Americans are bombarded with information about the harm and risk of e-cigarette use—much of which is confusing or conflicting. This is because the e-cigarette debate has become fractured and polarized, resulting in mixed messages from public health organizations, media and government agencies. In light of this, if adults are going to be able to make informed decision about e-cigarettes, it is imperative that public health messaging must accurately portray not only absolute but also relative harm.

In a recently released study, Jidong Huang et al. investigate how the perceived risk from using e-cigarettes, relative to combustible cigarettes, has changed among adults in the United States. In doing so, the authors evaluated overall trends and assessed changes in perception of harm based on the participant’s history of smoking and vaping.

Using Health Information Trends Survey (HINTS) data, the researchers found that in 2012, about 50.1 percent of adults surveyed correctly believed e-cigarettes were less harmful than combustible cigarettes, 46.4 percent perceived the two products to be equally harmful and 2.8 percent believed e-cigarettes were more harmful.

However, from 2012 on, the authors noted significant changes in perception. For example, by 2014, the proportion of adults who perceived e-cigarettes and combustible cigarettes to be equally harmful had surpassed the proportion that perceived them as less harmful. Moreover, the proportion who believed e-cigarettes were more harmful than combustible cigarettes was beginning to increase. By 2017 (the study’s most recent year of data), only 34.5 percent of adults perceived e-cigarettes as less harmful than combustible cigarettes, while 9.9 (roughly a 7 percent increase from 2012) perceived them to be more harmful. The percentage of adults who perceived the products to be equally harmful also increased to a high of 55.6 percent.

Because the HINTS survey upon which their dataset relied did not provide an option for participants who had no clear perception of the harm of e-cigarettes relative to combustible ones, Huang et al. also analyzed an additional dataset that did offer this response. While data from the Tobacco Products and Risk Perception Survey (TPRPS) and the HINTS data showed similar trends in change of perception, the TPRPS data also showed a sharp decline in the proportion of adults who reported not knowing how the relative harms of these two tobacco products compared. This means that, over time, more adults have formed opinions about the relative harm of e-cigarettes, but this increased awareness is of little benefit if the information upon which they base their opinions is incorrect.

In late 2013, as e-cigarette use became more mainstream, health organizations began to fear that tobacco use would become “renormalized.” To counter this potential phenomenon, public health messaging pivoted to focus on the harms and risks of vaping and specifically to change public perception of e-cigarettes and their potential for harm. Concerned about non-smokers who may be enticed to begin vaping, the messaging centered on the absolute risk of e-cigarettes or, in other words, the independent risks associated with e-cigarette use. However, in focusing their messaging on discouraging non-smokers from picking up the habit, public health officials essentially neglected the most relevant information for those who already smoke, which is that relative to combustible cigarettes, e-cigarettes are a far less harmful alternative.

The results of such incomplete information were on display in Huang et al.’s study, which showed that the highest proportion of adults who believed e-cigarettes are more harmful than combustible cigarettes were current smokers. This finding was consistent in both datasets, with 14.2 percent of smokers holding this perception in the HINTS sample and 5.5 percent in the TPRPS. The TPRPS dataset also showed that a higher proportion of “smokers” than “never smokers” did not know the relative harm of e-cigarettes, which is estimated to be 95 percent lower than the harm associated with combustible ones. This is particularly concerning given that it is smokers who have the most to gain from understanding the relative harm of using e-cigarettes rather than combustible ones. And, if they are misinformed by only hearing messages about absolute harm, they will be far less likely to switch to the safer product.

Sadly, perceptions held by dual-users (people who use e-cigarettes and combustible cigarettes) and current e-cigarette users were similar to those of smokers. Although current e-cigarette users were most likely (at 61.6 percent in 2017) to report that they believed e-cigarettes less harmful than combustible ones, a higher percentage of this group, compared to those who had never smoked, also reported that e-cigarettes were more harmful than combustible cigarettes. Worse, in 2017, 6.1 percent of dual users perceived e-cigarettes as more harmful than combustible cigarettes, which is higher than any other group. This is concerning because those in the dual-use and current e-cigarette groups have already made difficult strides to change their behavior for the better, and these misperceptions based on incomplete or inaccurate information may place them at risk of switching back to combustible cigarettes—to the detriment of their health.

In light of all of this, the findings of Huang et al. provide valuable information for designing tobacco harm reduction messaging. If we are to reduce smoking-related illness and mortality, it is of key importance that the public has the kind of complete and accurate information that allows them to make fully informed choices. It is therefore the obligation of health professionals to provide all relevant information about known harm, both relative and absolute. Including both measures provides necessary information to all groups. While absolute-harm messaging can deter non-smokers from initiating e-cigarette use, relative-harm messaging can inform current smokers that switching to e-cigarettes can drastically reduce the harms caused by tobacco consumption.