Cancer vaccines exist both to prevent different types of cancer and to treat them. Developing a cancer vaccine is a difficult process, but there are many trials in progress that could provide a vaccine for more types of cancer in the future.
Vaccines are medicines that train the body’s immune system to fight disease.
There are two types of cancer vaccine. One targets the viruses that can cause cancer. This will only work if a person receives them before they have exposure to the virus.
Doctors can also use some vaccines to treat some types of cancer. These tend to help stop the cancer from coming back or from spreading.
This article will explain what a vaccine is and which vaccines doctors use to prevent or treat cancer. It will also look at which cancer vaccines we might expect to see in the future.
Some viruses can cause certain types of cancer. Vaccines to prevent cancer work by helping the body fight the virus.
Immune cells are part of the body’s defense against harmful molecules, such as viruses. Each immune cell has proteins, called immune receptors, on its surface. Viruses also have proteins on their surface. These are called antigens.
Receptors and antigens are unique to each immune cell and each virus. They fit together like a lock and key. When an immune cell finds the antigen that “fits” in its lock, it binds to it and destroys the virus.
Sometimes, the body might not have immune cells with the right receptors to fight the virus. Vaccines to prevent cancer work by training the immune cells to recognize the virus.
In the United States, the Food and Drug Administration (FDA) have approved two vaccines to prevent cancer: the human papillomavirus (HPV) vaccine and the hepatitis B vaccine.
The sections below will look at each of these in more detail.
The American Cancer Society state that HPV is very common. In the U.S., around 8 in every 10 people will come into contact with it.
Many cases affect people in their late teens or early 20s.
How can a person catch HPV?
A person can catch HPV if they come into contact with someone who already has the virus. This might be
Since HPV can cause no symptoms, a person may not realize that they have it.
What can HPV cause?
According to the
For some people, however, HPV can cause:
- cervical cancer
- vulvar cancer
- vaginal cancer
- penile cancer
- throat cancer
- oropharyngeal cancer, which affects the mouth and throat (specifically the tongue and tonsils)
Experts do not know why some people with HPV will go on to develop cancer while others will not.
Who should have the HPV vaccine?
The American Cancer Society do not recommend the HPV vaccine for anyone over the age of 26 years.
How do doctors give the vaccine?
The vaccine usually requires two doses, with the second dose arriving 6–12 months after the first.
Children who receive the first dose after the age of 15 years will need three doses over the course of 6 months.
Hepatitis B vaccine
In other people, HBV is a long-term illness that doctors call chronic HBV infection.
What can hepatitis B cause?
How can a person catch hepatitis B?
Hepatitis B spreads through bodily fluids, such as blood and semen. It can also pass to a fetus during pregnancy. People may also catch it through:
- sharing razors or toothbrushes
- having sex
- sharing needles or syringes for drug use
Who should have the hepatitis B vaccine?
Anyone under the age of 19 years who has not received the vaccine should ask their doctor for it.
Unvaccinated people in the following at-risk groups should also request a vaccine:
- people whose sexual partners have HBV
- sexually active people who are not in a monogamous relationship
- people who are undergoing testing or treatment for a sexually transmitted infection
- males who have sexual contact with males
- people who share equipment for injecting drugs
- healthcare and public safety workers who may come into contact with other people’s blood or bodily fluids
- people in corrections facilities
- survivors of sexual assault
- people who are traveling to areas with high rates of HBV
- people who are living with the following conditions:
How do doctors give the hepatitis B vaccine?
The vaccine can come in the form of two, three, or four stages of injections.
In most cases, people who have received the HBV vaccine will be immune to the virus for life.
Like viruses, cancer cells also have antigens on their surface. However, immune cells do not usually have the right receptors to bind to them.
Vaccines to treat cancer tend to work by helping the immune system find, bind to, and destroy cancer cells.
Vaccines for cancer treatment can:
- prevent cancer from returning
- kill cancer cells that have remained in the body following treatment
- prevent a tumor from growing or spreading
Doctors can use vaccines alongside other cancer treatments, such as chemotherapy.
Current cancer-treating vaccines
So far, the FDA have only approved the
- BCG live: This vaccine can treat early stage bladder cancer.
- Sipuleucel-T: This vaccine can treat prostate cancer.
- Talimogene laherparepvec: This vaccine can treat melanoma.
Vaccines to treat cancer must cater to an individual’s needs. Scientists build each medicine to target the antigens on that person’s particular cancer cells.
Immunotherapy is a relatively new field, and doctors are learning more all the time.
There are currently lots of clinical trials looking at the use of vaccines in different types of cancer.
Researchers are currently studying more possible vaccines for many types of cancer, including:
Developing cancer vaccines is difficult for a number of reasons. The list below will look at these in more detail.
- Weakened immune systems: Cancer cells are able to grow because they suppress the immune system. This means that immune cells are weaker and more difficult to train.
- Tumor size: A vaccine cannot always treat a larger or more advanced tumor on its own. Doctors may need to provide other forms of treatment alongside the vaccine.
- The appearance of the cells: Cancer develops when the body’s own cells start to multiply uncontrollably. This means that cancer cells can look just like normal cells to the body’s immune system. Therefore, it may not always attack cancer cells.
- Unpredictable responses: Older adults and people who are sick have weakened immune systems. This means that their bodies might not be able to respond to a vaccine as well as they need to.
Vaccines that prevent cancer work by training the immune system to recognize and destroy the viruses that can lead to cancer. The HPV vaccine can protect against cervical cancer, for example.
Vaccines that treat cancer work by training the immune system to recognize and destroy cancer cells. There are currently only two of this type of vaccine in use in the U.S.
Many more are in the pipeline. However, the complexities of the immune system make their development very challenging.