Our immune systems help us fight off disease, but certain health conditions and medications can weaken our immune systems. People whose immune systems don’t work as well as they should are considered immunocompromised.

Read on to learn more about how the immune system works, what causes people to be immunocompromised, and how we can protect ourselves and the immunocompromised people around us from illness.

What is the immune system?

The immune system is a network of cells, organs, and chemicals that helps our bodies fight off infections caused by invaders, such as bacteria, viruses, fungi, and parasites.

Some important parts of the immune system include: 

• White blood cells, which attack and kill germs that don’t belong inside our bodies. 
• Lymph nodes, which help our bodies filter out germs. 
• Antibodies, which help our bodies recognize invaders.
• Cytokines, which tell our immune cells what to do.

What causes people to be immunocompromised?

Some health conditions and medications can prevent our immune systems from functioning optimally, which makes us more vulnerable to infection. Health conditions that compromise the immune system fall into two categories: primary immunodeficiency and secondary immunodeficiency.

Primary immunodeficiency

People with primary immunodeficiency are born with genetic mutations that prevent their immune systems from functioning as they should. There are hundreds of types of primary immunodeficiencies. Since these mutations affect the immune system to varying degrees, some people may experience symptoms and get diagnosed early in life, while others may not know they’re immunocompromised until adulthood.

Secondary immunodeficiency

Secondary immunodeficiency happens later in life due to an infection like HIV, which weakens the immune system over time, or certain types of cancer, which prevent the body from producing enough white blood cells to adequately fight off infection. Studies have also shown that getting infected with COVID-19 may cause immunodeficiency by reducing our production of “killer T-cells,” which help fight off infections.

Sometimes necessary treatments for certain medical conditions can also cause secondary immunodeficiency. For example, people with autoimmune disorders—which cause the immune system to become overactive and attack healthy cells—may need to take immunosuppressant drugs to manage their symptoms. However, the drugs can make them more vulnerable to infection. 

People who receive organ transplants may also need to take immunosuppressant medications for life to prevent their body from rejecting the new organ. (Given the risk of infection, scientists continue to research alternative ways for the immune system to tolerate transplantation.)

Chemotherapy for cancer patients can also cause secondary immunodeficiency because it kills the immune system’s white blood cells as it’s trying to kill cancer cells.

What are the symptoms of a compromised immune system?

People who are immunocompromised may become sick more frequently than others or may experience more severe or longer-term symptoms than others who contract the same disease.

Other symptoms of a compromised immune system may include fatigue; digestive problems like cramping, nausea, and diarrhea; and slow wound healing.

How can I find out if I’m immunocompromised?

If you think you may be immunocompromised, talk to your health care provider about your medical history, your symptoms, and any medications you take. Blood tests can determine whether your immune system is producing adequate proteins and cells to fight off infection.

I’m immunocompromised—how can I protect myself from infection?

If you’re immunocompromised, take precautions to protect yourself from illness.

Wash your hands regularly, wear a well-fitting mask around others to protect against respiratory viruses, and ensure that you’re up to date on recommended vaccines.

Immunocompromised people may need more doses of vaccines than people who are not immunocompromised—including COVID-19 vaccines. Talk to your health care provider about which vaccines you need.

How can I protect the immunocompromised people around me?

You never know who may be immunocompromised. The best way to protect immunocompromised people around you is to avoid spreading illnesses. 

If you know you’re sick, isolate whenever possible. Wear a well-fitting mask around others—especially if you know that you’re sick or that you’ve been exposed to germs. Make sure you’re up to date on recommended vaccines, and practice regular hand-washing.

If you’re planning to spend time with someone who is immunocompromised, ask them what steps you can take to keep them safe.

For more information, talk to your health care provider.

This article first appeared on Public Good News and is republished here under a Creative Commons license.

The U.S. Department of Health and Human Services is responsible for programs that impact every community in the country. But most Americans aren’t aware of the department’s scope.

“Most of the power in the agency, most of the administrative authority comes from laws that Congress has passed,” former HHS Secretary Kathleen Sebelius told NPR. She added that the HHS secretary “could redefine terms that had a huge impact on people. And that could be done all administratively, not by going back to Congress.”

HHS is comprised of 13 agencies, all of which play an important role in promoting the health of all Americans. These are just some of the ways that HHS affects people’s lives and health.

Vaccines

One of HHS’s most salient roles is developing, approving, and monitoring vaccines after they are on the market. The National Institutes of Health funds and conducts research to develop new vaccines and improve existing ones. The NIH’s Vaccine Research Center spearheads research to develop vaccines against deadly diseases like HIV/AIDS, malaria, and tuberculosis.

