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Immunization Science

Vaccine Safety Concerns and Immunization Status

The article

Underimmunization Among Children: Effects of Vaccine Safety Concerns on Immunization Status. Gust DA, Strine TW, Maurice E, Smith P, Yusuf H, Wilkinson M, Battaglia M, Wright R, and Schwartz B. Pediatrics 2004;114(1):e16-e22

Explanatory note: Immunizations have prevented vaccine-preventable diseases so effectively that fear of these diseases has diminished. Loss of fear of most of these infections is inappropriate, however, as the risks for exposure persists. In addition to this phenomenon, concerns about vaccine safety have increased, largely fueled by misinformation about vaccine safety. For example, some have concerns about autism and measles-mumps-rubella (MMR) vaccine, multiple sclerosis and hepatitis B vaccine, and sudden infant death syndrome and diphtheria-tetanus-pertussis (DTP) vaccine despite the fact that current scientific evidence does not support associations between these vaccines and conditions.

The question

How do the vaccine safety-related attitudes, beliefs, and behaviors of parents whose children are underimmunized differ from those of parents whose children are fully immunized?

The study

The researchers interviewed 2,315 parents who had 3 to 9 months previously participated in the National Immunization Survey of 19-35 months old children. This is an annual telephone survey conducted by the Centers for Disease Control and Prevention.

Respondents were divided into two groups: cases and controls. The cases children were incompletely immunized against 2 or more of 3 vaccines: DTP/DTaP, hepatitis B, and measles. Control children were fully immunized with these same vaccines. The researchers felt that this selection process (incomplete immunization for at least 2 high-profile vaccines) would increase the likelihood that they were studying parents who had made a purposeful decision for their children to not receive the vaccines.

This study collected data on demographic characteristics and attitudes, beliefs, and behaviors of the parents concerning immunizations. The researchers then analyzed the data to determine the importance of parent's negative attitudes, beliefs and behavior toward immunizations upon the likelihood of not vaccinating their children.

The findings

The families of underimmunized children more commonly had lower income, visited more healthcare providers, moved more frequently, and had more children than families of fully immunized children.

This study found that more parents whose children were underimmunized (7.3%) versus fully immunized (1.4%) reported that they would not want a new infant to receive all recommended immunizations.

Scoring vaccines as somewhat or not safe versus safe also was more prevalent among parents whose children were underimmunized (20.2%) than parents whose children were fully immunized (9.8%).

Also, more parents whose children were underimmunized (11.3%) than fully immunized (4.2%) asked the child's medical provider not to give the child a vaccine for reasons other than illness.

However, some parents of fully immunized children also expressed vaccine safety concerns.

The relevance/bottom line

Vaccine safety concerns have contributed substantially to underimmunization in the United States. Although in this study concerns were more commonly expressed by parents of underimmunized children, many parents of fully immunized children also expressed similar attitudes and beliefs.

NNii's comments

Telephone surveys have great limitations and in this case the researchers were only able to reach about half of the cases. Attitudes, beliefs and behaviors differ across socioeconomic and ethnic groups. Nevertheless, the fact that so many parents (both immunized and underimmunized) expressed concerns about vaccine safety suggests that:

• Misinformation about vaccine safety has confused many parents. 
• These types of attitudes pose a potential risk to high immunization coverage levels (which are needed to prevent the spread of vaccine preventable diseases).