Signs abound indicating winter: frigid temperatures, gale warnings and snowfall.

Add to that confirmed cases of influenza, which total 14 so far this winter on the Vineyard. And many more have exhibited flu symptoms, said Carol Bardwell, chief nurse executive at the Martha’s Vineyard Hospital.

“There have been a lot of people coming into the emergency department with upper respiratory issues,” Ms. Bardwell said Wednesday afternoon.

The majority of the patients are 30 to 50-year-olds who have not been immunized, said Lena Crisco, director of the laboratory and infection control at the hospital.

So far this winter, there are fewer cases in all age groups compared with last winter, and children, who made up the majority of the confirmed samples last year, are just beginning to report to the hospital.

By the end of January of 2013, there were 86 confirmed cases of flu, most of them between the ages of five and 17.

Last year’s peak in flu cases may have encouraged more Islanders to get immunized this year, Ms. Crisco said. In addition, the vaccine was more comprehensive, she said.

The vaccine included the H1N1 variance, formerly known as swine flu, which is the strain present in all of the 14 cases this year.

Four of the five children who have tested positive were not immunized, Ms. Crisco said.

The 30 to 50-year-old age group tend to be more lax about immunization, Ms. Crisco said.

A limited supply of flu shots are available at Stop & Shop pharmacy in Edgartown and Vineyard Scripts in Vineyard Haven.

Shots are also available at the hospital emergency department and at offices of primary care physicians.