National Immunization Awareness Month: Vaccines & Cancer Prevention

August is National Immunization Awareness Month. This is a great time to check your vaccination status to make sure you and your loved ones are up to date on necessary immunizations, especially children, and to learn about the importance of vaccines. This is especially important this year with the COVID-19 pandemic.

Vaccines are important to protect yourself and others from serious diseases and illnesses. Most vaccines are administered in childhood, but certain vaccinations are needed throughout the lifespan, such as booster shots for vaccines previously received in childhood or yearly flu shots. 

Vaccines work by teaching the body to recognize potentially harmful pathogens so the immune system can respond and fight off infection in the future. Vaccines typically do so by injecting weakened, or even dead, parts of the germ or pathogen (such as a virus), called antigens. The antigens create a response in the body without causing illness.    

Cancer researchers have worked to develop vaccines for certain types of cancer. The Hepatitis B vaccine prevents Hepatitis B infection, an illness that can lead to liver disease and cancer. The HPV vaccine prevents HPV and six different cancers, a huge milestone for cancer research that illustrates the importance of clinical trials. 

HPV is a group of more than 150 viruses. HPV can cause six different cancers by developing cell abnormalities, including oral cancers, reproductive cancers, and, most frequently, cervical cancer. HPV is responsible for about 90 percent of cervical cancer cases, with two strains, 16 and 18, responsible for 70 percent. It is estimated that HPV causes 36,000 cancer cases per year in men and women. HPV vaccination would prevent 32,000 of those cancer cases from ever developing.

The first HPV vaccine called Gardasil was approved by the Food & Drug Administration (FDA) in 2006. It protects against four types of HPV: 6, 11,16, and 18. A second vaccine, Gardasil 9, was approved by the FDA in 2014. This vaccine protects against four further HPV strains, including HPV 31, 33, 45, 52, and 58. Gardasil 9 is the only HPV vaccine available in the United States today.

The Gardasil vaccines work by using the protein shell of each HPV strain. This shell does not contain viral RNA or DNA, so it causes an antibody response in the body but does not cause disease. The antibodies bind to the HPV virus and prevent the virus from infecting cells. The vaccine is administered in a series of two or three shots.

Before the first Gardasil vaccine was approved, it was thoroughly researched and went through several clinical trials over the course of ten years. The vaccine was tested on more than 20,000 females in 33 countries, and 4,000 males in 18 countries. 

Clinical trials showed that the Gardasil vaccine is nearly 100 percent effective in preventing cell abnormalities in the cervix by HPV strains 16 and 18. The studies also showed the vaccine is 90% effective in preventing genital warts and lesions from forming as the result of HPV strains 6, 11, 16, and 18. Clinical trials on Gardasil 9 showed the vaccine is nearly 100 percent effective in preventing cell abnormalities by HPV strains 31, 33, 45, 52, and 58 as well.

Further clinical trials have examined how effective Gardasil 9 is in different age groups. The studies have found that a greater immune response is created in younger adolescents. Therefore, it is recommended that boys and girls get vaccinated at age 11 to 12.

Vaccine rates vary greatly from state to state. In the United States as a whole, 54.2 percent of teens were up to date with HPV vaccines as of 2020. HPV vaccination rates are unfortunately much lower than that of other childhood vaccines, and further work needs to be done to ensure more children and teens get vaccinated. Still, HPV has reduced greatly in the United States since the vaccine was implemented, with 4.3 percent reported among girls ages 14 to 19 in 2009 to 2012, compared to 11.5 percent in 2003 to 2006.

While the HPV vaccines already show great progress, the research is not done! Clinical trials in Costa Rica and Australia are currently studying whether the vaccine could be effective in a single dose. Other studies are examining the efficacy of the vaccines over an extended period to determine the total duration of HPV protection from vaccines. 

Finally, ongoing clinical trials are working to develop and test the efficacy and safety of a therapeutic HPV vaccine. Instead of preventing HPV infection, this vaccine would prevent cancer in women previously infected with HPV. This type of vaccine stimulates the body’s immune system to target and kill infected cells.

A potential area of research that has come about as a result of the COVID-19 pandemic is messenger RNA (mRNA) vaccines. These vaccines teach the body’s cells how to make a protein or piece of a protein that triggers an immune response inside the body and produce antibodies to fight off an illness. While these types of vaccines have been researched for decades, renewed interest has occurred because of the new and highly effective COVID-19 mRNA vaccines. 

Multiple clinical trials have launched this year to evaluate mRNA vaccines to treat or prevent certain cancers, such as colorectal cancer, head and neck cancer, melanoma, gastrointestinal cancers, ovarian cancer, breast cancer, pancreatic cancer, and more. These studies illustrate the importance of vaccines and how science and research continue to evolve and launch new ideas and therapies, all to improve health and increase knowledge.