Researcher warns of whooping cough spike as disease spreads throughout Israel
Infectious disease expert says Israel is in the middle of an outbreak that occurs every four years; Health Ministry urges vaccination for pregnant women to lessen spread
Reporter at The Times of Israel
The death in June of a 5-week-old baby from whooping cough (pertussis), and a spike in the number of reported cases around the country are signs that Israel is seeing a spread of the contagious, yet preventable, disease.
According to the Health Ministry, there were more than 2,480 cases in the first half of 2024 compared to 1,795 in all of 2023. The illness was concentrated in Jerusalem last year; this year’s outbreak has spread to central Israel and Haifa.
In a 2020 study about the periodicity of pertussis that appeared in Science Direct, Prof. Dan Yamin, head of the lab for Digital Epidemiology and Health Analytics at Tel Aviv University, Prof. Erez Shmueli and Dean Langsam discovered that since the 1950s, an Israeli outbreak of pertussis has occurred every four years. There were peaks in 2016, 2020, and now, in 2024.
“From now until the end of 2025 is a dangerous time because we’re at the peak of the four-year cycle,” Yamin said.
Israeli statistics mirror international numbers, even in countries with high vaccination coverage, said Yamin, an expert in epidemiology and infectious disease modeling.
“It is important to note that pertussis in Israel, similar to worldwide trends, is cyclical, with relatively high levels of incidence approximately every four years,” said a Health Ministry spokesperson.
A first infection in young infants and the unvaccinated is more “virulent and dangerous” than for other populations, Yamin said.
Approximately 98% of Israeli children received the pertussis vaccinations in Israel but in recent years, that level has dropped to about 92%, said Yamin.
If the percentage of vaccinated people dips below 92%, then there is a decrease in herd immunity and a breakout of the disease.
Yamin’s study found that vaccination during pregnancy can “lower the 20-year increase in the incidence of severe cases of pertussis,” he said.
In light of the growing numbers, the Health Ministry is again urging pregnant women to get vaccinated against pertussis during their third trimester to protect their children.
Since babies do not receive vaccinations against pertussis until they are two months old, the ministry stresses the importance of pregnant mothers receiving the pertussis vaccination in their third trimester.
Pregnant mothers who are vaccinated produce antibodies that they pass on to the fetus via the umbilical cord. These antibodies provide the newborn with some protection until they are old enough to receive the vaccination.
Yamin said that his study showed that when pregnant women are vaccinated, the overall number of severe cases of pertussis decreases.
The vaccination is required during each pregnancy to protect each child, the Health Ministry said, adding that the mother of the baby who died in June was not vaccinated, nor was the baby.
In the year before and after the peaks, there are also outbreaks, as happened in the spring of 2023. At that time, the Israeli Midwives Association issued a statement advising all pregnant women in weeks 27-36 to get a pertussis vaccination.
The dangers of whooping cough bacteria
Pertussis is a respiratory illness caused by a type of bacteria called Bordetella pertussis. The disease is only found in humans, and its popular name is based on the donkey-like wheezing sounds that infected people make while coughing and being unable to catch their breath.
According to the US Centers for Disease Control and Prevention, whooping cough bacteria attach to the cilia, the tiny, hair-like extensions that line part of the upper respiratory system. The bacteria release toxins that damage the cilia and cause airways to swell.
Whooping cough bacteria spread easily in the air when someone with the disease coughs or sneezes.
Babies younger than 1 who are unvaccinated are at greatest risk for getting whooping cough in its most virulent form, said Yamin.
The disease could cause apnea, life-threatening pauses in breathing, that then lead to cyanosis (turning blue). It is estimated that one in 100 newborns hospitalized with pertussis die.
What’s more, one in 20 will sustain brain damage because of low oxygen levels and the toxin generated by the bacteria that causes pertussis.
Protection against pertussis is given as part of the DTap or Tdap combination vaccines, both of which protect against pertussis, tetanus, and diphtheria. The vaccine schedule for infants and children involves six shots between the ages of two months and 13 years, given initially in baby clinics and later in school.
Over time, immunization becomes less effective. The ministry advises adults to receive a pertussis booster shot after the age of 18 to maintain protection, especially for those who work in healthcare settings.
In serological studies conducted in Israel, about 3% of the population is exposed to pertussis annually. This number corresponds to 270,000 people every year, Yamin said, “which is quite substantial.”
Yet people might not be aware they have the disease because “a lot of cases are asymptomatic or less severe” due to the efficacy of the pertussis vaccination, he said.
Their symptoms might be mild, but they are carriers of what is a highly contagious disease. From his research, Yamin has found that people with COVID could infect an average of three people, whereas people with pertussis can infect 10 people.
Choosing not to vaccinate
Vaccination coverage is also not spread uniformly among the Israeli population. There are areas in the country with a higher number of young infants and where pregnant mothers are not vaccinated. These areas have the most severe cases.
Yamin said the drop in vaccinations might be attributed to a rising “distrust in vaccines” since COVID.
“There are severe cases of pertussis among unvaccinated babies,” Yamin said. “It is those cases and hospitalizations that we clearly want to prevent.”
Not all Israelis agree with that assessment, however.
“The baby’s immune system is new and in good condition,” said Mai Drami, an Israeli mother of a 2-year-old son who lives near Nahariya. “Vaccinations place an unnecessary burden on the newborn’s immune system.”
Some Haredi parents in areas that have low vaccination rates are not ideologically opposed to vaccinating but face other hurdles, said Israel Pediatrics Association chair Prof. Zachi Grossman.
Contagion rates are higher because of large families, he said, and some parents “have difficulty getting all their children to clinic appointments.”
The Health Ministry has taken steps to raise awareness of the importance of vaccination, a spokesperson said, including increasing the administering of vaccines and reaching out to the general public about vaccinating their children as well as pregnant women.
Some countries recommend that adults receive a booster shot if they have not had one in the past 10 years or if they work with infants. Yamin said that the analysis of data from his study shows that older adults have partial protection from their original vaccines.
“They also have a lower chance to become infected in general due to reduced contacts, making the overall risk low,” he said. “If infected, they have less chance of undergoing a severe outcome.”
Yamin said that infectious diseases remain “one of the greatest risks to a global catastrophe.”
During the 20th century, the World Health Organization (WHO) estimates that before its eradication, smallpox caused between 300 million and 500 million deaths globally.
“Look at the numbers,” Yamin said. “That’s a lot of deaths from one infectious disease.”
