9 dangerous diseases that could be prevented by vaccines within the next decade, from HIV to cancer

REUTERS/Karoly Arvai

One of the best defenses we have against viral infections is the vaccine. 

Vaccines prepare the body's immune system to fight an incoming infection; they've been credited with the widespread eradication of smallpox and the near-eradication of polio. 

But for all the conditions vaccines have succeeded in eradicating, there are still many diseases for which no vaccine exists.

Researchers are finding ways to use the immune-system-triggering effects of vaccines to tackle unexpected diseases, such as cancer and drug addiction.

To get approved, vaccines need to show that they're both safe and effective at preventing diseases or — if they're used therapeutically — at activating the immune system to go after existing diseases. That process can take years or even decades.

Here are nine vaccines currently in development that could dramatically change how humans live.

Gonorrhea

Gonorrhea, a sexually transmitted bacterial infection, is typically treated with antibiotics. But in the past few years, it's become untreatable in some cases. 

In addition to new antibiotics that can combat the infection, the World Health Organization is calling for a vaccine. There is at least one in development. 

But in a surprising turn of events, researchers looking at data on a meningitis outbreak and subsequent vaccination effort in New Zealand found that the vaccine protected against gonorrhea as well. As it turns out, the bacteria that cause meningitis and gonorrhea are very closely related — like "cousins."

The vaccine used to target that specific meningitis outbreak was administered from 2004 to 2006, and is no longer in use. It remains to be seen whether someone will develop it as a vaccine for gonorrhea alone. 

Cancer

There are already some vaccines that prevent certain types of cancer. The vaccine against human papillomavirus (HPV), for example, can prevent six different kinds of cancer. Another vaccine for hepatitis B prevents liver cancer as well. 

There's also a push to use vaccines once a person has been diagnosed with cancer. One such treatment was approved for prostate cancer in 2010. The treatment reprograms the body's immune system to go after a particular protein that helps the immune cells attack the cancer cells.

Other vaccines on the horizon could take a more personalized approach, pinpointing cancer mutations and amplifying the body's immune system to fight off certain types of cancer cells. 

Malaria

Malaria is a parasitic infection spread by mosquitoes that can lead to chills, fever, and nausea, along with other severe complications including organ failure. The disease is responsible for more than half of mosquito-related deaths, predominantly in sub-Saharan Africa. 

There is no widely available vaccine for malaria, though three countries are set to take part in a pilot program for a malaria vaccine starting in 2018, the World Health Organization said in a news release.

The number of deaths caused by the disease are already dropping, however, due to prevention efforts like insecticides that are sprayed and used in netting. Between 2000 and 2015, malaria deaths fell 62%, translating to 6.8 million lives saved, according to the WHO.