COVID-19 vaccines are around the world. Researchers explained why none of them are 100% effective

The whole world has been looking forward to the development of coronavirus vaccines for several months. The successful arrival of the vaccines was reported only a few weeks ago by three companies, whose clinical results suggest that their effect ranges from 62% to 95%. The fact that none of the pharmaceutical giants have delivered a vaccine with 100% effectiveness may worry some people. However, the truth is that no vaccine will ever achieve maximum success, writes the Daily Mail.

“The efficiency of seventy or ninety percent is remarkably high,” says Dr. Andrew Preston of the University of Bath in the UK. This means that seven to nine out of ten vaccinated people would not be infected with the coronavirus if they were directly exposed to it. But why can vaccination never provide 100% protection?

“In the development of any vaccine, clinical trials are conducted to see if the substance is effective and, if so, how effective,” explains Will Irving, professor of virology at the University of Nottingham.

The tests are done by giving a vaccine to one group of people and a placebo to another. “So you count the number of cases in each group over a period of time. If you have 25 cases in the vaccine group and 50 cases in the placebo group, the vaccine is 50% effective. That means it has prevented the disease in half of the cases. people in the vaccinated group, “explains Irving.

Although the goal is a 100% effective vaccine, it is virtually impossible to achieve it. The reason is the human immune system itself. “There are too many variations in the population’s immune system for a vaccine to be 100% effective,” Preston explains.

Even in the case of a person, the ability of the immune system to respond to possible infections changes over the course of life. The older a person is, the weaker their immune system and the less vaccines absorb it.

If the effectiveness rate of the three available coronavirus vaccines is 95%, this is actually a very high number. By comparison, the average effectiveness of flu vaccines is 50 percent.

Furthermore, the body’s immune response is weakened by many other factors. Obesity, for example, reduces the effect of the vaccine. This creates an inflammatory condition in the body, which, according to experts, in itself depletes the immune system and reduces its ability to respond to vaccines.

It should not be forgotten that vaccination not only protects the individual, but can also prevent the spread of the disease among the population. The more people can be vaccinated, the lower the risk of transmitting the virus. It is about increasing the so-called collective immunity.

“We have to be honest and admit that no vaccine or medicine is without risk. Until we have more answers, we have to fight misinformation,” adds Preston.