Truth and myths about vaccines
Oncology, infection and decreased immunity
Inna Finochka, TASS
Millions of people's lives depend on vaccination. This will continue as long as there are viruses and other diseases on Earth that can now be controlled with vaccines. In Russia, the most common of them are included in the National Calendar of Preventive Vaccinations. However, a large number of people delay vaccination or refuse it altogether.
According to the World Health Organization (WHO), distrust of vaccination can be the result of a number of factors: doubts about safety, distrust of specialists, lack of information.
Epidemiologists, in turn, note that as soon as the number of vaccinated people decreases and the population immunity weakens, the virus raises its head. An example is measles outbreaks in Europe and Ukraine this year.
How vaccination works, why it should not be neglected and what myths about vaccines exist, TASS was told by Nikolai Briko, chief freelance epidemiologist of the Ministry of Health of Russia, Head of the Department of Epidemiology and Evidence-Based Medicine of the I.M. Sechenov First Moscow State Medical University, and Yuri Vasiliev, Acting Director of the State Research Institute of Especially Pure Biopreparations of the FMBA of Russia.
How does vaccination work?
In fact, vaccination is the training of immunity. A person is injected with a weakened version of the virus or its component, and the immune system attacks in response and remembers how it did it. The antibodies that appear as a result of vaccination, when they meet the virus again, know how to react, and do it much faster. Immunity is developed against a specific disease.
What is immunity?
Immunity is of two types: innate, it is also specific, and acquired, which occurs as a result of a disease (post-infectious) or as a result of vaccination (post-vaccination). The latter, in turn, is divided into individual and population. When a person is vaccinated, for example, against measles, he develops an individual immunity to this disease.
"Population immunity, or collective," explained epidemiologist Brico, "is the percentage of immunized people in a collective, city, country who have immunity to a particular pathogen. It is determined by special tests, each vaccine has its own set of tests. Guaranteed protection against infectious disease provides 95% coverage of the population with immunization."
What are the vaccines?
Vaccines can be live and inactivated. Weakened strains of pathogens are used to create live vaccines. And the inactivated vaccine consists of killed virus strains, so it is also called "killed". The most common method of administering vaccines is injection, but there are oral (drops) and nasal vaccines.
WHO estimates that immunization can prevent up to 3 million deaths from viruses annually.
MYTH 1: the risk of complications from the vaccine is higher than the risk of contracting an infection
"Any medical intervention can lead to adverse reactions. Unfortunately, this is a fact, – Yuri Vasiliev notes. – Now there are no medicines and procedures with absolute safety. As for vaccines, the benefit-risk ratio it is very much outweighed in the direction of benefits."
According to the Center for Disease Control and Cessation (USA), complications as a result of vaccination occur relatively less frequently than complications as a result of previous diseases.
"When using a live vaccine, the risk of an adverse reaction is slightly higher than when using an inactivated one," Vasiliev added. – Therefore, it is advisable to use them in those conditions where the probability of getting sick without vaccination with a dangerous disease is extremely high. We are talking primarily about such life-threatening diseases as yellow fever and polio." For example, in countries where the risk of wild poliovirus is reduced, the live oral polio vaccine is replaced with an inactivated polio vaccine. Vasiliev also noted that for vaccines that are included in the national vaccination calendar (DPT, measles, rubella, mumps, influenza and others), the risk of complications is minimal.
MYTH 2: vaccinations are ineffective and weaken the immune system
According to the acting director of the State Research Institute of Especially Pure Biological Products of the FMBA of Russia, an inactivated vaccine that has passed all stages of quality control and entered civil circulation, in principle, cannot weaken immunity and give infection, because it is inactivated. "If we talk about the example of the flu vaccine: it takes two weeks for immunity to form, so it may well be a situation when a person was vaccinated, and the next day he showed symptoms of the disease. This means that a person has already been infected a few days ago, the incubation period has passed, and the cause of this infection is not related to the vaccine, it is due to the fact that it simply overlapped in the temporal plane," Vasiliev explained.
He noted that in each specific case, if we are talking about vaccination during the epidemic season, it is necessary to find out what exactly a person is sick with. "Maybe it's not the flu. Although sometimes there are cases when a new strain of flu appears during the epidseason. There are cases when doctors do not comply with contraindications and vaccinate. Nevertheless, even in this situation, even partial immunity will allow avoiding severe infection, hospitalization, complications," he said.
