Is it possible for someone who has previously had mumps to be reinfected?

Hey, regarding this question, I can share my understanding.

Generally speaking, the vast majority of people who have had mumps once will acquire lifelong immunity and generally won't get it again.

It's like our body, after battling the virus for the first time, completely remembers what this "enemy" looks like. The next time it encounters the same virus, the body's "immune army" can quickly recognize and eliminate it, not giving you a second chance to get sick.

However, there are always exceptions

In some very rare cases, some people do get mumps a second time. This could be due to several reasons:

1. Immunity 'fades'

   • Although the body has memory, for a small number of people, this memory might gradually fade over time (e.g., after many, many years). If antibody levels drop to a certain extent and they are exposed to a large amount of mumps virus again, they might get infected again. However, the symptoms of the second infection are usually much milder than the first.

2. The first time might have been 'false' mumps

   • This is a common situation. The symptoms of some other diseases are very similar to mumps, such as salivary gland inflammation or swollen lymph nodes caused by other viruses. You might have thought you had mumps, but you actually didn't. In such a case, your body wouldn't have developed "immune memory" specifically against the mumps virus, so when you genuinely get infected with the mumps virus later, you'll develop the illness, leading you to mistakenly believe it was a "recurrence."

3. The first infection was too 'mild'

   • If the symptoms during the first infection were very mild, or you didn't even notice them yourself (medically known as a "subclinical infection"), then the immunity produced by your body might not be strong and lasting enough to protect you for life.

In summary

• Rest assured, the probability of getting infected with mumps again after having it once is extremely low. For most ordinary people, it can be considered that having had it once grants lifelong immunity.
• The immunity acquired through vaccination follows the same principle; it's very effective, but its protective effect might also wane over time.
• If you or someone around you develops mumps-like symptoms, and they have had it before, it's best to go to the hospital and have a doctor examine it. This can help get a clear diagnosis, rule out other issues, and ensure the most appropriate treatment.

Hope this explanation helps you!