Gaps are widening between rich and developing nations over the pace of coronavirus vaccine rollouts.
Among Group of Seven members, more than 50 percent of the population have been fully vaccinated.
Germany and France have started administering a third dose to keep the vaccines' efficacy. Japan and the United States plan to follow suit.
But the World Health Organization says only around 3 percent of people in the African continent are fully vaccinated.
Dr Siddhartha Datta, who is in charge of vaccinations at the WHO Europe office, told NHK that the pandemic will persist unless countries protect not only their own people but also those in neighboring countries.
Some developing nations have been slow in establishing vaccination frameworks.
In May, the southern African country of Malawi discarded about 20,000 doses donated from the international community because they were not used by their expiration date.