Alberto Fernández, the Argentine politician and lawyer who became president of the country in 2020 has tested positive for COVID-19 after being fully vaccinated, CNN reports. 

President Fernández vowed to be inoculated with the vaccine first, hoping to set an example for the rest of his country.

However, nearly two months after receiving the Russian-made Sputnik V, Fernández tested positive for COVID-19.

In a series of tweets posted Friday (April 2) evening, which happens to be the 62-year-old leader's birthday, Fernández said he experienced a fever and slight headache, which led to his decision to be tested.

According to CNN, an antigen test followed by a PCR test confirmed his COVID-19 diagnosis this weekend, according to Fernández's medical team; the Argentinian President's health remains "stable, asymptomatic, with parameters within normal ranges."

Medical experts say it is possible to become infected and test positive for COVID-19 after being vaccinated. While vaccination reduces the likelihood of disease, scientists have yet to determine to what degree each coronavirus vaccine prevents all infections.

"I'm already isolated, complying with the current protocol and following the instructions of my personal doctor," President Fernández confirmed. "I have contacted the people I met in the last 48 hours to assess whether they constitute close contact."

Argentina became the first Latin American nation to begin administering the Sputnik V vaccine to its population in late December with a purchase of up to 25 million doses. 

Fernández received his first dose of the vaccine on January 21, and his second in February, a press officer at the Presidential Casa Rosada confirmed.

As of Sunday, Argentina had over 2,383,000 confirmed cases of COVID-19, and 56,106 deaths due to the virus.

President Fernández urged citizens to remain vigilant in taking measures to ward off the virus.

He took to Twitter to express himself, saying, "It is clear that the pandemic did not pass and we must continue to take care of ourselves."