Despite public mistrust, most scientists claim that people's refusal to be vaccinated or have their children vaccinated poses an increasing threat to the population's resistance to disease.

Speaking on anti-vaccination tendencies, Infectious Diseases Association Chairman Mehmet Ceyhan told Anadolu Agency (AA) that "vaccine hesitancy" — reluctance or refusal to use vaccinations — is on the increase around the world and in Turkey.

Vaccine hesitant individuals hold varying degrees of indecision about specific vaccines or vaccinations in general.

Vaccine hesitancy is influenced by several factors, mainly from social pressure from society, which includes the spread of misinformation on social media, influential leaders' discourses on vaccine doubt and competence of health professionals and services, social groups and others, Ceyhan said. Anti-vaccination is one of the many factors causing vaccine hesitancy, he said, adding that vaccine rejection is among the consequences of vaccine hesitancy.

Vaccine hesitancy in Turkey

Commenting on increasing vaccine hesitancy in Turkey, Ceyhan said some people claim the substances in vaccines can lead to autism and infertility or cause permanent damage to the body.

Vaccines are much more reliable than medications, he said, noting that vaccines do not cause autism, nor have an impact on children's ability to walk.

The doctor underlined that vaccines cause "no serious" side effects.

Touching on substances like aluminum or mercury in vaccines, he said: "A sum of mercury compounds used to be added to the vaccines to ensure that vaccines were free from bacterial contamination when vaccines were produced in multi-dose bottles."

"But, nowadays, no vaccine contains mercury. Since all vaccines are now in single-dose packages, it is no longer necessary to add a mercury compound," he stressed.

On the other hand, speaking on the allegation that flu vaccines contain aluminum, which causes Alzheimer's, he said: "Aluminum in the vaccine is thousands of times less than the risk level."

He said aluminum in vaccines is low and not hazardous, adding that the total amount of aluminum in all the vaccinations is 5 milligrams.

"However, with drinking water, people consume hundreds of times more aluminum than that," he said. Although vaccination is not compulsory in Turkey, the need for it is strong he added.

Herd immunity

To maintain herd protection against disease within a population, 95% of people must be vaccinated. Turkey's rate of vaccination in 2018 was 96%, while it rose to 98% in 2019, according to Turkey's health ministry.

"No vaccine alone provides a person with full protection from the disease. However, if the majority of society is vaccinated, the vaccine prevents the spreading of diseases," the doctor said.

In this case, he said, the risk of transmission of the disease to the 1-3% of unvaccinated people will be eliminated.

Ceyhan went on to say that once herd immunity is achieved, infection risk is greatly reduced.

"However, if more than 5% of children are not vaccinated, the proportion of unprotected people reaches 6-8%, together with 1-3% of unvaccinated people. In this case, unvaccinated children would be at risk for vaccine-preventable diseases."

For this reason, many countries had to enact laws on vaccination to prevent measles outbreaks, he underlined.

Vaccine rejection threatens public health

The vaccination resistance poses an "increasing threat" in terms of public health, and families should be informed and conscious about this issue, Emine Çelik, a pediatrician at a training and research hospital in Ankara, told Anadolu Agency (AA).

"Unfortunately, some families do not want to get vaccinated due to hearsay information and thoughts that do not have a scientific basis," she said.

Çelik feels sorry that some of her colleagues "misled society" with uncertain information.

"Because, if families realize the importance of vaccination for their children, this negative situation will disappear by itself," she underlined.

The pediatrician stressed that vaccination resistance has become a "serious problem" not only in Turkey but all over the globe, noting that an increase in measles cases in the U.S., European countries and Turkey last year was a result of avoiding vaccination.

"Although adverse outcomes that may occur as a result of vaccination are very rare, they are at a level that should be ignored besides the benefits of vaccination," she warned.

Importance of child vaccination

In the past, when people were not vaccinated, there were mass child deaths, and society struggled with outbreaks, the doctor said.

Çelik highlighted that common childhood diseases in unvaccinated societies have mostly resulted in deaths or severe sequelae and disabilities.

She underlined that the frequency of many diseases can be reduced by vaccinating children.

With vaccinations, she said, it can be ensured that permanent or temporary additional disease complications would occur less frequently.

Çelik said even if vaccinated children get a disease, the vaccination helps to overcome illness in a more "smooth" way.

Noting that vaccinations do not contain substances harmful to children's health, Çelik said: "On the contrary, vaccines are made to strengthen the immune system and to increase the body's resistance to common and serious diseases."

The doctor urged that the vaccinated child develops immunity during a certain period and after encountering the disease factor, "gives a quick and strong response" and gets rid of being sick or suffering from the disease.

"We also question (parents) whether the child's vaccinations are complete while prescribing some treatments, and unfortunately, we have to apply heavier treatments to unvaccinated children while we can treat the vaccinated children more moderately."

Additionally, stressing the necessity and importance of following the immunization or vaccination schedule, Çelik said the schedules are being prepared specifically for each community in line with statistical data and by considering diseases that are common in that community.

She noted that the schedule is subject to changes in line with the needs and scientific data of the society over time.

Modern medicine's greatest success stories

The World Health Organization (WHO) refers to immunization as "one of modern medicine's greatest success stories" and a process whereby a person is made "immune or resistant" to an infectious disease, typically by the use of a vaccine.

The U.N. agency estimated around 19.4 million children globally under the age of 1 did not receive basic vaccines as of December.

"Vaccines stimulate the body's immune system to protect the person against subsequent infection or disease," it says.

The WHO said immunization is a "proven tool" for controlling and eliminating life-threatening infectious diseases, while the organization estimates immunization is estimated to avert between 2 million and 3 million deaths each year, adding that vaccines have prevented at least 10 million deaths between 2010 and 2015.

"It is one of the most cost-effective health investments, with proven strategies that make it accessible to even the most hard-to-reach and vulnerable populations," it said.

Besides preventing sickness and death associated with infectious diseases such as diarrhea, measles, pneumonia, polio and whooping cough, vaccinations hold up broader gains in education and economic development, according to the WHO.

"An additional 1.5 million deaths could be avoided, however, if global vaccination coverage improves," it said.