• Marcio Alvarez-Silva, PhD

Vaccines and cancer

Atualizado: 11 de Dez de 2020

The concept of the vaccine is precise: it is a biological substance that stimulates the acquired immunity to a disease. Vaccines are an essential therapy to boost the immune system with the production of antibodies against the infection.

When a person uses a vaccine, he or she is protecting or preventing the disease.

Vaccines were an important advance in science.

Often the vaccine significantly attenuates the development of the disease. If one person who has been vaccinated acquires a virus, he does not fully develop the disease. If the infection occurs, it will be alleviated with few or no symptoms. Usually, vaccination offers important protection avoiding the viral infection. This protects the person to have a critical infection to evolve and develop a severe health condition.

Vaccines saved millions of lives and helped eradicate serious diseases such as smallpox in the world. Smallpox killed almost 500 million people in the 20th century. The last natural case of the disease was diagnosed in October 1977, prompting the World Health Organization to certify the disease's eradication in 1980.

This advance has only been achieved due to mass vaccination against the smallpox virus.

Cancer is a complex disease and can affect several different types of cells and tissues. What makes the development of a vaccine against the disease still very complicated. We know that cancer does not refer to a single condition. We are talking about a large set of cellular disorders that have the hallmarks defined as the modification in cell proliferation, infiltration, and dissemination to many tissues. We are talking about many different diseases that have as characteristic the alteration in cellular proliferation resulting in neoplastic progression.

Unfortunately, a vaccine against cancer is not yet available.

Patients always have some questions. Would it be possible in the next future to develop vaccines with the potential to produce cancer immunity? If the patient already has cancer, would a vaccine be effective?

These questions arise from the advances that have been made in the development of modern vaccines.

We currently have some important vaccines that can help prevent some forms of cancer. They are not cancer-targeted vaccines, but their effects in preventing some diseases would help to prevent some types of cancer.

We have vaccines against hepatitis B and the human papillomavirus (HPV). We know that chronic infection with the hepatitis B virus favors the development of liver cancer. On the other hand, there are more than 150 types of HPV. The International Agency for Research on Cancer (IARC) has classified 12 HPV types as carcinogenic and can cause cancer of the cervix, vulva, vagina, penis, anus, and oropharynx.

At least in these cases, we can consider that the currently available vaccination can be an important preventive measure to avoid at least the onset of some types of cancers.

As science advances, new strategies to stimulate the immune system with smarter vaccines are developed. The immune cells can become more resistant to disease and even destroy tumors already established in the patient. That is the immunotherapy against cancer.

Immunotherapy against cancer is the field where the development of smart vaccines is advancing. Two scientists working on cancer immunotherapy were Nobel laureate with the 2018 Nobel Prize for Medicine: the American James Allison and the Japanese Tasuku Honjo. Both scientists use biological substances to stimulate the immune system. Thus, the patient's immune cells acquire the ability to fight and even destroy the cancer cells. This technology of smart vaccines is still very recent and targeted for a few cancers.

The good news is that with these studies, the range of possibilities will expand and in the coming years, we will evolve and accurate the smart vaccine technology to different types of cancers. With the development of scientific research new treatments will be available in the forthcoming years. With this new vaccine technology, many patients can be cured in the next future.

Paradoxically there has been a worldwide movement against vaccination. This movement has tragic results, as unvaccinated individuals have no immunological capacity to resist infection and may even have a more severe form of the disease since their immune system has not been adequately stimulated to combat or prevent the disease. The results can be fatal.

Perhaps the saddest example of this movement against vaccination is the Bray Payton case. She was the editor of the digital magazine "The Federalist." She said in her Twitter that vaccination is "from the devil" during an immunization campaign against whooping cough in the United States. Bray Payton died at age 26 victim of H1N1 flu, aggravated by meningitis on December 28, 2018. In both cases, there are vaccines would that help prevent the diseases that victimized Bray Payton.

The myth that vaccines are harmful or that even produce diseases are based exclusively on the lack of knowledge that the effect of boosting the immune system can result in symptoms that are like the viral infection with fever and discomfort. However, this only demonstrates that the immune system is learning and improving with the vaccination, responding to the vaccine's stimulus.

Immune system stimulation through vaccination can never be confused with a disease.

Vaccines heal or prevent diseases. They do not cause them.

Very soon we will have smarter, efficient and targeted vaccines for various types of cancer.

Do not let the myth that has spread out about vaccines hinder the path that is being paved for the treatment and cure of cancer through immunotherapy.

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