Population growth and the future of India and Nigeria

In 2015, the UN released a report stating that the world population will grow to 9.7 billion by 2050. According to the report, nearly 1/5 of the world's human population will live in India (1.7 billion people); Africa will account for roughly 1/4 of the world population (2.5 billion people) and Nigeria will surpass the United States in population size. In 2010, the birth rate in Africa stood at 4.7 children per adult female.

The predictions above take into account population-altering variables, such as an HIV epidemic. Although South Africa has the largest HIV-stricken population in the world, the second and third-largest number of HIV victims are in Nigeria and India (est. 3.2 million and 2.1 million HIV patients). Excluding population-altering variables like HIV, estimates for India's population in 2050 range from 1.7 billion to somewhere under 3 billion.

In recent events, the U.S. company Gilead Sciences has developed Truvada, an increasingly-available medication for treating HIV. Truvada was unveiled some time ago, in 2012. Generally speaking, drug patents last twenty years which means, under the most probable circumstances, rip-offs will be produced as early as 2032. What will be the impact on the populations of Nigeria and India?