SPH Study Aims to Help Developing Countries Curb Childhood Pertussis.

A BU School of Public Health researcher is leading a multi-year research study funded by the Bill and Melinda Gates Foundation to investigate ways to reduce the nearly 200,000 childhood deaths caused by pertussis.

The $1.2 million grant for the initial phase of the study will help track the incidence of pertussis in the first six months of life, when infants are most susceptible to the disease, said Christopher Gill, an associate professor of global health who heads a BU research team working in Zambia.

“We’re focused on novel ways of reducing child mortality that can be affordable. One idea that has gotten a lot of traction is maternal vaccinations as a way of generating immunity in the child,” Gill said.

Prior field experience has shown that immunizing mothers against influenza and tetanus can help reduce the incidence of these diseases in very young infants. Tetanus vaccines for expectant mothers are already part of the prenatal health routine in many developing countries like Zambia, where Gill’s team plans to swap out the current tetanus vaccine in favor of the combination tetanus, diphtheria and pertussis vaccine (TDAP).

The TDAP vaccine used in the US is fairly expensive, Gill said, at an average of $18 per shot. “That’s not going to work in Africa,” Gill said, “So we’ll likely be searching for partners to help develop a cheaper version of the vaccine, but right now we’re just trying to prove the principle.”

The study will be conducted at three separate research sites: one in Zambia run by BU, one in Pakistan handled by a team from Emory, and a site in Johannesburg run by University of the Witwatersrand. Each site will work in coordination with the other two, but all will be funded independently.

For the first year, each research team will track a birth cohort of about 2,000 babies at each site to see how much pertussis, also called whooping cough, actually occurs at the specific locations.

“We don’t know much about pertussis in Zambia because there haven’t been any solid ground-level studies on it. We suspect there’s a lot but we’ll need to do the epidemiological research in order to calculate our sample size appropriately,” Gill said.

Every two weeks, babies will receive nasal swabs to detect the presence of DNA sequences of the Bordetella pertussis bacterium. Researchers will also track the HIV status of mothers to assess any possible connections between pertussis and compromised immunity. One of the reasons the Gates Foundation wanted the run the study in Zambia is the relatively high prevalence of HIV among women, Gill said.

The Zambia site alone expects to conduct about 70,000 swabs over the course of the year, Gill said.

Once investigators have a more accurate measure of the incidence of pertussis in babies, they expect to be able to launch randomized trials in 18 months. Gill said the research teams will likely use two types of pertussis vaccines to see whether both are effective.

“At the very least we’re going to know a lot more about the epidemiology of pertussis in very young infants,” Gill said. “Right now we know next to nothing.”