In a lecture at the Technion, Dr. Yotam Bar-On explained how rapid evolution, mutations, and immune evasion allow viruses to outpace the immune system, why vaccines are very successful in some diseases and less so in others, and what we have learned from the Corona era about scientific transparency and effective research directions.
How did evolution shape viral infection? How do humans deal with viral diseases? Why do vaccines work well for one disease and not another? Why are drugs that work against bacteria ineffective against viruses? How optimistic are we about the future? He recently gave a lecture on this at an event held at the Technion, Dr. Yotam Bar-On from the Ruth and Baruch Rappaport Faculty of Medicine.
Evolution, in general, is a long-term process spanning millions and even billions of years – since the beginning of life on Earth about 4 billion years ago. However, when it comes to viruses, evolution is an incredibly fast process – mutations occur, the properties of the virus change, and subsequent lineages of viruses will be more resistant to the immune system and man-made vaccines. Unlike bacteria, viruses are complete parasites that are unable to reproduce without a host cell. They penetrate the cell and enslave it to produce thousands of copies of themselves, that is, new viruses, thus preventing the cell from carrying out its original tasks. At the end of the process, they accelerate the cell’s suicide mechanisms (apoptosis) and lead to its failure.
"The rapid evolution of viruses makes it difficult for the immune system to cope with this rate of change," said Dr. Bar-On in his lecture. "It's evolution against evolution, and both operate at different speeds. This rate of mutation also makes it difficult for us, scientists and vaccine manufacturers, who want the vaccines we develop to be effective over time despite the rapid changes in the properties of the virus. In general, vaccines are our main tool in the fight against viral diseases, and they have already saved hundreds of millions of people, but for many diseases it is a constant effort."
The mechanism on which vaccines are based is the creation of antibodies specific to the virus that attacks us, as well as an immune memory that will help the body respond quickly in the future, if it is attacked again by similar viruses. "A viral disease also creates antibodies and immune memory, and even does it better than vaccines, but we want to be vaccinated without getting sick first, certainly with dangerous diseases."
Dr. Bar-On mentioned mRNA vaccines, which burst into consciousness during the Corona period. "These vaccines, which replace traditional vaccines, are based on the fact that instead of injecting proteins into the body, we inject a "code" into the muscle that causes the body's cells to produce the viral protein themselves. mRNA vaccines are not more effective than traditional vaccines - they are simply easier and cheaper to mass produce, which is why the scientific community is currently working on mRNA vaccines for a variety of other viral diseases."
Dr. Bar-On criticized the conduct of the scientific and pharmacological community during the Corona period. "Today, there is no doubt that the Corona vaccines saved many lives and it was a good thing that they were given, but the responsible parties should have shown greater transparency regarding the side effects, however few they may be. These are very rare side effects that do not detract from the vital importance of the vaccines, but concealing them increased the hesitation about vaccines, created a sense of an aggressive campaign and disdain for the public, and thus harmed the important effort to expand vaccination."
"Another mistake was the excessive investment in research and development channels that were not particularly relevant. One of them was the issue of disinfecting surfaces - huge budgets were invested in this, but today we know that infection through surfaces is almost non-existent in the context of Corona; infections, most of them, occur as a result of aerosols that we emit from our mouths when speaking, sneezing, etc."
Dr. Bar-On explained the differences between different diseases in the context of vaccine effectiveness. "Ultimately, one of the key factors in eradicating epidemics is the rate of evolution of the virus - the lower it is, the more effective the vaccine will be. Some viruses change at a relatively slow rate - for example, measles, polio and smallpox - and so we were able to eradicate them completely or almost completely. For the same reason, the coronavirus vaccine was also so effective. The vaccines for HIV, on the other hand, were not effective because of the rapid change and also because of the virus's ability to enter a dormant state. Fortunately, a combination treatment (cocktail) was developed that stopped the spread of AIDS and significantly reduced mortality from the disease."
Ultimately, Dr. Bar-On returned to the title of the lecture and said: "Evolution is an endless game, and viruses win in the short term thanks to their rapid rate of change - but with the help of science, technology, and vaccines, we can win in the long term."
Dr. Yotam Bar-On is a senior researcher at the Ruth and Baruch Rappaport Faculty of Medicine.He joined the Technion faculty after a postdoctoral fellowship at The Rockefeller University in New York, during which he studied the evasion mechanisms of HIV. In his lab at the Technion, he studies the interaction between viruses and the immune system. His work combines molecular biology, evolution, and advanced computational tools—with the aim of developing new strategies for understanding infectious diseases and improving our ability to cope with the spread of viruses in a changing world.
More of the topic in Hayadan:
One response
The link to the lecture is missing.