The Economics of Antibiotics and Negative Externalities

The Incident at the White House: * Date: June 1924. * Victim: Calvin Coolidge junior, the son of United States President Calvin Coolidge. * Cause of Illness: While playing lawn tennis outside the White House, Calvin junior developed a simple blister on his right foot. * Medical Progression: The blister led to a staph infection, which subsequently developed into sepsis. * Outcome: Calvin junior died one week after the injury occurred.
The State of Medicine in the 1920s: * Despite being the son of the President, there was no available medicine to save him. * Deaths from infection were extremely common. * Minor wounds frequently escalated into life-or-death situations.
The Medical Breakthrough: * Discovery: Penicillin was discovered in 1928, just four years after the death of Calvin junior. * Impact: This first antibiotic revolutionized medicine, transforming fatal bacterial infections into easily curable ailments.

The Superbug Problem: The "miracle" of antibiotics is currently under threat from superbugs—bacteria that have become resistant to antibiotic treatment.
The Evolutionary Process of Resistance: * No antibiotic is $100\%$ effective. * When an antibiotic is used, it kills most bacteria, but the stronger, mutated bacteria survive. * These surviving bacteria flourish and reproduce, eventually rendering the specific antibiotic ineffective against new generations of bacteria. * As new antibiotics are developed, this evolutionary cycle repeats, leading to the emergence of multi-drug resistant superbugs.
The Fundamental Resource Problem: Antibiotic users receive the full benefit of the medication without bearing the total cost. Every time an antibiotic is used, it causes a small increase in bacterial resistance, which eventually results in less effective medicine for everyone else in society.

The Model of Trade: * Buyers: Represented by the Demand curve. * Sellers: Represented by the Supply curve. * Mutually Beneficial Exchange: A trade occurs when the buyer values the good more than the market price, and the seller can produce it for less than the market price. Both benefit from the transaction. * Surplus: Markets maximize "gains from trade," which includes Consumer Surplus and Producer Surplus.
Internalities vs. Externalities: * Buyers and Sellers: The primary participants in the market process. * Bystanders: Third parties who are neither buying nor selling but are nonetheless affected by the purchase and use of the product. * Externalities: Effects on bystanders that are not accounted for by the buyers and sellers. These can be positive (benefits) or negative (costs).

The Graphical Framework: * Horizontal Axis ( $x$ -axis): Quantity ( $Q$ ) of antibiotics. * Vertical Axis ( $y$ -axis): Prices ( $P$ ) and Costs ( $C$ ).
Cost Definitions: * Private Cost: The cost of producing the antibiotic paid by the supplier (represented by the standard Supply curve). * External Cost: The cost imposed on bystanders, specifically the cost of increased bacterial resistance. * Social Cost: The total cost to everyone in society, defined as the sum of Private Cost and External Cost ( $Social \, Cost = Private \, Cost + External \, Cost$ ).
Curves and Relationships: * The Social Cost Curve sits vertically above the private supply curve. * The vertical distance between the Supply curve and the Social Cost curve represents the External Cost.

Market Equilibrium vs. Social Optimum: * Market Equilibrium ( $Q_{market}$ ): Found where Demand intersects Supply (Private Cost). This point maximizes consumer and producer surplus but ignores bystanders. * Socially Efficient Quantity ( $Q_{social}$ ): Found where the Social Cost curve intersects the Demand curve. This point maximizes Social Surplus (Consumer Surplus + Producer Surplus + Bystander Surplus).
The Problem of Overuse: * The market equilibrium quantity ( $Q_{market}$ ) is higher than the socially efficient quantity ( $Q_{social}$ ). * This discrepancy represents the over-consumption and over-production of antibiotics.
Deadweight Loss Analysis: * For the units produced between $Q_{social}$ and $Q_{market}$ , the Social Cost is greater than the private value (the height of the Demand curve). * The area between the Social Cost curve and the Demand curve from $Q_{social}$ to $Q_{market}$ is the Deadweight Loss. * Producing these units makes society worse off because the cost to everyone exceeds the benefit to the individual user.

High-Value vs. Low-Value Uses: * If every antibiotic use was for a high-value purpose (e.g., saving a life), the rise of resistance might be unavoidable but justified. * However, antibiotics are often used for low-value purposes, such as patients taking them when they are not medically necessary.
Price Inaccuracy: * The market price of antibiotics is too low because it does not include the cost of bacterial resistance (the external cost). * This low price incentivizes consumption in scenarios where the social cost exceeds the individual value.
The Goal of Intervention: * The optimal quantity of antibiotic use is almost never zero. * The goal is to maintain access for high-value users (e.g., those with dangerous infections) while discouraging low-value uses through higher prices or other regulatory mechanisms.
Summary of Social Surplus: * Free markets maximize personal gains ( $Consumer \, Surplus + Producer \, Surplus$ ). * When external costs are high, the free market fails to maximize total Social Surplus because it ignores the costs to bystanders.