Officials said that Somerville's mayor, Joseph Curtatone, should not attend public events or work at his city hall office in the coming weeks due to a serious case of the virus shingles.
His office said he had recently been hospitalized for the shingles virus, the same virus that causes chickenpox.
The disease, which affects nearly one-third of adults in their lifetime, is not life-threatening, although it can be very painful.
In rare cases, the inner ear and the facial nerves are affected, as is the case with Curtatone, said his office.
Curtatone keeps in touch with the staff and should be able to resume her work remotely in the next few days.
"Although it is no longer contagious, because of the impact on his inner ear, which controls the balance, it is expected that the busy schedule of the mayor Curtatone be assigned for several weeks, "said his office. "Of course, if his recovery was faster, he would get back to his full schedule sooner."
The Curatone office said that when he resumed his public duties, he would probably wear an eye patch to protect his affected eye.
Shingles is the result of a reactivation of the dormant chickenpox virus, which remains in the body after previous cases. A varicella vaccine has been approved in the United States since 1995 and a shingles vaccine was approved in 2006.