Pertussis vaccination of pregnant women: a mixed methods study investigating uptake and its associated factors (PREVACOQ-2.1)

Whooping cough, known medically as pertussis, is a highly contagious respiratory infection that can be devastating for infants. While the disease is preventable through vaccination, babies under six months old are too young to receive their own first doses of the vaccine. This leaves them vulnerable to severe illness, hospitalization, and even death. To protect these infants, health experts have long encouraged a strategy called "cocooning," where family members and caregivers get vaccinated to create a protective circle around the baby. However, in recent years, outbreaks have continued to occur even in wealthy nations with high vaccination rates. In response, the World Health Organization and health agencies in countries like France began recommending a new approach: vaccinating pregnant women. The goal is for the mother's body to produce protective antibodies that cross the placenta, effectively giving the unborn baby a head start on immunity before they are born.

In 2022, France officially recommended that all pregnant women receive a whooping cough vaccine between their twentieth and thirty-sixth weeks of pregnancy. Two years after this recommendation went into effect, researchers in the Loire-Atlantique region of northwestern France set out to see how well this strategy was working in the real world. They wanted to know not just how many women were getting the shot, but also why some chose to take it while others did not. The team conducted a study involving nearly four hundred women who had recently given birth in three different hospitals. They combined a standard survey with in-depth conversations to understand the human side of the decision-making process.

The results showed that the recommendation was being followed by a significant majority of women. Out of the 388 participants, 306 had received the pertussis vaccine during their pregnancy, resulting in a coverage rate of approximately 79 percent. This was notably higher than the rates for other recommended vaccines during pregnancy; only 37 percent of the women had received the flu shot, and just 16 percent had received a COVID-19 vaccine. The study found that the likelihood of a woman getting the whooping cough vaccine depended heavily on a few specific factors. Women who were having their first child were more likely to be vaccinated than those who had given birth before. Similarly, women with higher levels of education were more likely to accept the vaccine. Perhaps most significantly, women who had already chosen to get the flu vaccine were far more likely to also get the whooping cough vaccine, suggesting that a general willingness to accept preventive care plays a major role.

The researchers also discovered that where a woman received her care and where she was born influenced the outcome, but not in a simple way. The data revealed that the relationship between a woman's country of birth and her vaccination status changed depending on which hospital she attended. For instance, women born outside of France who were cared for at one specific private clinic were significantly less likely to be vaccinated compared to their counterparts at other hospitals. This suggests that the specific environment and practices of a medical center can either bridge or widen the gap in health outcomes for different groups of people.

To understand the reasoning behind these numbers, the researchers spoke with a smaller group of twelve women, listening to their stories and concerns. The conversations revealed that the decision to vaccinate was rarely about a single fact; it was a complex mix of trust, information, and emotion. For many, the primary motivation was the desire to protect their unborn child. They understood that the vaccine would pass immunity to the baby, shielding the infant during those critical first months of life. However, this protective instinct was often weighed against deep-seated fears. Some women worried that the vaccine might cause harm to the pregnancy, such as a miscarriage or birth defects, a fear that was amplified by the intense sense of responsibility mothers feel during pregnancy.

Trust emerged as the most powerful driver in these conversations. Women who felt a strong, supportive relationship with their doctors or midwives were more likely to follow medical advice. When healthcare professionals offered clear, consistent information and took the time to answer questions, women felt more confident in their choices. Conversely, when women encountered conflicting advice or felt that the recommendation was new and untested, they hesitated. The novelty of the recommendation itself was a barrier; some women questioned why they were being asked to do something now that they had not been asked to do in previous pregnancies. They also expressed a desire for more information, noting that they wanted to understand the benefits and risks clearly before making a choice.

The study concluded that while the vaccination rate in this region is high, the decision to vaccinate remains a dynamic process rather than a fixed habit. The researchers found that complacency can set in with subsequent pregnancies, as women who had children before may feel less urgency to take preventive measures. They also noted that the success of the program relies heavily on the quality of the interaction between the patient and the healthcare provider. To maintain and improve these rates, the authors suggest that medical professionals need to provide clear, transparent explanations and listen to the specific concerns of each woman, particularly those who are hesitant or from backgrounds where trust in the medical system may be lower. The goal is to ensure that every pregnant woman feels informed and supported, turning a medical recommendation into a confident choice for the safety of her child.