The world finally has a malaria vaccine. Now it must invest in it | Ngozi Okonjo-Iweala

As an economist I know it makes financial as well as ethical sense to get this world-first vaccine to the millions who need it

I vividly remember the day I learned a harsh lesson in the tragic burden of malaria that too many of us from the African continent have endured. I was 15, living amid the chaos of Nigeria's Biafran war, when my three-year-old sister fell sick. Her body burning with fever, I tied her on my back and carried her to a medical clinic, a six-mile trek from my home.

We arrived at the clinic to find a huge crowd trying to break through locked doors. I knew my sister's condition could not wait. I dropped to the ground and crawled between legs, my sister propped listlessly on my back, until I reached an open window and climbed through. By the time I was inside, my sister was barely moving. The doctor worked rapidly, injecting antimalarial drugs and infusing her with fluids to rehydrate her body. In a few hours, she started to revive. If we had waited any longer, my sister might not have survived.