I've worked with Water Wells for Africa (WWFA) in the past - they don't quite hit on the things you're looking for but they have partnered with an organization in Malawi called Project Heart 2 Heart. That one is run by a Malawian nurse whom I've met - they go into rural villages and host medical clinics. They are currently working to help with the relief efforts from the devastating flooding in Malawi. Project Heart 2 Heart definitely treats Malaria and would probably love to expand into immunizations if they had the funding. I don't know if they are as established as you're looking for, but I thought I would at least mention it! The nurse I have worked with, Isaac, speaks really good English so you could message them on Facebook with any questions that you have.
I, personally, like supporting WWFA because it is local people doing the majority of the work (and getting paid for it). They are run out of Manhattan Beach, CA but employ a couple people in Malawi and use a Malawian drilling company for each of their wells. They're not only bringing clean water and 100% reduction in cholera to villages, they're also stimulating the Malawian economy by not just bringing in American resources. They don't pay for education, but more girls are able to go to school in villages with wells because they don't have to spend as much time collecting water. Through connections I made during my 3 trips to Malawi, I've helped pay for one man's college degree and I'm currently helping pay for a young girl's college degree. All this to say, sometimes supporting the "little guys" helps you see where your money is going on a more personal level.
(Stepping off my soap box now - sorry about that)
Because Project Heart 2 Heart is a Malawian organization I'm not totally sure if donations are tax deductible, but I *think* you can donate to WWFA for the deduction and they will get it to Project Heart 2 Heart. If you're interested enough to ask questions, you could reach out to Kurt Dahlin with WWFA and tell him Shelby sent you. He'll probably invite you to the yearly trip he takes to Malawi.
https://waterwellsforafrica.org/https://www.facebook.com/projectheart2heart/ (they post pictures from almost all of their clinics and a yearly update).
https://greatnonprofits.org/org/water-wells-for-africa