immunoprophylaxis

Vaccines are injections (shots), liquids, pills, or nasal sprays that you take to teach your body's immune system to recognize and defend against harmful germs. For example, there are vaccines to protect against diseases caused by:

• Viruses, like the ones that cause the flu and COVID-19
• Bacteria, including tetanus, diphtheria, and pertussis

There are several types of vaccines:

• Live-attenuated vaccines use a weakened form of the germ.
• Inactivated vaccines use a killed version of the germ.
• Subunit, recombinant, polysaccharide, and conjugate vaccines use only specific pieces of the germ, such as its protein, sugar, or casing.
• Toxoid vaccines use a toxin (harmful product) made by the germ.
• mRNA vaccines use messenger RNA, which gives your cells instructions for how to make a protein (or piece of a protein) of the germ.
• Viral vector vaccines use genetic material, which gives your cells instructions for making a protein of the germ. These vaccines also contain a different, harmless virus that helps get the genetic material into your cells.

These vaccines may work in different ways, but they all spark an immune response. The immune response is the way your body defends itself against substances it sees as foreign or harmful. These substances include germs that can cause disease.

There are different steps in the immune response:

• When a germ invades, your body sees it as foreign.
• Your immune system helps your body fight off the germ.
• Your immune system also remembers the germ. It will attack the germ if it ever invades again. This "memory" protects you against the disease that the germ causes. This type of protection is called immunity.

Immunization is the process of becoming protected against a disease. But it can also mean the same thing as vaccination, which is getting a vaccine to become protected against a disease.

Vaccines are important because they protect you against many diseases. These diseases can be very serious. So getting immunity from a vaccine is safer than getting immunity by being sick with the disease.

For a few vaccines, getting vaccinated can actually give you a better immune response than getting the disease would.

But vaccines don't just protect you. They also protect the people around you through community immunity.

Community immunity, or herd immunity, is the idea that vaccines can help keep communities healthy.

Normally, germs can travel quickly through a community and make a lot of people sick. If enough people get sick, it can lead to an outbreak. But when enough people are vaccinated against a certain disease, it's harder for that disease to spread to others. This type of protection means that the entire community is less likely to get the disease.

Community immunity is especially important for people who can't get certain vaccines. For example, they may not be able to get a vaccine because they have weakened immune systems. Others may be allergic to certain vaccine ingredients. And newborn babies are too young to get some vaccines. Community immunity can help to protect them all.

Vaccines are safe. They must go through extensive safety testing and evaluation before they are approved in the United States.

A vaccine, or immunization, schedule lists which vaccines are recommended for different groups of people. It includes who should get the vaccines, how many doses they need, and when they should get them. In the United States, the Centers for Disease Control and Prevention (CDC) publishes the vaccine schedule.

It's important for both children and adults to get their vaccines according to the schedule. Following the schedule allows them to get protection from the diseases at exactly the right time.

Vaccines are injections (shots), liquids, pills, or nasal sprays that you take to teach the immune system to recognize and defend against harmful germs. The germs could be viruses or bacteria.

Some types of vaccines contain germs that cause disease. But the germs have been killed or weakened enough that they won't make your child sick. Some vaccines only contain a part of a germ. Other types of vaccines include instructions for your cells to make a protein of the germ.

These different vaccine types all spark an immune response, which helps the body fight off the germs. Your child's immune system will also remember the germ and attack it if that germ ever invades again. This protection against a certain disease is called immunity.

Babies are born with immune systems that can fight most germs, but there are some serious diseases they can't handle. That's why they need vaccines to strengthen their immune system.

These diseases once killed or harmed many infants, children, and adults. But now with vaccines, your child can get immunity from these diseases without having to get sick. And for a few vaccines, getting vaccinated can actually give you a better immune response than getting the disease would.

Vaccinating your child also protects others. Normally, germs can travel quickly through a community and make a lot of people sick. If enough people get sick, it can lead to an outbreak. But when enough people are vaccinated against a certain disease, it's harder for that disease to spread to others. The entire community is less likely to get the disease. This is called "community immunity."

Community immunity is especially important for the people who can't get certain vaccines. For example, they may not be able to get a vaccine because they have weakened immune systems. Others may be allergic to certain vaccine ingredients. And newborn babies are too young to get some vaccines. Community immunity can help to protect them all.

Vaccines are safe. They must go through extensive safety testing and evaluation before they are approved in the United States.

Some people worry that childhood vaccines could cause autism spectrum disorder (ASD). But many scientific studies have looked at this and have found no link between vaccines and autism.

