SAO PAULO (AP) — Small groups of protesters gathered in Brazil's two biggest cities Sunday to demonstrate against any mandate for the taking of a coronavirus vaccine, supporting a rejection campaign encouraged by President Jair Bolsonaro.

People assembled in downtown Sao Paulo calling for the removal of Sao Paulo state Gov. Joao Doria, who has said state residents will be required to take a vaccine, likely the one being developed by Chinese biopharmaceutical company Sinovac and the local Butantan Institute.

“Doria will fall!” the protestors chanted. “Out with Doria!”

The CoronaVac, as it is being called, has been a prime target for skepticism from Bolsonaro and others, with the president saying Brazilians will not be guinea pigs to the Chinese. The issue has become a talking point in mayoral and city council campaigns for elections later this month, and as most health professions support vaccination, social media campaigns have raised questions about possible perils of vaccines.

Demonstrators supporting Bolsonaro on the question also protested on Copacabana Beach in Rio de Janeiro.

A PoderData poll said this week the percentage of Brazilians who say they would take a coronavirus vaccine dropped to 63% in October from 85% four months earlier. The percentage rejecting the idea of taking a vaccine rose to 22% from 8% in July.

The Getulio Vargas Foundation think tank said an analysis of 2 million Twitter postings found that 24% of profiles identified as pro-Bolsonaro and they accounted for 56% of mentions against the vaccine. On the other side, 47% of profiles identified as pro-vaccine and represented 32% of the postings.

In October, Doria said vaccination would be mandatory in his state, and Bolsonaro’s health minister, Eduardo Pazuello, announced that the country had agreed to purchase CoronaVac doses produced locally.

The president quickly responded that he would not allow the import of vaccines from China. Though the health regulator later gave permission for Butantan to import 6 million doses, on Thursday the president said on his weekly live program that he would not buy the vaccine and that the governor should “find someone else to buy your vaccine.”

On Friday, Vice President Hamilton Mourao told the magazine Veja that “of course” the country will buy the Butantan-Sinovac vaccine. Bolsonaro immediately responded that he is the one with the power and he won’t spend on any vaccine that is not approved by the Brazilian health regulator.

Brazil has reported more than 5.5 million confirmed cases of coronavirus infections, and about 160,000 people have died from COVID-19, the disease that can be caused by the virus. While the spread of the virus has begun slowing, public health experts warn people not to let their guard down.

Health professionals are also speaking out in an effort to shore up support for vaccines.

“Vaccination en masse with high coverage would be the only mechanism we have to control the epidemic, at least in the medium-term,” Jesem Orellana, an epidemiology researcher at the Oswaldo Cruz Foundation, a scientific research institution, said in a written response to questions. “We have failed over the past eight months with non-pharmacological measures.”

Dr. Paulo A Lotufo, a University of Sao Paulo epidemiologist, said national immunization programs have been well-received by the Brazilian public, which has seen the positive impact of vaccinations, including against meningitis and polio.

“The population will take the vaccine,” Lotufo predicted in a Skype interview. “More than 90% of the population will vaccinate.”