
What childhood illnesses can adults get?
Peer reviewed by Dr Colin Tidy, MRCGPLast updated by Josh AldermanLast updated 26 Jul 2026
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Many illnesses are commonly associated with children, but adults can catch them too. In some cases, adults may experience more severe symptoms or have a higher risk of complications than children.
Childhood illnesses are often caused by infections that spread easily through close contact, coughing, sneezing, or touching contaminated surfaces.
Vaccinations provide protection against many of these conditions, but immunity can sometimes reduce over time.
Why do adults sometimes get childhood illnesses?
Adults can catch childhood illnesses if they:
Have not been vaccinated.
Have never had the infection before.
Have lost some immunity over time.
Adults who are also in close contact with children, such as parents, grandparents, teachers, and childcare workers, are also more likely to be exposed.
Adults may sometimes experience more severe symptoms because their immune response can differ from that of children.
Certain groups may have a higher risk of complications, these include:
Pregnant people.
Older adults.
Those with weakened immune systems.
What childhood illness do adults sometimes get?
Chickenpox
Chickenpox is a common childhood infection caused by the varicella-zoster virus. It usually causes an itchy, blistering rash, fever, and tiredness.
Adults can catch chickenpox if they have not had the infection before or have not been vaccinated. Chickenpox is often more severe in adults than children and can sometimes lead to complications, such as pneumonia.
Pregnant people who develop chickenpox should seek medical advice because the infection can sometimes affect both parent and baby.
Measles
Measles is a highly infectious viral illness that causes symptoms including a high fever, cough, runny nose, sore eyes, and a rash.
Although it is often thought of as a childhood illness, adults can catch measles if they are not immune. Adults may be more likely to experience complications, which can include pneumonia, ear infections, or, rarely, inflammation of the brain.
The measles, mumps, and rubella (MMR) vaccine provides protection against measles.
Mumps
Mumps is a viral infection that commonly causes swelling of the glands at the side of your face and jaw, known as the parotid glands. Other symptoms can include fever, headache, and tiredness.
Adults who catch mumps may be more likely to develop complications, such as inflammation of the testicles or ovaries, and, rarely, meningitis.
Whooping cough
Whooping cough, also called pertussis, is a bacterial infection that causes severe coughing bouts. The cough can last for several weeks or even months.
Adults can catch whooping cough, especially if their childhood vaccination protection has reduced. While it is usually less serious in adults, they can pass it on to babies, who are at higher risk of severe illness.
Hand, foot, and mouth disease
Hand, foot, and mouth disease is a viral infection that commonly affects young children. It causes mouth ulcers and a rash or blisters on your hands and feet.
Adults can also catch it, although symptoms may be mild or they may have no symptoms at all. Some adults experience a sore throat, fever, or a more widespread rash.
Slapped cheek syndrome
Slapped cheek syndrome, also known as fifth disease, is caused by parvovirus B19. It usually causes a bright red rash on the cheeks in children.
Adults can catch the infection and may develop joint pain or swelling, rather than the typical rash seen in children. Pregnant people who catch slapped cheek syndrome should seek medical advice.
Scarlet fever
Scarlet fever is caused by group A Streptococcus bacteria. It commonly causes a sore throat, fever, and a fine, rough rash that feels similar to sandpaper.
Although it is more common in children, adults can catch scarlet fever. Treatment may involve antibiotics to reduce the risk of complications and prevent the spread of infection.
Rubella
Rubella, also called German measles, is a viral infection that is usually mild in children and adults. Symptoms can include a rash, fever, and swollen glands.
Rubella is particularly important during pregnancy because it can cause serious problems for an unborn baby. The MMR vaccine protects against rubella.
Threadworms
Threadworms are small parasitic worms that commonly affect children but can also infect adults. They spread when eggs are swallowed, often after contact with contaminated hands, bedding, or surfaces.
Symptoms can include itching around your anus, especially at night. Treatment usually involves medication and careful hygiene measures to prevent reinfection.
Headlice
Headlice are tiny insects that live in your hair and are spread through close head-to-head contact. They are common among children but can affect people of any age.
Having headlice is not linked to poor hygiene. Treatment for headlice involves using appropriate products to remove the lice and their eggs, along with checking close contacts where necessary.
Which childhood illnesses are the most dangerous for adults?
Most childhood illnesses cause mild symptoms in adults and get better without treatment. However, some infections can be more serious and are more likely to cause complications.
The childhood illnesses most likely to cause serious illness in adults include:
Chickenpox.
Measles.
Whooping cough.
Rubella.
The risk of complications is highest if you are:
Pregnant.
Immunocompromised (have a weakened immune system).
Caring for or in close contact with young babies.
If you develop symptoms of one of these illnesses and are pregnant, have a weakened immune system, or feel very unwell, seek medical advice as soon as possible.
Can adults protect themselves from childhood illnesses?
There are some things that you can do as an adult to help protect yourself from catching childhood illnesses.
These include:
Checking that their vaccinations are up to date, including the MMR vaccine where appropriate.
Washing hands regularly, especially after contact with children who are unwell.
Avoiding sharing cups, cutlery, or personal items with someone who has an infection.
Seeking medical advice if they have been exposed to certain infections and are at higher risk of complications.
Keeping children’s vaccinations up to date to reduce the spread of infections.
Summary
Adults can catch many childhood illnesses including chickenpox, measles, mumps, whooping cough, and hand, foot and mouth disease.
An adult is more at risk of catching childhood illnesses if they have not been vaccinated or have not previously had the infection.
Staying up to date with vaccinations and practising good hygiene can help reduce the risk of catching and spreading these infections.
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Article history
The information on this page is peer reviewed by qualified clinicians.
Article also available in English, German, Spanish, French, Italian, Portuguese, Hindi, Hebrew, Arabic, and Swedish.
Next review due: 26 Jul 2029
26 Jul 2026 | Latest version
29 Jul 2019 | Originally published
Authored by:
Dr Sarah Jarvis

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