February 2, 2017

Vast Majority of Americans Say Benefits of Childhood Vaccines Outweigh Risks

4. Public trust in medical scientists and their research on childhood vaccines

Public trust in information from medical scientists about the health effects of the measles, mumps and rubella vaccine is more positive than negative. And more Americans trust information about this topic from medical scientists than from pharmaceutical industry leaders, people from holistic or alternative health groups, the news media or elected officials.

Most Americans see broad consensus among medical scientists that the MMR vaccine is safe for healthy children. Public perceptions of medical scientists’ understanding about the vaccine also tilt positive. Nearly half of Americans think medical scientists understand the health risks and benefits of such vaccines very well, while a nearly equal portion rate their understanding as “fairly well”; only a small minority says medical scientists do not understand the health effects of the MMR vaccine at all or not too much.

About half or more Americans have a positive view of medical research about vaccine safety, saying that the best interests of children’s health and the best available scientific evidence influence research most of the time. By comparison, fewer people say that researchers’ desire to help connected industries or advance their careers influence medical research on vaccines most of the time.

There is considerable variation in public views about medical scientists, however. People with high knowledge about science, based on an index of nine general science questions, have more positive views of medical scientists and their research on vaccines than do those with low science knowledge. There is a similar, though less pronounced, tendency for people who care more deeply about childhood vaccine issues to see medical scientists in a more positive light.

There are modest differences in trust by generation, with younger adults a bit more skeptical than older generations about medical scientists and their research. Statistical models show that seniors, ages 65 and older, are consistently more likely than those ages 18 to 29 to hold positive views of medical scientists and their research on childhood vaccines, when controlling for demographic, education and political factors.

Overall, though, a strong majority of Americans support a role for medical scientists in policy decisions related to childhood vaccines.

Roughly half of Americans say almost all medical scientists are in agreement that vaccines are safe and that medical scientists understand the effects of childhood vaccines very well

Some 55% of the general public says that “almost all” medical scientists see childhood vaccines for measles, mumps and rubella as safe for healthy children. An additional 28% say more than half of medical scientists are in agreement on this, while 15% say that about half or fewer medical scientists think that childhood vaccines are safe for healthy children.

A number of medical and scientific associations have issued statements about the safety of childhood vaccines, although most do not characterize the beliefs of medical scientists. A consensus study from National Academies of Sciences, Engineering and Medicine in 2011 reviewed the evidence for adverse effects connected with all vaccines recommended by the Centers for Disease Control and Prevention for routine administration in children including the MMR.13 It concluded “the MMR vaccine is linked to a disease called measles inclusion body encephalitis, which in very rare cases can affect people whose immune systems are compromised” and rejected a relationship between the MMR vaccine and autism.

A 2014 survey by the Pew Research Center found that 86% of U.S.-based members of the American Association for the Advancement of Science (AAAS) (and 87% of members who are working Ph.D. biomedical scientists) said that childhood vaccines such as the MMR and polio vaccines should be required. Just 13% said that the decision about whether to get vaccinated should be left to parents.

Nearly half of Americans (47%) think medical scientists understand the health risks and benefits of childhood vaccines very well, and 43% say medical scientists understand the risks and benefits fairly well. Just one-in-ten (10%) Americans think medical scientists understand the health risks and benefits not too well or not at all well.

Roughly half of U.S. adults trust medical scientists a lot for information about the effects of vaccines; trust in information from other groups is much lower

Some 55% of Americans say that they trust medical scientists a lot to give full and accurate information about the risks and benefits of childhood vaccines. An additional 35% trust medical scientists at least some, and just 9% say they do not trust information from medical scientists about the risks and benefits at all or not too much.

Trust in information from other groups is much lower, by comparison. Just 13% of Americans trust information from pharmaceutical industry leaders a lot. At the same time, just 9% of Americans trust information on the effects of the MMR vaccine a lot from holistic or alternative health groups.

Few people have a lot of trust in information from either the news media (8%) or elected officials (6%) about the health effects of the MMR vaccine; fully 56% of Americans say they do not trust media information on this at all or not too much, and 67% say the same about information from elected officials.

Roughly half of Americans say medical research is influenced by the best available scientific evidence and concern for children’s health most of the time

Many Americans have a positive view of medical research about vaccine safety; roughly half say such research reflects the best interests of children’s health (55%) and the best available scientific evidence (52%) most of time.

Smaller shares of the public say such research is influenced by medical scientists’ desire to help their industries (27%), their desire to advance their careers (27%) or their own political leanings (18%) most of the time.

Patterns in public trust of medical scientists and vaccine research

Those with more knowledge about science, in general, are especially likely to see consensus among medical scientists about the safety of the measles, mumps and rubella vaccine and to trust information from medical scientists about the effects of the MMR vaccine.

