Students and staff at an elementary school in Sherbrooke, Que. have been vaccinated against hepatitis A after eating fruit that has now been recalled over contamination fears.

More than 200 students and staff at l'Ecole du Sacré-Coeur took part in a health fair on April 7, blending fruit smoothies as they learned about healthy eating habits. What they didn’t realize was that the frozen fruit they used was potentially contaminated with the virus that causes hep A.

The Canadian Food Inspection Agency announced this week that the fruit brand, Nature's Touch brand Organic Berry Cherry Blend, sold exclusively at Costco, is being recalled.

The source of the contamination remains unknown.

On Wednesday, school officials notified the Eastern Townships public health board that the students and staff had eaten the berries.

They were informed that offering the hep A vaccine to those who may have eaten contaminated food can prevent illness if it is administered no later than 14 days after exposure.

With that 14-day window closing Thursday, the school decided to hold an emergency vaccination clinic.

Anyone who has already received a hep A or dual hep A/B vaccination, called Twinrix, is considered protected against infection and would not need a second vaccination.

So far, no one at the school has reported hepatitis A symptoms.

Costco originally said it would be offering free hep A vaccines until at least Friday to anyone who consumed the recalled fruit. But on Wednesday, the company updated a notice on their website to advise customers to contact their local public health department or physician to determine if they need the vaccine.

“Costco will also offer a hepatitis A vaccine, but supply and capacity is limited,” the company said.

“Please visit your local Costco Pharmacy for more information on vaccine availability.”

Hepatitis A is a viral liver disease that typically causes mild symptoms such as fever, nausea, vomiting, diarrhea, muscle aches, and yellowing in the whites of the eyes and the skin (known as jaundice).

Some who are infected show no symptoms at all, but the illness can become severe in the elderly and those with weakened immune systems.

The Public Health Agency of Canada says there have been 13 hepatitis A cases linked to the frozen fruit -- nine in Ontario, three in Quebec, and one in Newfoundland and Labrador.

All the individuals became sick in February and March. Five have had to be hospitalized.

The recalled fruit was sold by Costco locations in Eastern Canada between Dec. 11, 2015 and April 15, 2016 inclusively in 1.5 kg packages with Best Before dates up to and including March 16, 2018 (UPC code 8 73668 00179 1).

Costco locations in Eastern Canada also offered samples of the fruit, between March 22 and March 30, 2016 and at the Boucherville, Que. location on April 10.

Any customer who sampled the fruit in store is also affected by the recall.

Those who purchased the product are urged to throw it out or return it to the store where it was purchased. As well, anyone who ate the recalled product should see their health care provider immediately.