【明報專訊】LEADERS of the Group of 20 nations have held a summit via a video conference to discuss the pandemic and promised to take all necessary public health measures to curb it. Viruses are not restricted by borders, and no one can be insulated from their harm. Though the US is equipped with the most advanced medical technology and its president Donald Trump once claimed that the US would "never" rely on support from foreign countries, recently he has been soliciting help and sourcing medical supplies behind closed doors. This goes to show that no country can tackle this once-in-a-century pandemic on its own.