Which best explains why the Vaccine Adverse Event Reporting System (VAERS) was originally legislated? (Select all that apply.)

Correct Answer: C

Rationale: No drug is perfectly safe or effective. The VAERS allows for the monitoring of actual and potential vaccine-related problems. Changes are made on the basis of the collected data. For example, whole cell pertussis vaccine was changed to an acellular pertussis vaccine because of adverse side effects. To monitor actual and potential vaccine-related problems, health care providers must report specific postvaccination 'adverse events' to the VAERS. The National Vaccine Injury Compensation Program reviews all VAERS reports and provides assistance for individuals and families who experience a vaccine-related injury, including disability and death. The VAERS does not provide education to health care professionals on proper vaccine administration or conduct media campaigns to help convince parents to bring their children in to receive appropriate immunizations. Vaccines can produce a variety of responses, both positive and negative. Thus, side effects can occur in healthy people. [Note: E is unlisted in the options but implied as 'To monitor actual and potential vaccine-related problems' per the rationale.]

Correct Answer: B

Rationale: Nutritional deficiencies are included under agent factors. Although too much of an agent can cause disease (such as obesity related to diabetes), so can too little of an agent. Relative risk indicates the extent of excess risk incurred by exposure relative to nonexposure. Host factors are intrinsic factors and describe one's susceptibility or response influence to the exposure to the agent, such as genetics, age, sex, ethnicity, and human behavior. Environment factors are extrinsic factors and they influence the existence of the agent, exposure, or susceptibility to the agent such as physical environment, biological environment, and socioeconomic environment.

Correct Answer: D

Rationale: Causation assessment (e.g., Bradford Hill criteria) includes strength of association (A), temporality (B), and reversibility (C), among others. All are considered (D) to evaluate if an exposure causes an outcome (e.g., smoking cessation reducing lung cancer risk supports causality).

Correct Answer: A

Rationale: Incubation period (A) is from exposure to symptom onset (e.g., measles: 10–14 days). B, C, and D describe other intervals.

Correct Answer: A

Rationale: Passive surveillance (A) relies on routine reporting (e.g., by providers). B, C, and D are active methods requiring outreach.