Mumps is a viral infection that causes swelling in the salivary glands, particularly those located near the ears. While often considered a childhood illness, mumps can affect individuals of any age, especially those who are unvaccinated. A common concern among males is whether mumps can lead to sterility; while possible, it is generally a rare complication.
Mumps and Its Complications
Mumps is caused by the mumps virus, a member of the paramyxovirus family, and spreads through respiratory droplets. The infection presents with symptoms such as fever, headache, muscle aches, and painful swelling of the parotid salivary glands. While many individuals recover without lasting issues, the virus can spread to other parts of the body, leading to complications.
One of the most concerning complications for males is orchitis, the inflammation of one or both testicles. This condition appears 4 to 7 days after initial mumps symptoms, though it can manifest up to six weeks later. Orchitis is more common in males who contract mumps after puberty, affecting about 20% to 38% of this group.
How Mumps Impacts Male Fertility
When the mumps virus reaches the testicles, it causes mumps orchitis, leading to significant inflammation and swelling. This inflammatory response can damage the seminiferous tubules, the structures within the testicles that produce sperm. Swelling can also increase pressure within the testicles, potentially restricting blood flow and damaging tissue.
Mumps orchitis can also disrupt the blood-testis barrier, a protective layer shielding developing sperm from the immune system. When compromised, the body’s immune cells may attack sperm antigens, reducing sperm count and quality. The inflammation can further impair fertility by affecting Leydig cells, which produce testosterone, a hormone necessary for sperm production.
Orchitis can affect one (unilateral) or both (bilateral) testicles. Unilateral orchitis is more common (60% to 70% of cases). While unilateral orchitis can temporarily reduce sperm count, it rarely causes complete sterility. Bilateral orchitis, affecting both testicles in 10% to 30% of cases, carries a higher risk, with infertility estimates ranging from 30% to 87%.
Preventing Mumps
Vaccination is the primary method for preventing mumps infection and its complications, including orchitis. The Measles, Mumps, and Rubella (MMR) vaccine is highly effective in preventing these diseases. The Centers for Disease Control and Prevention (CDC) recommends two doses of the MMR vaccine for children.
The first dose is administered between 12 and 15 months of age, and the second dose is given between 4 and 6 years of age. A second dose can be given earlier, with at least a 28-day interval between doses. Two doses of the MMR vaccine provide protection against mumps in approximately 86% to 88% of individuals.
Fertility Outlook After Mumps
Developing mumps orchitis does not automatically mean a man will become sterile. While some men experience a temporary decline in sperm production, many recover their fertility over time. The extent of recovery can depend on factors such as the severity of the infection and whether one or both testicles were affected.
Even with bilateral orchitis, where infertility risk is higher, complete sterility is not an inevitable outcome. Many men who experience mumps orchitis can still have children, sometimes with assisted reproductive technologies. If persistent concerns about fertility arise after a mumps infection, consulting a fertility specialist is a reasonable step for evaluation and guidance.