No, vaccines do not overload the immune system. Every day, a healthy child's immune system successfully fights off thousands of germs. When your child gets vaccines, they are getting weakened or dead germs. So even if they get several vaccines in one day, they are being exposed to a tiny amount of germs compared to what they encounter every day in their environment.

Your child will get vaccines during well-child visits. They will be given according to the vaccine schedule. This schedule lists which vaccines are recommended for children. It includes who should get the vaccines, how many doses they need, and at what age they should get them. In the United States, the Centers for Disease Control and Prevention (CDC) publishes the vaccine schedule.

Following the vaccine schedule allows your child to get protection from the diseases at exactly the right time. It gives their body the chance to build up immunity before being exposed to these very serious diseases.

Every racial or ethnic group has specific health concerns. Differences in the health of groups can result from:

• Genetics
• Environmental factors
• Access to care
• Cultural factors

On this page, you'll find links to health issues that affect Asian Americans.

Diabetes, also known as diabetes mellitus, is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose is your body's main source of energy. Your body can make glucose, but it also comes from the food you eat. Insulin is a hormone made by your pancreas. Insulin helps move glucose from your bloodstream into your cells, where it can be used for energy.

If you have diabetes, your body can't make insulin, can't use insulin as well as it should, or both. Too much glucose stays in your blood and doesn't reach your cells. This can cause glucose levels to get too high. Over time, high blood glucose levels can lead to serious health conditions. But you can take steps to manage your diabetes and try to prevent these health problems.

There are different types of diabetes:

• Type 1 diabetes. If you have type 1 diabetes, your body makes little or no insulin. It happens when your immune system attacks and destroys the cells that produce insulin.
• Type 2 diabetes. This is the most common form of diabetes. If you have type 2 diabetes, your body may still be able to make insulin, but your cells don't respond well to insulin. They can't easily take up enough glucose from your blood.
• Gestational diabetes. This is a form of diabetes that develops during pregnancy. It happens when your body can't make the extra insulin it needs during pregnancy.

The different types of diabetes have different causes:

• Researchers think type 1 diabetes is caused by genes and factors in the environment that might trigger the disease.
• Type 2 diabetes is caused by several factors, including lifestyle factors and genes. The lifestyle factors include not being physically active and being overweight or having obesity.
• Researchers think gestational diabetes is caused by the hormonal changes of pregnancy along with genetic and lifestyle factors.

The different types of diabetes have different risk factors:

• You can develop type 1 diabetes at any age, but it most often starts in childhood. Having a parent or sibling with type 1 diabetes may increase your chance of developing it.
• You are at higher risk of developing type 2 diabetes if you:
• Are overweight or have obesity.
• Are over age 35. Children, teenagers, and younger adults can get diabetes, but it is more common in middle-aged and older adults.
• Have a family history of diabetes.
• Have prediabetes. This means that your blood glucose is higher than normal, but it's not high enough to be called diabetes.
• Had gestational diabetes.
• Have given birth to a baby weighing 9 pounds or more.
• Are African American, American Indian, Asian American, Hispanic/Latino, or Pacific Islander.
• Are not physically active.
• Have certain other health conditions, such as high blood pressure or polycystic ovary syndrome (PCOS).
• You are at higher risk of developing gestational diabetes if you:
• Are overweight or have obesity.
• Have a family history of diabetes.
• Had gestational diabetes in a previous pregnancy.
• Have given birth to a baby weighing 9 pounds or more.
• Have polycystic ovary syndrome (PCOS).
• Are African American, Hispanic/Latino, American Indian, Alaska Native, Native Hawaiian, or Pacific Islander.

The symptoms of diabetes may include:

• Feeling very thirsty
• Feeling very hungry
• Urinating (peeing) more often, including at night
• Fatigue
• Blurry vision
• Numbness or tingling in the feet or hands
• Sores that do not heal
• Losing weight without trying

But it's important to know that your symptoms may vary, depending on which type you have:

• The symptoms of type 1 diabetes usually come on quickly and can be severe.
• With type 2 diabetes, the symptoms often develop slowly, over several years. The symptoms can be so mild that you might not even notice them.
• Gestational diabetes often has no symptoms. If you do have symptoms, they may be mild. People who are pregnant are usually screened for this condition between 24 and 28 weeks of pregnancy.

To find out if you have diabetes, your health care provider will use one or more glucose blood tests. There are several types, including the A1C test.

