Which of the following is not considered as one of the highly susceptible populations (HSPs)?

September 29, 2025 •

5 min read

According to the CDC, certain groups are at significantly higher risk for severe illness from infectious diseases due to weakened immune systems, age, or underlying health conditions. Understanding which of the following is not considered as one of the highly susceptible populations (HSPs) is just as important as knowing who is, allowing for more targeted protective measures in public health.

Quick Summary

Generally, a healthy, non-institutionalized adult is not considered one of the highly susceptible populations (HSPs), unlike young children, older adults, and those with weakened immune systems. A healthy high school student, for example, typically possesses a more robust immune response compared to individuals at the extremes of age or with specific health vulnerabilities.

Key Points

Identifying Non-HSPs: A healthy adult or a healthy teenager not in a high-risk setting is not considered a highly susceptible population (HSP).
Defining HSPs: Highly susceptible populations are individuals at increased risk for severe illness, including the very young, the elderly, pregnant women, and the immunocompromised.
Factors Affecting Susceptibility: Age, immune system status, living environment, and underlying health conditions are primary factors that increase susceptibility to disease.
Public Health Strategies: Public health efforts create specific protective measures for HSPs, such as stringent food safety protocols and targeted vaccination, while promoting general hygiene for the wider population.
Controlling for Environment: Individuals in group care settings like nursing homes and daycares are often categorized as HSPs due to their environment, which can increase exposure risk.
Protecting the Vulnerable: Understanding who is and isn't an HSP allows for more effective allocation of resources and communication of health risks to those most in need of protection.

Understanding Highly Susceptible Populations (HSPs)

Highly susceptible populations, or HSPs, are specific groups of people who are more likely than the general public to experience foodborne illness or other infectious diseases due to unique physiological or environmental factors. Their immune systems may be immature, weakened, or compromised, leaving them more vulnerable to pathogens that may only cause mild illness in healthy individuals. Official public health guidelines, particularly those related to food safety, often outline strict precautions when dealing with or serving these groups to prevent outbreaks.

Core Characteristics of Highly Susceptible Populations

The designation of an HSP is based on several key characteristics that increase the risk of severe disease. These can be related to age, a suppressed immune system, hormonal changes, or living situation. Identifying these characteristics is the first step in implementing appropriate protective measures, such as more stringent hygiene protocols in care facilities or tailored vaccine recommendations. For instance, an elderly person living in a nursing home is at higher risk not only due to age-related immunosenescence but also because of the close-quarters living environment.

The Answer to the Question

To answer the question, "Which of the following is not considered as one of the highly susceptible populations (HSPs)?" we must identify the group that does not fit the criteria of increased vulnerability. Based on public health definitions from sources like the CDC and state health departments, categories like preschool children, older adults, pregnant women, and the immunocompromised are clearly defined as HSPs. Therefore, a healthy individual who does not fall into these categories, such as a healthy high school student or a non-pregnant adult of childbearing age, is not considered part of the highly susceptible population. While they can still become ill, their general risk profile for severe outcomes is significantly lower than that of an HSP.

Key Groups Typically Classified as HSPs

Preschool-age children: Their immune systems are still developing, making them more vulnerable to infections. Childcare centers often implement specific rules to control infection spread. For instance, specific food preparation protocols are in place to reduce foodborne illness risks for children under nine in custodial care facilities.
Older adults: Individuals aged 65 and older experience a natural decline in immune function with age. Many also live with chronic diseases that increase their risk. Nursing homes and senior centers are considered facilities serving HSPs.
Immunocompromised individuals: This broad category includes people with conditions such as cancer, HIV/AIDS, or those taking immunosuppressive drugs, which leave their immune system weakened and unable to fight off infections effectively.
Pregnant women: Hormonal shifts and a naturally altered immune system during pregnancy put women at a higher risk of foodborne illnesses and other infections.
Patients in institutional care: Those residing in hospitals, nursing homes, assisted living, or kidney dialysis centers are considered HSPs due to their health status and concentrated living conditions.

