Not long after announcing a $100 million donation to find a cure for Alzheimer's disease, Bill and Melinda Gates have agreed to pay off Japan's $76 million loan to Nigeria to stamp out polio, Quartz reports.

Polio has been eradicated in most countries around the world, but it's still present in Nigeria, as well as in Afghanistan and Pakistan. In 2008, according to The Conversation, Nigeria accounted for 86 percent of all polio cases in Africa. This high number was thanks in part to low immunization rates and calls from extremists to boycott polio vaccinations out of fear that they were tainted with anti-fertility steroids.

National and international campaigns were launched to lower polio rates in Nigeria, and in 2014 the nation received the loan from Japan to boost disease-fighting efforts. Progress has been made since then, with no new cases of polio reported in Nigeria in 2017. Two children had contracted polio in 2016, two years after Nigeria's last known case.

Nigeria's loan repayments to Japan were slated to begin in 2018. The Bill & Melinda Gates Foundation agreed to cover the costs after Nigeria met its goal of "achieving more than 80 percent vaccination coverage in at least one round each year in very high risk areas across 80 percent of the country's local government areas," Quartz reports. The loan will be repaid over the next 20 years.

While the Gates Foundation is lending a hand to Nigeria, the Associated Press reports that health officials in Pakistan's eastern Punjab province recently launched a new chapter in the nation's ongoing struggle against the disease. Health workers will engage in a week-long, door-to-door vaccination campaign, though efforts like this are risky due to threats from the Taliban and other militant groups, who view vaccinations as a Western conspiracy and believe they sterilize children. Anti-polio efforts in Pakistan also suffered after the CIA used vaccinations as a cover to get DNA samples from the Bin Laden compound.

[h/t Quartz]