Flu shot didn't work? Maybe you had 'winter vomiting bug'

It's been a nasty flu season this year, and with it comes the inevitable complaints of people who got a flu shot but still got sick.

At the first sign of vomit many people complain: the flu vaccine didn't work!

But health officials say there's nothing wrong with the flu shot.

The clue to the confusion lies in the vomit.

The flu is a respiratory virus. The stomach flu is not really a flu at all — it's usually norovirus.

"It's the words we use to describe when we are sick that cause confusion," said Dr. Dee Hoyano with the Vancouver Island Health Authority.

In the U.K., stomach flu is called "winter vomiting bug," so that people do not equate  norovirus and influenza.

"It may help to describe the illness differently," said Hoyano.

• 'An epidemic': Flu outbreaks in 20 B.C. care facilities
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Most health care providers get vaccinated to protect co-workers and vulnerable patients.

The Vancouver Island Health authority staff competes to see which department can get the most staff vaccinated.

The winners get a trophy — a golden syringe.

How it works

The flu vaccine is distributed each year by the B.C. Centre for Disease Control. It is based on a formula recommended by the World Health Organization based on data from around the world.

"It's not a 100 per cent effective vaccine," said Hoyana. "It reduces risk."

But there's no guarantee of avoiding a different respiratory virus, and it does nothing to protect from the projectile vomiting that can be caused by norovirus.

It also takes a few weeks for full protection to kick in, so it's advised to get the shot early in the season. 

That is what Todd Wong of North Vancouver did in October.

The librarian assistant always gets his shot, as he often works with children and cares for elderly relatives.

He was thrilled the service was offered in a store.

"The people were friendly. We could talk about shopping for shoes — I even bought a hat!"

A few months later, he became the person at risk from flu.

Wong was celebrating Christmas with family when he felt some pain. He ended up undergoing open-heart surgery Dec. 26.

Now, as he recovers, he's at risk from anybody who did not get a flu shot.

"It's important if people come to visit me they have the flu shot, because I'm very vulnerable," said the 56-year-old, who appreciates people who make the effort, as his immune system needs the extra protection while he heals.

Norovirus or flu?

There really is no such thing as the stomach flu. 

Hoyano and other doctors call illnesses that involve vomiting norovirus or rotavirus, but there are a host of other viruses and bacteria that can cause gastroenteritis.

Norovirus comes on fast and brings diarrhea, vomiting, cramps but no sore throat, running nose or cough.

It's spread through the stool or vomit of infected persons, sometimes into food.

So the flu?

Influenza is a contagious viral infection of the upper airway (nose and throat) or respiratory system.

It causes fever, aches and runny noses.

It often occurs in epidemics and can be dangerous for vulnerable or immunocompromised people, as it puts them at risk of other infections such as viral or bacterial pneumonia, a lung infection.

It can last a week but usually does not cause vomiting in adults.

This year, the flu hit B.C. hard, especially in long-term care facilities with reported cases well above the 10-year historic average over December and into the first week of January.

It's hit seniors hardest this year. Twenty seniors' facilities in Victoria B.C., alone were dealing with active outbreaks on Jan. 18.

That has meant loose "lockdowns" of seniors in care centres in parts of the province where residents were encouraged to take their meals in their rooms until 72 hours passed since the last incidence of the flu.

There have been at least 15 confirmed deaths linked to flu in B.C., none of them children.