Cases are climbing rapidly, the number has exceeded thousands! The most contagious virus... "One patient can infect 18 people"

Measles, which can be completely controlled by vaccination and even eradicated from the world, has started to climb again in Turkey. According to the Turkish Medical Association (TTB) and expert data, the number of cases has exceeded thousands by the autumn of 2026. While the resurgence of infectious diseases that have been successfully suppressed for many years in the health field increases concerns, experts point out the decrease in the herd immunity threshold and vaccine rejection.

The measles virus, which causes the death of 1 to 2 million children every year in the world, mostly in developing countries, has recently begun to pose a serious threat in Turkey. This virus, which has the potential to be completely eradicated thanks to the fact that the only source of infection is humans and the availability of an effective vaccine, targets both children and adults as vaccine coverage decreases.

Infectious Diseases and Clinical Microbiology Specialist Prof. Dr. Bülent Ertuğrul and Infectious Diseases Specialist. Dr. Songül Özer explained the latest situation in Turkey, the reasons behind the increase and the vital risks of the disease in full detail.

THE NUMBER OF CASES IS INCREASING EXPONENTIALLY: THE CRITICAL THRESHOLD HAS BEEN EXCEEDED IN 2026

Turkey's fight against measles has a long history. Routine vaccination was introduced in 1970 after more than 66 thousand cases and 532 deaths were recorded in 1969. With the major vaccination campaign in 1985, the number of cases decreased to 2 thousand and deaths decreased to zero. Thanks to the strategies implemented since 2003 and the Measles-Rubella-Mumps (MMR) combination vaccine that came into effect in 2006, the disease was kept under control for years.

However, statistics in recent years show that the situation is rapidly reversing. According to World Health Organization data, the number of cases in Turkey, which was only 127 in 2022, increased to 500 in 2023, to 1,500 in 2024, and to around 2,000 in 2025.

By 2026, the climb has gained frightening momentum. The number of cases, recorded as 877 in the first five months of the year, reached 1,103 as of September and 3,000 as of October, according to TTB and expert data.

THE HIGHEST INFECTIOUS VIRUS: ONE PATIENT CAN INFECT 18 PEOPLE

One of the most dangerous features of the measles virus is its extraordinarily high rate of spread.

Specialist Dr. Songül Özer stated that the virus is transmitted through droplets from the respiratory system and rashes, and warned: "Measles is one of the most contagious infections. A single patient can infect 16 to 18 people around him through the droplets he produces. The contagion rate in the community can reach up to 75% to 90%."

Noting that one or more complications develop in approximately 30% of reported cases. Songül Özer emphasized that the disease is now seen frequently not only in children but also in the adult population, and that it progresses severely in adults, increasing the risk of death.

COMMUNITY IMMUNITY THRESHOLD IS IN DANGER

The herd immunity threshold required to prevent diseases with high epidemic potential, such as measles, from spreading in society is accepted as 95%. However, in Turkey this rate has decreased to 92%. It is determined that vaccination rates, especially in big cities, fall below this threshold value.

Specialist Dr. Songül Özer explained the main factors that come to the fore in shaking the immune wall as follows:

Increasing vaccine rejection after Covid-19: Misinformation spread on social media and media in the post-pandemic period, fear of complications that may occur after vaccination, and attributing unrelated diseases to the vaccine fueled vaccine hesitancy.

Irregular migration and unregistered population: In Turkey, MMR vaccine is administered free of charge to all children and registered immigrants in Family Health Centers within the scope of the National Immunization Calendar. However, unregistered migration and not knowing the vaccination history of migrants and not being able to track them create a significant security vulnerability.

Missing dose and immunity problems: Leaving the vaccine, which requires two doses, in the first dose or insufficient personal immune response even if two doses are administered, paves the way for cases of cases.

Songül Özer added that although childhood vaccinations are among the practices that must be carried out in accordance with the legislation in Turkey, families can legally refuse vaccination "at their own will" and there is no criminal sanction for this.

According to the National Immunization Program for measles vaccine, the first dose is given at the 12th month and the second dose is given at the age of 4-6 or usually in the first grade of primary school. The protection rate in children who receive a single dose of vaccine is approximately 95%, and this rate increases to 97-99% after the second dose. In other words, there is a 1% to 3% chance of getting measles after vaccination.

Prof. Dr. Bulent Ertuğrul

HOW DOES MEASLES PROGRESS IN VACCINATED AND UNVACCINATED CHILDREN?

Prof. Dr. Bülent Ertuğrul detailed the disease picture in unvaccinated children as follows:

Vaccinated children: Even if a child who has been vaccinated with two doses encounters the virus, he either does not get the disease at all or gets over it with extremely mild symptoms. The vaccine completely prevents the virus from damaging vital organs in the body and developing fatal complications.

Unvaccinated children: After an incubation period of approximately 10 days, the disease begins with high fever up to 40°C, runny nose, redness of the eyes and cough. At this stage, white lesions called "Koplik spots", specific to measles, appear in the mouth. Then, red rashes appear, starting from the face and spreading to the whole body. The child experiences loss of appetite and severe weakness. The patient continues to transmit the virus to those around him from the moment the first symptoms appear until the rash disappears.

RISK OF PNEUMANE, BRAIN INFLAMMATION AND FATAL SSPE

Measles is far from being a simple childhood rash disease. In cases where complications develop, the condition may rapidly worsen.

Prof. Dr. According to the information provided by Bülent Ertuğrul, 50-60 out of every 1,000 children (5-6%) who have measles develop pneumonia, while one out of every 1,000 children develops acute encephalitis (brain inflammation).

The most frightening complication of the disease is Subacute Sclerosing Panencephalitis (SSPE), which occurs when the measles virus settles in the brain and has no cure. This fatal situation, which was seen in one in every 100 thousand children in the pre-vaccine period, was reduced to one in 10 million thanks to widespread vaccination. However, in unvaccinated societies, the risk is still as high as one in 100 thousand.

SSPE DISEASE PROGRESSES SNEAKY AND DESTRUCTIVE

Prof. Dr. Ertuğrul explained the 4 stages of SSPE, a slow-going brain inflammation that can occur months or years after measles infection, with the following words:

- Stage 1 (Early period): Significant personality and behavioral changes begin in the child. Learning difficulties and a sudden decline in school success are notable. It is extremely difficult to make a diagnosis during this period and the disease can be confused with different neurological disorders.

- Stage 2: In this period, which can last from a few months to a year, muscle twitching, difficulty speaking and involuntary movements in the body occur.

- Stage 3: In this stage, which begins after the first year, severe conditions such as severe epilepsy-like seizures, muscle contractions, difficulty swallowing and eating, and the inability to walk are experienced.

- Stage 4 (End stage): The patient enters a coma state. As a result of affecting vital centers in the brain, the disease unfortunately ends with death within 1 to 3 years.

JOINT CALL FROM EXPERTS: "VACCINE IS A RIGHT TO HEALTH"