As with so many infectious diseases, lack of determination is the real stumbling block. The United States and other donor nations could argue that we already do more than our share, contributing billions annually to the fight against TB and other infectious diseases. But donors still fall short by more than half on the funding the W.H.O. says it needs to end the TB epidemic by 2030. Until we get the job done, we need to have a broader sense of what “our share” could yet entail: Up to 13 million Americans currently live with latent TB infection, according to estimates from the Centers for Disease Control and Prevention. The realities of modern travel mean that none of us is protected from a TB resurgence until we have protected people everywhere.

It’s the same story with malaria, which used to sicken and kill Americans as far north as the Great Lakes until a well-funded federal initiative protected us. Consciously or otherwise, we then set malaria aside as a “Third World” disease. In June, however, for the first time in two decades, homegrown malaria cases turned up in Texas and Florida, raising the specter that it might again become endemic in the United States.

That ought to serve as a reminder that an estimated 247 million cases of malaria occurred worldwide in 2021, and 619,000 people died. The vast majority of them were children under the age of 5 in sub-Saharan Africa and South Asia. Malaria prevention has stumbled at times because of rapidly evolving resistance to drugs and insecticides. But we are now making major progress with a variety of new tools and a more coordinated and agile response.

Sixteen nations, from El Salvador to China, with efforts coordinated by the World Health Organization, have eliminated malaria since 2000, with another 10 countries aiming to stamp it out in the next two years. Moreover, public health agencies for the first time now have a vaccine against malaria, and about 1.7 million young children across three countries in Africa — Ghana, Kenya and Malawi — have already received at least one dose since the start of a pilot program in 2019. The vaccine is only moderately effective, but by preventing about 40 percent of cases of Plasmodium falciparum, the deadliest malaria variety, it’s expected to save tens of thousands of children every year. With proper funding to develop other necessary tools and get them into the field, the W.H.O. goal for this decade is to drive the annual malaria death toll down to well under 100,000 — en route to eradication.

Polio, finally, offers the most immediate opportunity for a major success over infectious disease. In 1988, when international agencies, national governments and nonprofits launched an eradication campaign, polio was still endemic in 125 countries and every year paralyzed an estimated 350,000 people, mostly young children. This year, there have been just seven cases of wild poliovirus, all in one small, mountainous area on the border between Pakistan and Afghanistan, the last two countries where the virus remains endemic. Both countries are now cooperating to stop it. They have eliminated wild poliovirus from major cities and Taliban-dominated regions where it was still circulating just a few years ago. Border crossings between the two countries now require polio vaccination. And vaccination teams, often with women taking the lead, routinely travel to remote and sometimes dangerous border villages to finish the job.