4 Northeastern graduate students diagnosed with chicken pox last week

Four Northeastern University graduate students were diagnosed with chickenpox last week, according to an email sent to students by the school’s health and counseling services.

The students are “are being treated for the disease and are taking all necessary precautions,” including isolation, the university said. The students live off-campus in the Boston area.

The Boston Public Health Commission (BPHC) has determined that anyone who has not been fully vaccinated for chickenpox, or has not previously contracted it, must isolate if they are exposed to someone who has been infected, the university said.

The isolation period begins eight days after exposure and ends after 21 days.

Chickenpox is caused by the varicella virus and can spread from person to person by direct contact with fluids from a blistering chicken pox rash or through the air when a person with chickenpox coughs or sneezes, according to the Center for Disease Control and Prevention (CDC).

Chickenpox can spread from one to two days before the rash starts until the rash crusts over, according to the CDC. It can take up to 21 days for an exposed person to develop symptoms, the CDC says.

People are protected from chickenpox if they have already contracted the disease or have received two doses of the varicella vaccine, according to the CDC.

Massachusetts law requires all university students to provide documentation of vaccination against varicella, according to Northeastern’s health guidelines. The criteria requires two doses or positive antibody titers.

“Protection from chickenpox is especially important in settings where the infection might spread quickly, such as schools and colleges,” said Massachusetts Department of Public Health spokesperson Katheleen Conti.

The disease can be high risk or even life-threatening for adolescents, people who are pregnant, infants, and people with weakened immune systems, according to the CDC.

Although hospitalizations and deaths are rare today due to vaccines, deaths from chickenpox can still occur in healthy adults and children if they are unvaccinated, the CDC says. Many healthy adults who have died from chickenpox contracted the disease from their unvaccinated children.

“People who have recently been exposed to chickenpox and are susceptible to infection, those who are unvaccinated and have never had chickenpox, should receive vaccination as soon as possible,” Conti said.

The US became the first country to include the chickenpox vaccine as part of routine childhood immunizations in 1995, according to the CDC. Since then, cases have declined by more than 97 percent and there are fewer than 1,400 hospitalizations and 30 deaths each year, the CDC says.

Students who develop symptoms of chickenpox, including “a rash on your face, stomach, chest, or back, with fever, tiredness, or general discomfort” should immediately contact their healthcare provider and isolate until their symptoms are reviewed by a healthcare provider, the university said in its email.

Sabrina Lam can be reached at sabrina.lam@globe.com.