Past and present world leaders have urged that any eventual COVID-19 vaccines and treatments should be made available to everyone free of charge. South African President Cyril Ramaphosa and Pakistani Prime Minister Imran Khan were among more than 140 signatories of a letter saying vaccine should not be patented while the science should be shared among nations. The World Health Assembly (WHA), the policy-setting body of the World Health Organization, holds its annual general meeting next week. The signatories called on the WHA to rally behind the cause. "Governments and international partners must unite around a global guarantee which ensures that, when a safe and effective vaccine is developed, it is produced rapidly at scale and made available for all people, in all countries, free of charge," the letter said.