Mumps is a viral infection spread through saliva and respiratory droplets

Mumps virus causes swelling in the salivary glands—the glands that make saliva in your mouth and jaw. The virus spreads when an infected person coughs, sneezes, or shares food or drinks with someone else. You catch it by breathing in those droplets or by touching your face after contact with an infected person's saliva. Once you have mumps, the virus takes about two to three weeks to show symptoms, though some people never develop noticeable signs at all.

The virus belongs to a family called paramyxoviruses, which also includes measles and rubella. Mumps is contagious from about two days before symptoms appear until five days after the swelling starts. This means people can spread it without knowing they have it, which is why outbreaks still happen even in vaccinated populations when immunity wanes.

Key Takeaways

  • Mumps spreads through saliva and respiratory droplets when an infected person coughs, sneezes, or shares food and drinks.
  • Symptoms typically appear two to three weeks after exposure, with swollen salivary glands being the most recognizable sign.
  • A person with mumps can spread the virus to others from two days before symptoms start until five days after swelling begins.
  • The MMR vaccine prevents most mumps infections, but immunity can decrease over time, which is why some vaccinated people still contract it.

How the virus enters and moves through your body

When you inhale mumps virus particles or the virus touches the inside of your mouth or nose, it attaches to cells in your respiratory tract. From there, it travels to your salivary glands—the parotid glands on the sides of your face are the most commonly affected. The virus multiplies inside these gland cells, causing inflammation and the characteristic puffy cheeks and jaw swelling.

In some cases, the virus spreads beyond the salivary glands to other parts of your body. It can reach the brain and spinal cord, causing meningitis or encephalitis. It can also affect the pancreas, testicles, ovaries, or inner ear. This is why mumps can cause hearing loss, fertility problems, or neurological symptoms in some people, even though most infections stay localized to the salivary glands.

What happens in your body when you have mumps

Your immune system recognizes the mumps virus as a threat and launches an inflammatory response. This inflammation is what causes the swelling in your salivary glands, along with fever, body aches, and fatigue. The swelling usually peaks around three to five days after it starts, then gradually goes down over the next week or two. During this time, your body is also producing antibodies—proteins that recognize and fight the virus.

Once you recover from mumps, your immune system remembers the virus. This is why mumps immunity typically lasts your whole life after natural infection. However, immunity from the MMR vaccine can weaken over decades, which is why some people who were vaccinated years ago can still get mumps if they encounter the virus again.

Why the MMR vaccine prevents mumps but not always

The MMR vaccine contains a weakened form of the mumps virus that trains your immune system to recognize and fight the real virus without causing the disease. Two doses of the vaccine prevent mumps in about 88 percent of people who receive them. One dose is roughly 78 percent protective. This means the vaccine works well for most people, but not everyone who is vaccinated will be protected if they encounter the virus.

Vaccine effectiveness also depends on when you were vaccinated. People who received the MMR vaccine decades ago may have declining immunity now. Additionally, some people's immune systems do not respond as well to the vaccine as others do—this can happen due to age, genetics, or certain medical conditions. This is why mumps outbreaks can still occur in communities with high vaccination rates.

Symptoms that appear as the virus multiplies

The first signs of mumps are usually fever, headache, muscle aches, and fatigue. These symptoms can feel like a cold or flu and may appear for a day or two before the characteristic swelling starts. Once the salivary glands become inflamed, you will notice puffy cheeks and a swollen jaw. Chewing and swallowing become painful. Some people also develop a sore throat or loss of appetite.

Not everyone with mumps develops the classic swollen cheeks. Some people have mild symptoms or no symptoms at all, even though they carry the virus and can spread it. This is called asymptomatic mumps. In other cases, the virus affects organs beyond the salivary glands, causing symptoms like severe headache, stiff neck, hearing loss, or abdominal pain. These complications are less common but more serious.

Who is most at risk of severe mumps

Adults tend to have more severe mumps than children. Men who contract mumps after puberty face a risk of orchitis—inflammation of the testicles—which occurs in about one-third of infected adult males. This can cause pain, swelling, and in rare cases, fertility problems. Women can develop oophoritis, inflammation of the ovaries, though this is less common and typically does not affect fertility.

People with weakened immune systems, pregnant people, and those with certain medical conditions may experience more serious complications. Meningitis and encephalitis, while uncommon, are more likely in people whose immune systems cannot fight the virus effectively. Hearing loss from mumps can be permanent and may occur suddenly, even weeks after the initial infection resolves.

Testing and confirming mumps infection

Mumps is diagnosed through a combination of symptoms and laboratory tests. A healthcare provider may order a saliva test, blood test, or cerebrospinal fluid test to confirm the virus. The saliva test is most accurate when done within three days of symptom onset. Blood tests look for mumps antibodies—the proteins your immune system makes to fight the virus. These antibodies appear a few days after symptoms start and remain in your blood for years.

Because mumps symptoms can resemble other viral infections, testing is important to confirm the diagnosis, especially if complications are suspected. If meningitis or encephalitis is a concern, a lumbar puncture may be performed to test the fluid around your brain and spinal cord. Once mumps is confirmed, there is no specific treatment—care focuses on managing fever and pain while your immune system clears the virus.

Frequently Asked Questions

Can you get mumps more than once?

Natural mumps infection typically provides lifelong immunity, so getting it twice is rare. However, immunity from the MMR vaccine can fade over time, which is why some vaccinated people can contract mumps years after vaccination. Once you recover from natural mumps, you are protected for life.

Is mumps still common today?

Mumps is much less common than it was before the MMR vaccine became widespread in the 1970s. However, outbreaks still occur, particularly in communities with lower vaccination rates or among people whose vaccine immunity has waned. The disease has not been eliminated.

Can mumps cause permanent damage?

Most people recover from mumps without lasting effects. However, mumps can cause permanent hearing loss, which may occur suddenly and affect one or both ears. Fertility problems from orchitis or oophoritis are possible but uncommon. Meningitis or encephalitis, while rare, can have serious long-term consequences.

How long does it take to recover from mumps?

The swelling and fever typically peak within three to five days and gradually improve over one to two weeks. Most people feel better within a week or two, though fatigue can linger longer. Full recovery usually takes two to three weeks from the start of symptoms.

What should you do if you think you have mumps?

Contact a healthcare provider for testing and confirmation. Stay home and avoid close contact with others for at least five days after swelling starts to prevent spreading the virus. Rest, drink fluids, and use over-the-counter fever and pain relievers as directed. Seek immediate care if you develop severe headache, stiff neck, or hearing changes.