Final answer:
The exact percentage of hospitals that have not had contact with a patient in 18 months or longer cannot be determined from the question as it lacks specific data. Generally, infectious disease control and hospital statistics would be relevant subjects for College-level health studies in understanding hospital-patient contact rates.
Step-by-step explanation:
The question does not provide sufficient information to accurately determine what percentage of hospitals have not had contact with a patient in 18 months or longer. Information regarding hospital-patient contact frequencies is typically gathered from healthcare studies or institutional reports rather than general knowledge or specific subjects like Mathematics or Health. However, to address a hypothetical situation where there is a study with relevant data, analyzing this data would most likely fall under the subject of Health at a College level, given the complexity and specificity of healthcare statistics.
Infectious Disease Control in hospitals is a vital aspect of healthcare. Studies like the cohort study mentioned can help understand the effectiveness of procedures like administering prophylactic antibiotics to reduce the risk of hospital-acquired infections (HAI). Such measures are crucial, especially when considering that a significant percentage of invasive MRSA infections are healthcare-associated. Healthcare statistics and research studies are fundamentally important for patient safety and hospital management.