1. There are plenty of opportunities to volunteer, especially in big cities
2.In Curitiba, Hospitals like little prince, holy house and among others
Doing volunteer work, as well as helping many hospital patients, allows you to meet people who are experiencing a different situation from you.
3.Have opportunities but the most common are 18 years or older.
4.Yes, besides just signing up, visit NGOs, hospitals, nursing homes, among others.
5.Yes, it is amazing to put a smile on a person's face, make the next one happy.
The benefits are:
Opportunity to learn from others.
Bring well-being.
Practice empathy and improve sensitivity.

Vaccines are a dead or neutralized virus and bacteria that are introduced into a person`s body to prevent or immunize a person or animal from a certain disease.
With the evolution of medicine and scientific research, in a few years (probably 50 years) there will already be vaccines for incurable diseases, and countries that are now considered developing or undeveloped countries will become safer and with fewer diseases, perhaps not even. There will be more diseases in a few centuries.