World leaders on Friday pledged to work on vaccines and tools to fight against Covid-19. The event was attended by French President Emmanuel Macron and other leaders. WHO Director-General Tedros Adhanom Ghebreyesus was part of the event. WHO called it a 'landmark collaboration'. UN chief Antonio Guterres, Spanish Prime Minister Pedro Sanchez were among the attendees. The US, however, was missing from the virtual event. Show of unity for UN and WHO comes after Trump criticized WHO's response to Covid-19. Trump administration had earlier vowed to cut US funding to WHO.