Peru's foreign minister resigned Sunday, the second top official to step down amid a growing scandal over politicians receiving COVID-19 vaccinations well before the general public.

The South American nation has been badly hit by the pandemic, with its hospitals overwhelmed and a targeted vaccination program for health workers rolling out only from Feb. 8.

Public resentment over officials receiving vaccinations – despite there being no date for a wider immunization drive – has seen at least two government officials resign.

Peruvian media said that Attorney Gen. Zoraida Avalos had opened a "preliminary investigation" against ex-president Martin Vizcarra and others responsible for the early vaccination of senior officials.

Top diplomat Elizabeth Astete tweeted Sunday that she had received the jab last month, calling it a "serious mistake" and saying she would not get a second dose. Health minister Pilar Mazzetti also stepped down last week following a newspaper report that former president Vizcarra had received a shot of the Chinese Sinopharm vaccine in October.

Peru only began its immunization drive, starting with health workers, in early February after receiving 300,000 doses of the vaccine.

There is still no date for a general vaccine rollout, but the government has said it intends to inoculate 10 million people by July. Vizcarra, 57, received the jab just weeks before being impeached and removed from office on charges he was "morally incompetent."

The ex-president – who is now campaigning for a seat in Congress – admitted last week he and his wife had taken part in a vaccine trial, adding he had kept quiet about it as "volunteers have to maintain confidentiality."

Lima's Cayetano Heredia University, which is leading clinical tests of the Sinopharm vaccine, on Sunday denied Vizcarra had been a trial volunteer. Vizcarra expressed "great surprise" at the university's statement, reiterating he had received two doses as a trial subject. He insisted there had been no "administrative fault or crime," and warned his actions were being exploited by "enemies of the country."

The scandal has sparked outrage in the South American nation of 33 million, currently facing a second wave of the virus that has seen cases quadruple. "It is not possible that in the midst of a crisis public office is used for personal gain. Investigation and punishment of those responsible is urgently needed," President of the Peruvian Congress Mirtha Vasquez told America TV. Peruvian media has speculated there may be numerous officials who are already vaccinated, prompting Sagasti's chief of staff and 12 other ministers to state they have yet to be immunized.

The 76-year-old president was publicly vaccinated last Tuesday alongside health personnel. Peru has recorded more than 1.2 million coronavirus cases and over 43,700 deaths.