yellow fever, measles and other pathogens have all been brought into submission.

That record, and a relentless coronavirus outbreak that has killed more than 150,000 Brazilians and infected more than 5 million, have made Brazil an inviting testing ground in the global race