Treatment for diabetes involves managing your blood glucose levels:

• If you have type 1 diabetes, you will need to take daily doses of insulin, either by injection or through a special pump. Some people also need to take another type of diabetes medicine that works with insulin.
• If you have type 2 diabetes, you may be able to manage or even reverse it by making lifestyle changes. These include eating a healthy diet, staying at healthy weight, and getting regular physical activity. Some people also need to take diabetes medicines to manage their diabetes.
• If you have gestational diabetes, you may be able to lower your glucose levels by eating a healthy diet and getting regular exercise. But be sure to talk to your provider about your treatment options. Gestational diabetes usually goes away after you give birth. But you will have a higher risk of developing type 2 diabetes later.

Checking your blood glucose levels is also an important part of managing your diabetes. Ask your provider about the best way to check your blood glucose level and how often you should check it.

Type 1 diabetes can't be prevented.

You may be able to delay or prevent type 2 diabetes through the same lifestyle changes that are used to manage diabetes (eating a healthy diet, staying at a healthy weight, and getting regular physical activity). These lifestyle changes may also help prevent gestational diabetes.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

The flu (influenza) is a respiratory infection. It is caused by influenza viruses that infect your nose, throat, and lungs. These viruses can spread from person to person.

Most people with the flu get better on their own, without medical care. But for some people, the flu is serious. It can cause complications and sometimes even death. People who are 65 and older, under age 5, pregnant, or have certain health conditions are at higher risk of flu complications.

Getting vaccinated against the flu each year is best way to lower your risk of the flu and its complications.

There are many reasons to get a flu shot each year:

• It may keep you from getting sick with the flu.
• If you do get the flu, it may be less severe. You may also be less likely to have complications or need to be hospitalized with the flu.
• If you have certain chronic health conditions, getting a flu shot may help prevent the flu from making your condition worse. For example, if you have COPD or diabetes, the flu can worsen your condition so much that you might need to be hospitalized. Getting a flu shot can lower this risk.
• Getting the vaccine during pregnancy not only helps protect you from the flu during and after pregnancy. It also helps protect your baby from flu during their first few months of life.
• It has been shown to lower the risk of severe life-threatening flu in children.
• It may also protect the people around you, including those who are at higher risk of complications.

The flu vaccine causes your immune system to make antibodies about two weeks after you get the shot. These antibodies provide protection against infection with the flu viruses that are in the vaccine.

The U.S Centers for Disease Control and Prevention (CDC) recommends annual flu shots for everyone 6 months and older, with a few rare exceptions.

Flu shots are especially important for people who are at high risk of developing serious complications from the flu.

There are different types of flu vaccines. There are injectable vaccines (shots) and nasal spray vaccines. There are also some vaccines especially for people 65 and older. Ask your health care provider which one is right for you.

There are some people who should not get a flu shot:

• Children younger than 6 months of age.
• Have severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine. This might include gelatin, antibiotics, or other ingredients.

Some people need to talk to their provider before they get a flu shot. They include people who:

• Have an allergy to any of the ingredients in the vaccine.
• Have ever had Guillain-Barre syndrome(GBS). Some people with a history of GBS should not get a flu vaccine.

If you are moderately or severely ill, you usually need to wait until you recover before getting a flu shot.

You need to get a flu shot every year because:

• Your immune protection from the vaccine declines over time. You need to get the shot every year to boost that protection.
• Flu viruses are constantly changing, so every year, the flu vaccine is updated. The flu vaccine will include protection against the viruses that will most likely be common during the upcoming flu season.

For most people who need only one dose of the flu vaccine for the season, September and October are usually good times to get it. It's best to be vaccinated by the end of October.

Some children need two doses of the flu vaccine. They should get their first dose as soon as the vaccine is available. They need to get the second dose at least four weeks after the first.

If you are pregnant, talk to your provider about when to get the vaccine. When you should get it can vary, based on how far along you are in your pregnancy.

Flu vaccines have been shown to be safe. But like any medical product, they can cause side effects. If you have any side effects, they are usually mild and go away on their own within a few days. Common side effects include:

• Soreness, redness, and/or swelling from the shot
• Headache
• Fever
• Nausea
• Muscle aches

The flu shot, like other injections, can occasionally cause fainting. In rare cases, some people have a serious allergic reaction.

Centers for Disease Control and Prevention

The spread of a disease doesn't stop at a country's borders. With more people living in crowded cities and traveling to other countries, it's easier for germs to spread. Infectious diseases that start in one part of the world can quickly reach another part of the world. Some of the major diseases currently affecting countries around the globe include HIV, malaria, COVID-19, and tuberculosis.

