MILAN (Reuters) - The best measure of success for the new U.S. government of President Joe Biden will be the speed at which it rolls out COVID-19 vaccines, BlackRock Chief Executive Larry Fink said on Thursday. Speaking at online event organized by a business forum linked to Italy’s G20 presidency, Fink said he was confident the new administration would focus on sustainability in the first 90 days and smother any tensions with other countries. It’s about ... have America stand again for the principles of democracy ... and multilateralism ... and at the same time be aggressive and forthright in terms of the rollout of the vaccination,” the head of the world’s biggest asset manager said. Fink said it was a priority to rebalance the economy given the uneven impact of the pandemic across different sectors, but that could not happen until the population reached herd immunity and industries built on “aggregation” could be revived. “The economy will accelerate ... (once) we feel safe and secure again,” he said.