SAO PAULO, Aug 21 (Reuters) - Brazilian President Luiz Inacio Lula da Silva continues to lead Senator Flavio Bolsonaro ahead of the October election, although the right-wing challenger has narrowed the gap by one percentage point, a change within the error margin, a Datafolha poll showed on Friday.
In a simulated second-round runoff, Lula would receive 47% of the vote against Bolsonaro's 43%, according to Datafolha, which has an error margin of two percentage points. In July, Lula led Senator Bolsonaro, son of ex-President Jair Bolsonaro, by 48% to 43%.
• In a first-round scenario, Lula leads with 39% of the votes, followed by Bolsonaro (33%), Ronaldo Caiado (5%), Renan Santos (4%), and Romeu Zema (3%).
• If no candidate wins more than 50% of valid votes in the first round, the two frontrunners advance to a runoff, which has happened in every presidential election since 2002.
• Lula's approval rating fell to 47%, Datafolha showed, from 49% in July, while his disapproval rate rose to 50% from 48%.
• This was the first Datafolha poll released since the start of the official campaign, when candidates are legally allowed to actively seek votes.
• It was also the first Datafolha poll after Brazil's Supreme Court authorized Federal Police to investigate Lula's eldest son on suspicion of illicit business dealings involving the federal government.
• Senator Bolsonaro saw his poll numbers fall after the revelation in May that he asked a now-jailed banker to finance a film about his father.
• Datafolha surveyed 2,058 people starting on August 18.
(Reporting by Andre Romani; Editing by Chris Reese and Natalia Siniawski)