Besides the spread of diseases, there are other global health challenges. Resistance to medicines such as antibiotics is on the rise. That makes it harder to treat certain diseases. Natural and man-made disasters create refugee populations with immediate and long-term health problems. Climate change and not enough access to food and safe water are also global problems which can affect people's health. Many countries and health organizations are working together and sharing information on these and other health issues.

Regular checkups with your health care provider are different from appointments for sickness or injury. These checkups include physical exams as well as preventive care. Preventative care may include:

• Screening tests, which are medical tests to check for diseases early, when they may be easier to treat. Which screenings you need will depend on your:
  • Age
  • Sex
  • Overall health
  • Family health history
  • Risks for certain diseases
• Vaccines, which can improve your health by preventing diseases and other health problems.
• Education and counseling to help you make informed health decisions. This could include advice about your lifestyle, including your diet, how much exercise you get, and any alcohol, tobacco, or other substances you may be using.

To make the most of your next check-up, here are some things to do before you go:

• Review your family health history
• Find out if you are due for any general screenings or vaccines
• Make and bring a list of issues and questions you would like to talk about with your provider
• Make and bring a list of any medicines, vitamins, supplements that you take

Centers for Disease Control and Prevention

Having HIV/AIDS weakens your body's immune system. It destroys the white blood cells that fight infection. This puts you at risk for opportunistic infections (OIs). OIs are serious infections that take advantage of your weak immune system. These infections are less common and less severe in healthy people.

There are many types of OIs:

• Bacterial infections, including tuberculosis and a serious related disease, Mycobacterium avium complex (MAC)
• Viral infections, such as cytomegalovirus (CMV) and hepatitis C
• Fungal infections, like yeast infections, cryptococcal meningitis, pneumocystis carinii pneumonia (PCP) and histoplasmosis
• Parasitic infections, such as crypto (cryptosporidiosis) and toxo (toxoplasmosis)

Having HIV/AIDS can make infections harder to treat. People with HIV/AIDS are also more likely to have complications from common illnesses such as the flu.

You can help prevent infections by taking your HIV/AIDS medicines. Other things that can help include practicing safe sex, washing your hands well and often, and cooking your food thoroughly.

Every racial or ethnic group has specific health concerns. Differences in the health of groups can result from:

• Genetics
• Environmental factors
• Access to care
• Cultural factors

On this page, you'll find links to health issues that affect Latino and Hispanic Americans.

HIV stands for human immunodeficiency virus. It harms your immune system by destroying a type of white blood cell that helps your body fight infection.

AIDS is the final stage of infection with HIV. It happens when the body's immune system is badly damaged because of the virus. Not everyone with HIV develops AIDS.

There is no cure for HIV, but there are many medicines to treat both HIV infection and the health problems and infections (called opportunistic infections, or OIs) that come with it. The medicines allow people with HIV to have long, healthy lives.

IIf you have HIV, you can help yourself by:

• Getting medical care as soon as you find out that you have HIV. You should find a health care provider who has experience in treating HIV.
• Taking your medicines every day.
• Letting your provider know if you get any new symptoms or health problems.
• Keeping up with your regular medical and dental care.This includes staying up to date with your recommended health screenings and vaccinations. Your provider can let you know which ones you need.
• Managing stress and getting support, such as from support groups, therapists, and social service organizations
• Trying to live a healthy lifestyle, including:
• Eating healthy foods.This can give your body the energy it needs to fight HIV and other infections. It can help you manage HIV symptoms and medicine side effects. It may also improve absorption of your HIV medicines.
• Getting regular physical activity. This can strengthen your body and immune system. It may also reduce the risk of depression.
• Getting enough sleep. Sleep is important for your physical strength and mental health.
• Not smoking. People with HIV who smoke have a higher risk of developing conditions such as certain cancers and infections. Smoking can also interfere with your medicines. Talk to your provider if you need help quitting smoking.
• Avoiding heavy drinking or taking illegal drugs. They can damage your liver, which means your HIV medicine may not work as well. They can also make it harder for your body to fight infections.
• Protecting yourself from OIs. Talk to your provider about medicines and vaccines that prevent certain OIs. Also, be careful to avoid exposure to contaminated food and water.

It is also important to reduce the risk of spreading HIV to other people. You should tell your sex partners that you have HIV and always use latex condoms. If your or your partner is allergic to latex, you can use polyurethane condoms.