The Food and Drug Administration is responsible for overseeing clinical trials that test product safety and effectiveness, approving new vaccines, and monitoring the safety of all vaccines before and after approval. In conjunction with the Centers for Disease Control and Prevention, the FDA also manages the national surveillance systems that record and flag potential vaccine side effects. 

In addition to safety monitoring, the CDC conducts research on vaccine safety and effectiveness and issues vaccination guidance. The agency’s recommended immunization schedule guides school and child care vaccination requirements and health care provider recommendations nationwide. 

Although the CDC does not have the authority over school and childcare vaccination requirements at the state level, changes to the agency’s recommendations could have wide-ranging impacts. 

“If this recommendation changes, there’s downstream effects, like insurance companies could stop covering them. And adding cost could easily deter uptake,” epidemiologist and creator of the Your Local Epidemiologist newsletter Katelyn Jetelina told PBS. 

However, CDC vaccine recommendations are just that: recommendations. The agency cannot dictate, for example, vaccine requirements for school enrollment. Those standards are set at the state level, with the possible exception during a national public health emergency. 

Drug safety 

The FDA oversees all clinical trials in the United States. Every prescription drug and many medical products undergo a rigorous, closely regulated, multistep trial to test their safety and effectiveness. At the end of that process, the FDA determines whether a drug meets its standards for approval. Without FDA approval, a drug cannot be sold in the U.S.

Like with vaccines, the FDA monitors potential safety concerns related to over-the-counter and prescription medications, medical devices, and other products the agency regulates. Health care providers, FDA-regulated companies, and patients can report suspected safety issues to the agency, which evaluates each report for further investigation. 

The FDA also alerts the public to safety concerns related to medical products by releasing safety notices, adding warning labels, and issuing drug recalls.

Pandemic and public health emergency response

Several HHS agencies are tasked with preventing, preparing for, and responding to disease outbreaks. This responsibility includes tracking potentially dangerous infectious diseases in the U.S. and globally, developing pandemic response strategies, and issuing guidance to contain ongoing outbreaks. 

Both the CDC and FDA inform the public about public health concerns, including pandemics. The Administration for Strategic Preparedness and Response works with communities, medical facilities, local and state governments, and industry partners to enhance responses to disasters and public health emergencies. 

The CDC also tracks pathogens like the flu, norovirus, and sexually transmitted infections to better understand where diseases are spreading, how they are evolving, and how best to prepare for outbreaks.

In the event of a public health emergency, the CDC may issue guidance on how to stay safe and minimize health impacts. For example, in January, the agency released tips on how to protect against smoke during the wildfires affecting southern California and how to avoid frostbite and hypothermia, as extreme cold weather affected much of the country. 

The FDA can issue emergency use authorizations, which allow the use of “unapproved medical products or unapproved uses of approved medical products … to diagnose, treat, or prevent serious or life-threatening diseases … when certain criteria are met” during public health emergencies. These authorizations help ensure that the standard FDA approval process is not a barrier to the public receiving lifesaving medical products, such as authorizing specific vaccines during a pandemic. 

Food and water safety

The FDA, along with the U.S. Department of Agriculture, plays an important role in regulating food safety. The agency approves and monitors the safety of food additives, like sweeteners, dyes, and preservatives. It also regulates how food is prepared, packaged, and stored, including conducting inspections of food facilities and farms. 

FDA food safety testing detects dangerous foodborne illnesses like salmonella and E. coli. For example, in late December 2024, the FDA began testing raw (unpasteurized) milk products for bird flu contamination. The CDC investigates outbreaks of foodborne illnesses and, along with the FDA and USDA, provides the public with information about food safety. 

The FDA also regulates most food labels, including nutrition facts, ingredient lists, and health claims on food packaging. In January, the agency proposed new front-of-package nutrition labels that highlight sugar, fat, and sodium content in packaged food products. 

HHS and the USDA are responsible for updating the Dietary Guidelines for Americans, which are updated every five years. These guidelines are the basis of all federal food assistance programs for children, older adults, and low-income families.

HHS sets the guidelines for the maximum fluoride level in drinking water and periodically makes recommendations about fluoride levels. However, the department has no authority to require or ban fluoridation, which is regulated at the state and local level. U.S. cities began adding fluoride to drinking water in the 1940s to improve dental health and reduce cavities by 25 percent. 

Health care access

The HHS secretary regulates the Centers for Medicare & Medicaid Services, which provides health insurance to adults 65 and older, people with disabilities, low-income families, and eligible children through the Children’s Health Insurance Program. Together, Medicare, Medicaid, and CHIP insure over 145 million Americans, or roughly 42 percent of the U.S. population. Changes to either of these programs could impact health care access and quality for millions of Americans.

This article first appeared on Public Good News and is republished here under a Creative Commons license.