“People who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice,” it said.
On Friday, UN Secretary-General Antonio Guterres asked for international organizations, world leaders and the private sector to join the effort to speed up development and distribution of a vaccine.
Any vaccine should be safe, affordable and available to all, Guterres said at a virtual meeting, which was attended by the leaders of Germany and France.
Absent though were the leaders of China, where the virus first emerged late last year, and the United States, which has accused the WHO of not warning quickly enough about the original outbreak.
The spread of COVID-19 is increasing other medical risks as well with the WHO warning nearly 400,000 more people could die from malaria because of disruption to the supply of mosquito nets and medicines.
Saturday marked World Malaria Day, a disease which the WHO said could kill around 770,000 this year, or “twice as much as in 2018”.