prophylaxis

Prophylaxis refers to measures taken to prevent disease, injury, or complications rather than to treat an existing condition. In medicine, prophylaxis is commonly described along a spectrum from primary prophylaxis (preventing disease in at-risk individuals) to secondary prophylaxis (preventing recurrence or progression after a first episode) and, in some frameworks, tertiary prophylaxis (preventing complications once disease has begun).

Prophylaxis can be pharmacologic (chemoprophylaxis), immunologic (immunoprophylaxis), or nonpharmacologic. Pharmacologic prophylaxis uses medications such as antibiotics, antimalarials, or antivirals to reduce the chance of infection. Immunoprophylaxis includes vaccines and immune globulins that provide active or passive protection. Nonpharmacologic measures include behavioral changes and mechanical methods such as hand hygiene, barrier precautions, personal protective equipment, and avoidance of known exposures. In clinical settings, prophylaxis is often procedural, such as antibiotic prophylaxis before certain surgeries or dental work to prevent surgical site infection or endocarditis.

Common examples include malaria chemoprophylaxis for travelers; antibiotic prophylaxis before dental procedures for patients with certain heart conditions; post-exposure prophylaxis (PEP) for HIV after potential exposure, or pre-exposure prophylaxis (PrEP) for people at ongoing risk; and routine immunization to prevent diseases such as influenza or hepatitis B. Tetanus and other injury-prophylaxis regimens are also standard components of prophylaxis in wound care.

Implementation of prophylaxis requires assessment of disease risk, exposure likelihood, patient factors, and potential adverse effects. Guidelines from health authorities help balance benefits and harms and address antimicrobial resistance and cost. Prophylaxis is not a substitute for public health measures and sanitation, and its use should be targeted and evidence-based.