russians are still hesitant to get the sputnik vaccine. translator: we re afraid of getting sick. that we did not get vaccinated because we re also afraid of that. reporter: a w.h.o. said moscow is one of several places where the delta variant is thriving. with so many people across the world still unvaccinated, there s plenty of opportunity for it to circulate even more. the delta variant is well on the way to becoming the dominant variant globally because of its significantly increased transmissionability. reporter: one w.h.o. official said africa is particularly vulnerable because of a lack of vaccines. delta variant has been detected in at least 14 countries on the continent. even countries that have had success with their vaccination programs have been inundated with new cases. more than 46% of the population in the uk is fully vaccinated but covid-19 infections are