Which primary prevention strategy will the nurse include in a community program on the prevention of hepatitis C?

Correct Answer: D

Rationale: The correct answer is D because sharing needles or other equipment contaminated with blood is a significant risk factor for contracting hepatitis C. By instructing individuals to avoid sharing such equipment, the nurse is targeting a key mode of transmission for the virus. This primary prevention strategy directly addresses the root cause of hepatitis C transmission in high-risk populations. Choice A is incorrect because while screening for hepatitis C is important, it is not a primary prevention strategy. Choice B is incorrect as handwashing is essential for preventing the spread of infections like hepatitis A and E, not hepatitis C. Choice C is incorrect because immunizations against other viral hepatitis infections do not protect against hepatitis C specifically. In summary, advising individuals to avoid sharing needles or equipment contaminated with blood is the most effective primary prevention strategy for hepatitis C compared to the other choices provided.

Correct Answer: D

Rationale: Probably one of the most profound failures in infectious disease control in the United States and elsewhere is that the successes are not equally distributed in the general population. Infectious diseases continue to be differentially distributed by income and ethnic groups, and the poor and minorities continue to experience the greater burden. There continues to be an increase in vector-borne infections, but there has been a decrease in food-borne and waterborne infections. There is concern that deadly pathogens will be weaponized by terrorists.

Correct Answer: D

Rationale: Herd immunity is a state in which those not immune to an infectious agent will be protected if a certain proportion (generally considered to be $80 \%$ ) of the population has been vaccinated or is otherwise immune. Because most children in the school are immune, it will be difficult for the chickenpox to spread.

Correct Answer: C

Rationale: The researchers concluded that ecosocial or contextual conditions strongly enhance sexually transmitted infection risk by increasing sexual risk behaviors and likelihood of exposure to infection. Thus, the environment has been determined to be a more important variable in sexually transmitted infections than the pathogenesis, susceptibility, and the amount of sex education provided.

Correct Answer: B

Rationale: The positive predictive value is affected by what proportion of the tested population has the problem. To increase the positive predictive value, screen populations most at risk for the problem. Testing a large population at once, using a very sensitive or very specific screening test would not increase the positive predictive value of a screening test.