Studies on the cost-effectiveness of rotavirus vaccines might sound like pretty dry pursuits. Though I find science fascinating, nothing makes my eyes glaze faster than talk of monetization and math. But when I learned about the paths that investigators tread to learn how a new vaccine will impact communities where diarrhea is a matter of life or death, I found out that cost-effectiveness has a pretty personal side.

I asked Deborah Atherly and Mercy Mvundura, both health economists at PATH, to share their experiences conducting these studies and explain why costing research is essential to vaccine advocacy and saving lives. They are currently conducting cost-of-illness studies on childhood diarrhea in Rwanda and Malawi.

What does cost-effectiveness mean in the context of new vaccine introduction?

Deborah Atherly: Cost-effectiveness analysis is a method to help decision-makers understand the true value of a vaccine; that is, what are the benefits, and how much does it cost to realize those benefits?

So a main objective is to gather data to make the case for new vaccines to policymakers.

DA: The data help them understand how important vaccination is, particularly in areas where vaccination rates are low. For example, we did a study in Senegal for Hib meningitis and found that the direct costs to families for one child's illness literally equaled the average annual income. Yes, Hib meningitis is a more rare occurrence than childhood diarrhea—but not for the child who gets it, not for their family.

We were able to communicate this finding to the government, and they walked away saying, “Wow, we really need to make sure that people can access the Hib vaccine.” They were a bit startled by the cost.

A sad reality that we see in these studies, though, is that the people who show up to the hospital are the ones who can afford it. Who we're missing are the kids who die because their families can't afford care. That makes universal vaccination all the more important.

Mercy Mvundura: You see this in the studies that we're doing, where you ask families about the sources of funds to pay for hospitalization, and you can see that even with a simple diarrhea hospitalization, they may have to sell assets, rely on support from their communities, borrow from relatives, or tap into savings—if they have them—in order to be able to pay for a hospitalization.

What are the steps to gather these data from families? Walk me through the study methods.

DA: In Rwanda and Malawi we are conducting cost-of-illness studies, working with the Ministries of Health, WHO and also in partnership with the US CDC and University of Liverpool, respectively, which are conducting disease surveillance. The CDC and Liverpool researchers identify all child diarrhea cases that come into a hospital. If their participants also consent to enroll in our study, our investigator asks caregivers a series of questions about how long a child's been ill, where they were seen before the hospital, what costs they have incurred to date. These are clinic costs, but we also ask about transportation costs to get to the hospital.

When the child is in the hospital, we collect information from their medical record: the medications they were given, staff time in caring for them, lab tests. We try to cost out all parts of their hospital care.

MM: Afterwards, when they are discharged, we follow up with caregivers to understand how much they paid for the hospital visit and the sources of the money they used to pay. We also try and capture information around their economic status. We ask whether they missed work, how many days, what is their salary.

Finally, we collect data from the hospital billing department to bring it all together.

DA: Ideally, we want to determine, from start to finish, the average cost of treating a child for diarrheal disease. We break that down into household costs and costs borne by the government or system. Thanks to the parallel CDC and Liverpool studies, we will also know the rotavirus status, so we can stratify according to whether rotavirus or another cause is responsible for the diarrheal episode.

MM: We also can look at the length of hospital stay, to see whether it differs between children who are diagnosed with rotavirus versus other types of diarrhea.

How do you relate that back to explaining to a government how introducing rotavirus vaccine is going to offset these costs?

DA: We use this cost-of-illness data to discuss cost-effectiveness. Health and finance ministers have to consider how much a new vaccine is going to cost. But what they might not think about are the potential cost offsets. That's the perspective that our data provide: a very quantitative estimate of the financial impact: reduced costs through introducing rotavirus vaccine.

We take the cost of vaccine minus the costs that would be offset to determine the total net cost of vaccine introduction. Then you put that into the equation against the actual benefits of the vaccine. We take our cost per hospitalization and multiply it by the number of hospitalizations averted, drawing from the surveillance data that the CDC and Liverpool are collecting. This helps us reach a financial estimate of what we think a country could save with universal, routine rotavirus vaccination.

Because Rwanda and Malawi have already introduced rotavirus vaccines, how are the data useful to them, and how are they useful to other countries?

DA: In a couple years, several countries will graduate beyond the GAVI Alliance subsidy for rotavirus vaccines and need to take on the full cost. As the bill goes up, Ministries of Finance will want to know, what is the value? Data on how many deaths can be averted speak volumes. Cost-effectiveness helps to show that. We also include information on how the demand for public health services will go down because fewer children are coming to the hospital with severe diarrhea. We make the case for keeping GAVI-funded vaccines in the public health system when the country's investment costs increase.

In your research experiences, have there been findings that surprised you?

DA: When we ask what kind of work they are missing, many mothers say “childcare.” That is so much more real than I ever imagined. Families typically don't just have one child. They have many children. If one is sick, then to take them to the hospital, which may not be down the street, they're leaving their other children with someone else. Here, we think of it differently. We often can easily find care or pay someone to watch other children. These mothers have to make sacrifices we might not consider in terms of their other kids. We also find that many women won't go to the hospital until the child is literally close to death, because it's such a big sacrifice to leave, find care for the other children, and find the transport to get to the hospital.

MM: And our perspective is coming from a society that generally undervalues staying at home. When you start trying to quantify “productivity loss” for a primary caregiver, you may think to apply minimum wage, as opposed to someone who has a set salary.

Which most stay at home mothers would argue is not enough.

DA: Yes, exactly. That's universal no matter where you live.