Eight-in-ten adults with high science knowledge (80%) say that almost all medical scientists consider the MMR vaccine to be safe. In contrast, 43% of those with low science knowledge think almost all medical scientists agree on this. Similarly, those with high science knowledge are more likely that those with low science knowledge to think medical scientists understand the health risks and benefits of the MMR vaccine very well (64% vs. 37%).

People with high science knowledge are more trusting of information from medical scientists. Some 73% of this group says they trust medical scientists a lot to give full and accurate information about the health effects of the MMR vaccine, compared with 40% of those with low science knowledge.

People high in science knowledge are more inclined to see medical research on vaccines in a positive light. Seven-in-ten (70%) of them say medical research is influenced by concern for the best interests of children’s health most of the time, compared with 43% of those low in science knowledge. Fully 72% of those high in science knowledge say childhood vaccine research is influenced by the best available scientific evidence most of the time, compared with 34% of those low in science knowledge.

People’s science knowledge levels are closely associated with education. There are similar differences across educational groups in views about medical scientists and their research on childhood vaccines.

And, there is similar tendency, though a bit less pronounced, for those with a deep concern about childhood vaccine issues to express more trust in medical scientists and their research compared with those who do not care at all or not too much about these issues.

There are differences by age in views about medical scientists and their research. Younger adults, ages 18 to 29, are a bit less likely than older age groups to say that medical scientists understand the health effects of childhood vaccines very well and to perceive strong consensus among medical scientists about the safety of the MMR vaccine.

Compared with older adults, those ages 18 to 29 are somewhat less likely to think the best available evidence influences research findings on childhood vaccines most of the time.

Trust in information from medical scientists is roughly the same across age groups, though a somewhat larger share of adults ages 18 to 29 do not trust information about the effects of vaccines from medical scientists at all or not too much.

There are modest differences in views of medical scientists connected with people’s use of alternative and conventional medicine. People who have used alternative medicine instead of conventional treatment are a bit less likely to see medical scientists as understanding the health risks and benefits of the MMR vaccine very well (38% compared with 47% of those who have never tried alternative medicine).

People who have used alternative medicine instead of traditional medicine are less trusting of information from medical scientists (43% trust medical scientists a lot vs. 59% of those who have never used alternative medicine). But even among those who have tried alternative medicine, few say they trust information from people in holistic or alternative health groups a lot to give full and accurate information about the health effects of the MMR vaccine. And views about the influences on medical research related to childhood vaccines are about the same or only slightly different depending on one’s past use of alternative medicine.

Similarly, the 8% of Americans who say they never take over-the-counter medications for cold and flu symptoms are less likely than other Americans to believe that medical scientists understand the risks and benefits of the MMR vaccine very well (33% do so compared with 48% of those who take such medications right away). Those who never take over-the-counter medications are also less likely to trust information from medical scientists; some 34% of this group does not trust information from medical scientists at all or not too much, compared with 5% of those who take these medications right away. They are about equally likely to think the best available evidence influences medical research most of the time (44% vs. 49% of those who take these medications right away). However, differences in views about medical scientists and their research by use of over-the-counter medications or alternative medicine have no more than modest effects in statistical models when demographic and other factors are statistically controlled.

Overall, statistical models show that people with higher levels of science knowledge and greater concern about childhood vaccine issues are consistently associated with more positive views of medical scientists, even when statistically controlling for demographics, education and political factors. In addition, adults ages 65 and older are consistently more likely than younger adults to hold positive views of medical scientists across this set of measures in statistical models controlling for demographic and other factors. For details, see Appendix A.

Views about medical scientists and their research on childhood vaccines are roughly the same across racial and ethnic groups, though beliefs about the risks and benefits of vaccines vary across these groups, as shown in Chapter 3.

There are modest religious group differences in public trust in medical scientists on some of these measures. For example, white evangelical Protestants are less likely to trust information from medical scientists about the effects of the MMR vaccine compared with white mainline Protestants, Catholics and the religiously unaffiliated. White evangelical Protestants rate medical scientists’ understanding of the risks and benefits of the MMR vaccine lower than do either white Catholics or the religiously unaffiliated. And, white evangelical Protestants are less likely than either white Catholics or the religiously unaffiliated to think medical research on childhood vaccines is influenced by the best available scientific evidence most of the time. A separate series of statistical models, not shown in this report, find differences by religious affiliation on these three judgments are statistically significant even when controlling for demographics, education and political factors.

Most Americans support a major role for medical scientists in policymaking on childhood vaccine issues

Some 73% of U.S. adults say medical scientists should play a major role in policymaking decisions related to childhood vaccines. A smaller share, 47%, says the general public should play a major role in policy decisions about childhood vaccines.

A minority of Americans say pharmaceutical industry leaders (27%), health insurance company leaders (26%) and elected officials (25%) should have a major role in policy decisions on childhood vaccine issues.

  1. See Report brief for “Adverse Effects of Vaccines: Evidence and Causality” 2011. National Academies of Sciences, Engineering and Medicine, August. Also see the summary from the Centers for Disease Control and Prevention on vaccine safety.