The official flu shot campaign starts today in B.C. and for the first time, health-care workers are required to get the vaccination or wear a mask near patients.

Provincial health officer Dr. Perry Kendall says in the past, less than half of the province's health-care workers have been voluntarily vaccinated.

"We have really good evidence that health-care workers do get influenza," he said.

"They can be infectious before they show symptoms, so even if they're really good about staying home once they start to feel ill and cough, they've probably been spreading the virus for 24 hours before that."

But the B.C. Hospital Employees' Union hopes the province will revoke the policy. The union says it encourages employees to get the flu shot but feels it should be a choice, not mandatory.

According to Immunize B.C., hundreds of people die from influenza or related complications every year.

Symptoms include fever, headache, muscle pain, runny nose, sore throat, extreme tiredness, and cough. Fever and other symptoms can usually last seven to 10 days, with the cough and weakness lasting up to two more weeks

Influenza in people 65 years of age and older, and in other high risk groups, can lead to more serious health concerns.