Putin said on Wednesday that Russian scientists were close to creating vaccines for cancer that could soon be available to patients. The head of state added, “I hope that soon they will be effectively used as methods of individual therapy.”

Several countries and pharmaceutical giants are trying to create cancer vaccines. A vaccine for cancer works by teaching the immune system’s T cells to recognize and kill the cancer cells. Scientists aim to do this by using mRNA, an experimental technology adapted from its use in making COVID-19 vaccines. mRNA is a form of DNA translated into proteins that the body uses as instructions for constructing and operating the cells that make up the immune system.

Scientists take samples of a patient’s tumor and healthy tissue to make a vaccine. They then study how the DNA and RNA sequences differ to identify problem mutations that vaccines can target. This process can be expensive, and a single vaccine can cost millions of dollars to develop.

• Read more: Trump’s Unconventional Fundraising Move: Valentine’s Day Letter to Melania Sparks Campaign Donations

However, some companies and governments are working on a much more cost-effective approach to cancer vaccines. They focus on identifying the early abnormal cells most likely to become cancerous and developing ways of targeting these cells with vaccines or other drugs. One of the pioneers in this area is the Philadelphia-based Basser Center for Research in Cancer, led by Dr Susan Domchek. Her team is testing a vaccine in healthy women with inherited mutations that raise their risk of breast or ovarian cancer. They are also looking at vaccines in people with precancerous lung nodules or other inherited conditions that raise the risk of cancer.

A vaccine targeting mutations in a particular type of cancer is still far from being available to the general public. However, the research is progressing rapidly.