Digging into data to illuminate how vaccines reduce dependence on antibiotics Date: 09/15/17
By Alice Callahan
Vaccines and antibiotic resistance are two hot topics in health news, but they’re not often part of the same story. I had the fun and challenging project of combining the two in a recent piece for FiveThirtyEight: “The Fight Against Antibiotic-Resistant Bacteria Might Start With Vaccines.” I pitched this to FiveThirtyEight at the AHCJ conference in Orlando this spring, and it was published in August.
The idea for this story came from a conversation with a pediatrician in Portland, Ore., Joel Amundson. He told me that when he talks to vaccine-hesitant parents, he often brings up how vaccines reduce the chances that a child will need to be treated with antibiotics. In this era of growing concern about antibiotic resistance and cultivating a healthy microbiome in kids, he says many parents recognize this as a major benefit.
It was an angle that I hadn’t seen explored before, and I wanted to learn more. It almost seems too obvious that vaccines would reduce antibiotic use by preventing bacterial infections. But was there data to support this idea?
The answer was yes, but it required some digging. Most of today’s vaccines were first developed decades ago, before there was much concern about antibiotic resistance. Vaccines for diphtheria and pertussis were developed before penicillin was even available. The vaccine for Haemophilus influenzae type b (Hib) was first released in the mid-1980s, but the focus then was the number of children’s lives saved, not antibiotic treatment averted. It wasn’t until the pneumococcal vaccine, first added to the infant schedule in 2000, that researchers tracked antibiotic-resistant infections and antibiotic use before and after the introduction of the vaccine. (There was lots of data on that one, which I included in the piece.)
Even where antibiotic data was limited, it’s fair to say that since vaccines clearly prevent bacterial infections, they decrease the use of antibiotics to treat them. In the piece, we used a table and bar graph to show data from a 2014 Pediatrics study that estimated the number of bacterial and viral infections prevented by the recommended childhood vaccine schedule. One of the highlights of writing for FiveThirtyEight was getting to work with Ella Koeze, a visual journalist on staff, to create illustrations for the piece. I provided the datasets, and she brought them alive as graphs more than I could with text alone. (Koeze also describes her role at FiveThirtyEight as data editor or graphics editor.)
We also used data from the CDC for graphs showing the drop in Hib and invasive pneumococcal infections that occurred after the release of those vaccines, starting with data from the Active Bacterial Core surveillance (ABCs) site. For Hib, the ABCs data didn’t go back to the pre-vaccine era, so I had to dig through MMWR reports and contact a press officer at the CDC to complete the dataset. I also used the CDC’s VaxView page as a source for Oregon’s immunization rates – it’s an excellent resource for journalists looking for data on national and state immunization rates.
Also key to my reporting was a review paper written by Marc Lipsitch of Harvard T.H. Chan School of Public Health, which was an excellent guide to the evidence on vaccines and antibiotic use. In my interview with him, Lipsitch emphasized that even viral vaccines can reduce antibiotic use and pointed me to research supporting that idea. (For example, by preventing flu, the flu vaccine reduces secondary bacterial infections and inappropriate antibiotic prescriptions.)
My editor, Blythe Terrel (now at Gimlet Media), smartly pushed me to develop the idea that explaining how vaccines reduce antibiotic use might encourage parents to vaccinate their kids, as my pediatrician source said happens in his practice. I spent a long time scouring vague PubMed searches for data on this but didn’t find much, except one study from Austria that found that people with more knowledge of the limitations of and problems with antibiotics were more likely to get a flu shot. I like to think that a vaccine hesitancy researcher might have read my piece and want to investigate this question further, because we could use more data on it!
One of my sources for this story, David Salisbury, associate fellow at the Chatham House Centre on Global Health Security in London, told me that for too long, there hasn’t been enough overlap between vaccines and antibiotic resistance in the research and policy worlds. Maybe journalists can learn from this as well. If you’re covering a vaccine story, is there a link to antibiotic use? And if you’re covering antibiotic use, is there a current vaccine or one in development worth mentioning?
Alice Callahan is an AHCJ member and freelance health writer with work published in FiveThirtyEight, The New York Times, The Washington Post, Everyday Health, and Slate. She’s the author of "The Science of Mom: A Research-Based Guide to Your Baby’s First Year" (Johns Hopkins University Press, 2015) and lives in Eugene, Ore.