Question

Vaccines don't provide immunity from disease for some people. But if most people get vaccinated against a disease, such as measles, then the population achieves "herd immunity," which means that there are so few cases of the disease that even people for whom vaccinations are ineffective are unlikely to contract the disease. An article in the Economist argued that "herd immunity is a classic public good." a. Do you agree with this statement? b. The same article argued that there is an incentive to "free ride' off the contributions of others" by not getting vaccinated. What does the author mean by "free ride"? If the author is correct, what will be the effect of this free riding? c. Given your answer to part (b), why do most people vaccinate their children against childhood diseases, and why do many adults get vaccinated against influenza?

Short answer

a. Yes, herd immunity is indeed a public good as it is non-excludable and benefits all, including those who cannot get vaccinated. b. 'Free riding' refers to the practice of benefiting from the herd immunity without getting vaccinated, risking the overall immunity if practiced widely. c. People get vaccinated because of various reasons including social responsibility, trust in medical science, and the understanding of maintaining herd immunity.

Step-by-step solution

Understanding Herd Immunity as a Public Good

Herd immunity is considered a public good because it benefits everyone in the community, including those who cannot or choose not to get vaccinated. Public goods are non-excludable, meaning that even if an individual does not contribute (in this case, by getting vaccinated), they cannot be excluded from the benefits that the public good provides (i.e., herd immunity). Often, public goods are also non-rivalrous, indicating that one person's use of the good does not reduce its availability to others.

Discussing 'Free Riding' in Vaccination Context

The term 'free ride' refers to when an individual receives a benefit (such as protection from disease via herd immunity) without contributing to the cost (getting vaccinated). The author suggests that because of the public good nature of vaccines, there is an incentive for individuals to 'free ride', or benefit from the herd immunity provided by others' vaccinations without getting vaccinated themselves. If this occurs widely, it could lead to a decrease in the overall vaccination rate, threatening the overall herd immunity of the population.

Understanding Motivations for Vaccination

The reasons why most people vaccinate their children and get vaccinated themselves can be multifaceted. This can involve a sense of social responsibility, the desire to protect one's own health and that of others, trust in medical science, to avoid legal or societal consequences, and more. Despite the 'free ride' phenomenon, many understand that high vaccination rates are important in maintaining herd immunity and protecting those who cannot receive vaccines due to medical reasons.

Key concepts

Public Good

Herd immunity is what we call a public good. But what exactly does that mean? Public goods are generally characterized by two main traits:

• Firstly, they are non-excludable. This means once the public good is provided, you cannot prevent anyone from enjoying its benefits, even if they do not contribute to its production.
• Secondly, they are non-rivalrous. One person's enjoyment of the good does not reduce its availability to others.

In the context of herd immunity, the immunity provided to a community by widespread vaccination is available to all, regardless of one's vaccination status. Even those without a functioning or effective vaccine benefit from others being vaccinated - they are less likely to encounter the disease.
This makes herd immunity a quintessential public good, as it spreads protection to both those who contribute to it by getting vaccinated and those who do not.

Free Riding

'Free riding' is a term used to describe individuals who benefit from resources or services without paying for the cost of the benefit. In the sphere of vaccinations, free riders are those who opt to not get vaccinated but still benefit from the lowered risk of disease, thanks to the vaccinated populace.

When a significant number of people decide to free ride, the level of immunization can drop below the threshold necessary to maintain herd immunity. This could lead to the resurgence of diseases, putting the entire community at risk. Hence, while it might seem advantageous for some to rely on others to maintain herd immunity, it carries the risk of diminishing its effectiveness, endangering the broader public's health.

Vaccination Incentives

People often vaccinate despite the temptation to free ride because they have strong incentives to do so. These incentives arise from various motivations:

• Protecting personal health: Vaccines greatly reduce the risk of contracting diseases and related complications.
• Social responsibility: Many recognize the importance of protecting those who can't be vaccinated due to age or medical conditions.
• Legal and societal pressures: Schools and workplaces may require vaccinations for entry, encouraging compliance.
• Trust in science: Trust in health professionals and scientific research supports uptake of vaccines as a safe preventative measure.

Hence, multiple factors contribute to the decision to vaccinate, reinforcing societal efforts to maintain high vaccination rates and strong herd immunity.

Non-excludability

Non-excludability in the context of public goods refers to the inability to exclude individuals from enjoying the benefits of the good, regardless of their contribution level. Herd immunity is non-excludable, as individuals in a community benefit from the protective effects of widespread vaccination, whether they themselves are vaccinated or not.

For instance, consider a neighborhood where most children are vaccinated against measles. Even unvaccinated children are less likely to catch the disease, simply because the disease has fewer chances to spread. This demonstrates how non-excludability works in practice. The benefits of herd immunity thus extend to everyone, underscoring why it's considered a classic example of a public good.