MYTH 3: Vaccines contain dangerous substances, such as mercury
Concerns about the presence of an organic compound containing mercury in vaccines – thiomersal – owe their appearance to an environmental activist, the nephew of American President John F. Kennedy, lawyer Robert Francis Kennedy Jr. In 2005, his article "Lethal Immunity" appeared in Rolling Stone magazine, in which the author claimed that the government was hiding the link between thiomersal and autism in children. According to WHO, some vaccines do include thiomersal. At the moment, it is used as a preservative for vaccines in multi-dose vials (when several people are vaccinated from one vial with different syringes). At the same time, according to the Center for Disease Control and Cessation (USA) and WHO, there is no evidence that the amount of thiomersal used in vaccines provokes autism or poses another health risk.
In Russia, Roszdravnadzor is responsible for checking the quality and safety of immunobiological drugs, since 2019 the agency intends to monitor each batch of vaccines, in accordance with WHO recommendations.
MYTH 4: it is not necessary to vaccinate against those diseases that do not exist now
Epidemiologist Brico is convinced that vaccines have become hostages of their success in some way: now there are no epidemics that occurred before the invention of vaccines. But even now there is a danger that the pathogen may be introduced from other territories where diseases are common or where there is a chance of getting sick.
An example from modern reality: the incidence of measles in Europe, which increased in 2017 and continues to grow in 2018. Brico recalled how in 2009 in Tajikistan, against the background of serious defects in the organization of immunization against polio, an epidemic caused by "wild" a virus imported from India. "Vaccination against smallpox, for example, we stopped only when the world became convinced that the smallpox virus does not exist in nature," Brico added.
MYTH 5: if all children at school or kindergarten are vaccinated, but my child is not, then nothing terrible will happen, we are protected
"This is a very dangerous position," Nikolai is convinced Brico. – If the coverage decreases, the risk increases that the infection will spread rapidly in the team. Parents think about possible complications, which happen extremely rarely, but do not think about the very real danger of contracting an infection, the causative agent of which circulates among the population or may be introduced from other territories."
After all, no one guarantees 100% that, for example, a person with chickenpox, flu, rubella or measles will not be on an airplane with a closed ventilation system.
MYTH 6: Vaccines cause autoimmune diseases
When the cells of the immune system begin to attack their own body, this is called an "autoimmune disease". The risk of developing autoimmune diseases associated with vaccination is still theoretical – there is still no data that would confirm that there is a link. Although the role of vaccines in the occurrence and development of autoimmune diseases has been discussed for a long time.
Therefore, at the moment, experts believe that there should be no choice between the proven effectiveness of vaccines and the theoretical risk of developing autoimmune diseases. Clinical studies comparing the incidence in vaccinated and unvaccinated groups of people did not show an increase in autoimmune diseases in those who had previously been vaccinated.
MYTH 7: Vaccines cause cancer
Vaccination can reduce the risk of developing certain oncological diseases. Thus, vaccination against human papillomavirus (HPV), which causes cervical cancer, is already included in the national calendars of several dozen countries. WHO recommends this vaccination among measures to combat non-communicable diseases worldwide. In general, according to WHO, approximately one in four cases of cancer in the world (in low- and middle-income countries) is associated with infections that cause cancer, hepatitis and HPV.
"Today, the success of vaccinology and biotechnology is fantastic,– said epidemiologist Briko. – With the help of vaccines, we can not only prevent infections. The principal possibility of designing vaccines against allergic and autoimmune diseases, oncological and somatic diseases, drug addiction, smoking is shown." According to the expert, at the moment about 500 vaccines for various pathological conditions are being developed in the world.
MYTH 8: natural immunity is stronger than what occurs during vaccination, so it is better to take the child to a "smallpox party" and "to visit rubella"
This is not true: someone will be lucky and he will suffer from the disease in a mild form, someone in a severe form, and someone may have serious complications. Experts noted that it is impossible to predict this, it is a dangerous way to get immunity from infection. "In some cases, infections are very severe, and they are the main cause of disability of children," explained the chief epidemiologist of the Ministry of Health of Russia. – Therefore, in no way would I advise parents to do this with their children. Vaccination forms protective immunity in a much safer way. The frequency of complications and deaths when a child is infected with "wild" a variant of the pathogen, in comparison with post-vaccination complications, is incomparable."
MYTH 9: you only need to be vaccinated against dangerous diseases
According to Briko, it is necessary to make vaccines against all infections that are indicated in the national calendar of preventive vaccinations, and when planning trips abroad, get vaccinated against infections registered in the country where you are going.
MYTH 10: you can not get a flu shot
Annual vaccination against influenza helps to prevent morbidity and significant socio-economic damage. Influenza is a severe infection with serious complications, especially in children, pregnant women and the elderly with various chronic diseases. "Elderly people, people with chronic diseases should be vaccinated against influenza and pneumococcal infection, among them the highest risk of complications," the epidemiologist added.
The material also used data from WHO, the American Center for Disease Control and Cessation, the Ministry of Health of Russia and Rospotrebnadzor of the Russian Federation.
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