I saw an almost 2-year-old child this morning who’d been given all his vaccinations. He’d had fever since last night, and this morning his mother noticed that the right side of his face and the area under his lower jaw were swollen. My examination wasn’t conclusive – I wasn’t entirely certain that the infection was in the parotid salivary gland; it might also be a bacterial infection of the surrounding lymph nodes (acute lymphadenitis). But as I’d heard that mumps is now circulating in Borough Park among the ultra-Orthodox Jews – the very same location and demographic which had a measles epidemic a few short months ago, and whose relatives are among the population I serve, it was definitely worth checking to see if mumps had arrived in our area as well.
A few short phone calls (to our local infectious disease consult, the Health Ministry’s epidemiology dept. and the virology lab in Tel Hashomer hospital near Tel Aviv) confirmed that there have indeed been cases of mumps in our area, and that we should regard this little boy as a suspected case, quarantine him, and check if he has an acute antibody reaction (IgM antibodies) to the mumps virus. I’m also giving him antibiotics on the chance that it’s bacterial lymphadenitis and not a viral infection, however.
Of the 3 viral infections the MMR vaccinates against, the mumps vaccine is the least effective – the vaccine strain most often used in the west used to vaccinate against mumps (Jeryl Lynn) is about 75-90% effective in a highly vaccinated population, possibly lower in an epidemic situation. Hence it’s not surprising that most of the people who contacted mumps in the New York outbreak were themselves vaccinated (for further explanation of why this happens, see here). That’s far from saying it’s worthless: While complications are rare in young children, it was a leading cause of deafness (uni- and bilateral) in children before vaccination programs began; in fact, Japanese researchers – in Japan, mumps is endemic,as the vaccine is optional – suspect that it’s more common than previously thought. Mumps is also a cause of sterility in young men acquiring it, and rarely may also cause pancreatitis and encephalitis – severe and often fatal diseases.
Let’s keep our fingers crossed that this little boy doesn’t have it.