There are a few tried and true approaches to creating a flu-shot campaign. One is the “big sad numbers” approach, with official flu-death numbers from the previous year. Or there’s the personal story of an otherwise healthy individual who unexpectedly died from the flu. Another option is the appeal to altruism.

Depending on age, gender, and even geographical region, these messages can resonate differently. Data science firm Civis Analytics looked at which has the highest rate of success and found that the altruism message did best overall, increasing a consumer’s intent to vaccinate by 8% from the baseline number.

“Often in public health, the thought is that if you use a specific story and talk about a specific person, that’s the most impactful thing for public audiences,” said Crystal Son, healthcare analytics lead at Civis Analytics. “But the data we found says that’s not the case, the personal story is much less effective.”

Altruism beat the other two messages across every gender, age, and regional group by several points, but some messages did better with certain demographics.

Men, for example, responded to the “big sad numbers” approach, but that message faced a backlash among women. The personal story message was slightly more effective among women than men.

The study measured backlash as a decrease in the baseline intent to vaccinate, or the percentage of participants who said they would get a flu shot this year, which was about 38%. 

The study polled 2,400 adults in October. Each respondent was assigned to one message or the control group.

The big sad numbers approach has more backlash risk than the other two messages. It had backlash potential across all age groups, U.S. regions, and demographics, and it only raised the intent to vaccine by 2%.

Across regions, altruism performed best. In the Northeast, the difference between the messages was even more stark, with altruism boosting the intent to vaccinate by 9% and the numbers and personal story coming far behind at 2% and 3%, respectively. The personal story message did best in the South.

Among people who said they didn’t get a flu shot last year, the altruism message did even better. It increased their intent to vaccinate by 10%, two points higher than those who did get a flu shot the previous year.

“If you said you didn’t get a flu shot last year, that’s a group you really want to move the needle on,” Son said. “The altruism [message] was the most impactful. We were a little surprised by this because we thought this was the staunch ‘I don’t vaccinate’ group, but it shows there’s some potential for persuading these folks as well.”