Why Healthy Adults Are Generally Not HSPs

Healthy adults and teenagers possess a mature and fully functional immune system that is better equipped to combat common pathogens. They typically do not have the underlying health conditions or physiological vulnerabilities that define the other groups. This is not to say they are immune to illness, but rather that their risk of severe complications from infectious diseases is statistically lower. Public health messaging often addresses the general population differently than it does HSPs, with more targeted warnings and advice for at-risk groups.

Comparative Overview of Risk Factors


Risk Factor	Highly Susceptible Population (HSP)	Generally Healthy Adult	Reason for Difference
Immune System	Immature, senescent (aging), or compromised due to illness or medication.	Mature, robust, and fully functional.	An adult's immune system has developed full competency and memory against a range of pathogens.
Chronic Conditions	High prevalence of conditions like diabetes, kidney disease, or cancer.	Low prevalence; generally absent.	Underlying health issues can severely impact immune function and recovery time.
Environmental Exposure	Often live in close quarters in care facilities, increasing pathogen spread.	Varied and less concentrated exposure.	Congregated living settings (e.g., daycares, nursing homes) amplify transmission risk.
Risk of Complications	High risk of severe illness, hospitalization, or mortality.	Lower risk of severe outcomes from common infections.	Higher immune competence and overall health lead to better health outcomes.

Protective Strategies for Different Populations

Public health strategies must be tailored to the specific vulnerabilities of each population. While general hygiene practices like hand washing and covering coughs are important for everyone, the level of vigilance and the specific interventions required vary significantly.

For HSPs, particularly in institutional settings: Strict infection control protocols are mandatory. This includes meticulous cleaning and disinfection, careful food preparation, and potential restrictions on visitors during outbreaks. Healthcare workers receive specific training on these measures.
For the general healthy population: The focus is on encouraging good hygiene and vaccination to prevent illness and community spread. For example, staying home when sick protects both healthy individuals and, crucially, reduces the potential for disease to spread to more vulnerable community members.
Vaccination strategies: While many vaccines are universal, others are specifically targeted toward high-risk groups. For instance, certain vaccines may be particularly recommended for older adults or immunocompromised individuals to provide a stronger defense against specific pathogens.

The Importance of Public Health Awareness

Knowing the distinction between HSPs and the general population is crucial for effective public health management. It allows resources and protective measures to be allocated where they are most needed. Public health campaigns can deliver nuanced messages, providing heightened warnings and specific advice to at-risk individuals, while communicating general best practices to the wider community. This tiered approach is a cornerstone of effective disease prevention.

For more detailed information on people at increased risk for foodborne illness and other health issues, consult the Centers for Disease Control and Prevention at https://www.cdc.gov/food-safety/risk-factors/index.html.

Conclusion

While a variety of factors determine susceptibility to illness, highly susceptible populations are defined by specific characteristics such as extreme age, immunocompromised status, or pregnancy. In contrast, a healthy adult or teenager who does not have these underlying vulnerabilities is not typically included in the HSP classification. Understanding this distinction is vital for both personal health protection and broader public health policy, ensuring that the most vulnerable among us receive the highest level of protection.

Frequently Asked Questions

A highly susceptible population is a group at a higher-than-average risk for severe illness from infectious diseases. Examples include children under 5, adults over 65, pregnant women, and people with compromised immune systems.

Preschool-age children are considered highly susceptible because their immune systems are still developing. Their bodies are less capable of fighting off infections compared to older children and adults, and they are often in environments like daycare where germs spread easily.

As people age, their immune system function declines, a process called immunosenescence. Many older adults also have chronic health conditions that further weaken their ability to fight illness, making them more vulnerable to severe disease.

Yes, many underlying health conditions like diabetes, kidney disease, or HIV can suppress the immune system, making individuals more susceptible to infections and severe complications. This is a core factor in classifying an HSP.

Public health strategies for HSPs are often more stringent. For example, food service for HSPs has stricter safety requirements, and recommendations for infection control in care facilities are enhanced to prevent outbreaks.

A healthy high school student typically has a mature and robust immune system and generally lacks the chronic conditions or physiological changes that define HSPs. Their body is more capable of fighting off common illnesses effectively.

The primary difference lies in the level of risk for severe illness. While the general public can get sick, a susceptible population faces a higher likelihood of experiencing more serious health complications, hospitalization, or mortality from the same pathogen.