But after dozens of people in British Columbia recently fell ill after eating raw oysters, many may be wondering if they should skip the shellfish this year to keep safe.

The BC Centre for Disease Control on Thursday posted a warning that between Nov. 1 and Dec. 18, 64 cases of a “norovirus-like” gastrointestinal illnesses were reported in the province, after people ate raw oysters from restaurants and local retailers.

Some people went to emergency departments with symptoms of diarrhea, vomiting, or stomach pain, but there have been no hospital admissions reported, health authorities said.

“We are reminding everyone about the risks of consuming raw or undercooked oysters. Cooking destroys viruses and bacteria and decreases the risk of illness,” the BC Centers for Disease Control said in a social media post.

Noroviruses are a group of viruses that cause stomach issues like diarrhea and vomiting. They spread easily through contact with infected people’s stool or vomit.

Some foods can also get contaminated right from the start — like oysters, which can pick up the virus from sewage in the water before they’re harvested, according to the Public Health Agency of Canada (PHAC).

2:06 Warning about eating raw B.C. oysters

Sylvain Charlebois, director of Dalhousie University’s Agrifood Analytics Lab, said because oysters may be a holiday tradition for some, it’s important to stay vigilant when consuming them.

“The thing about the holidays is that people do treat themselves to some oysters, and their bodies may not be accustomed to dealing with some of the viruses that they ingest,” Charlebois said.

“During the holidays, you’re often more tired and drinking more than usual, so getting sick with a virus tends to hit harder at this time of year,” he said, adding that when it comes to norovirus, children, older adults and pregnant people are especially vulnerable.

So before you grab that oyster, here’s a bit more of what you need to know about oysters, bacteria and viruses.

Raw oysters can be a risky holiday treat as they may contain harmful bacteria, viruses and toxins that can lead to foodborne illnesses, explained Keith Warriner, a food safety professor at the University of Guelph.

Oysters feed by filtering water and microorganisms, which can lead to toxins accumulating in their tissues, he said, adding that it’s not just oysters — any bivalve shellfish (like mussels and clams) can absorb harmful substances from the water they filter.

“What happens is that when you get polluted water, like sewage discharge, septic… the oysters concentrate these pathogens. Norovirus is one, and the other famous one is vibrio,” Warruner said.

“Once they get in there, it is difficult to remove. There is a process called de-puration when you get these shellfish in these tanks and they try and flush them through with water. Sometimes they use sanitizers, but they have to keep the oysters alive, as you usually don’t cook oysters.”

So, Warriner said, what happens in the sea can end up on your plate and make you sick, especially when it comes to norovirus, which is difficult to kill and highly contagious.

The good news is you can eliminate the norovirus by cooking the oysters if you choose not to eat them raw.

1:07 U.S. woman dies from flesh-eating bug after eating raw oysters

Although B.C. health officials linked the latest outbreak to “norovirus-like” gastroenteritis, Warriner said he wouldn’t be surprised if vibrio was also involved.

Vibrio is a type of bacteria commonly found in warm coastal waters and is often linked to shellfish, like oysters. It thrives in warmer waters, especially when temperatures rise above 15 C.

With rising ocean temperatures due to climate change, vibrio can multiply more quickly in the water where oysters are harvested, according to PHAC.

“Vibrio used to be this sort of thing you would find in the Gulf of Mexico where the waters of warm, now they’re recovering it from the coasts of  B.C. and Nova Scotia,” Warriner said.

If someone ingests the bacteria, symptoms may include watery or bloody diarrhea, stomach cramps, nausea, vomiting, fever, and headache, he said.

If you’re planning to enjoy oysters or any other raw shellfish during the holidays, Charlebois advises finding out where they come from.

“That’s the most important thing is to know the source… is to actually deal with a trustworthy source. Unfortunately, some oyster farms once in a while are exposed to some contaminants. So it’s important consumers know where their oysters are coming from,” he said.

The risk is lower if the oysters are part of a short distribution chain, as opposed to those that have traveled long distances, which may increase the risk to ensure their freshness, Charlebois said.

B.C., New Brunswick, Prince Edward Island and Nova Scotia are prime locations for farmed oysters in Canada, though they are also imported from countries like Thailand.

0:33 Warning from Health Canada about B.C. oysters

Charlebois added that although oyster contamination can happen, it’s not “overly common.”

“But you got you have to be careful. Obviously, norovirus is a really contagious virus. You want to be extremely careful, especially with people with a compromised immune system, seniors, pregnant women and children.”

Since eating oysters can always pose a risk of contamination, Warriner suggests that you can skip them altogether if you’d prefer.

“If you said to me which area makes the safest oysters, I couldn’t even tell you, because every single place I know that produces oysters has some sort of issue with water quality,” he added.

Egg prices are rising once more as a lingering outbreak of bird flu coincides with the high demand of the holiday baking season.

But prices are still far from the recent peak they reached almost two years ago. And the American Egg Board, a trade group, says egg shortages at grocery stores have been isolated and temporary so far.

“Those are being rapidly corrected, sometimes within a day,” said Emily Metz, the Egg Board’s president and chief executive officer.

The average price for a dozen eggs in U.S. cities was $3.37 in October, according to the Bureau of Labor Statistics. That was down slightly from September, and down significantly from January 2023, when the average price soared to $4.82. But it was up 63 per cent from October 2023, when a dozen eggs cost an average of $2.07.

Sometimes, supermarkets may be to blame for price spikes. During testimony in August in the Federal Trade Commission’s case seeking to block Kroger’s merger with Albertsons, Kroger’s senior director for pricing acknowledged that the company has raised the cost of milk and eggs beyond the levels of inflation.

But there are other factors behind the price increases. Metz said the egg industry sees its highest demand in November and December, for example.

“You can’t have your holiday baking, your pumpkin pie, your stuffing, without eggs,” she said.

Avian influenza is another big reason for the higher prices. The current bird flu outbreak that began in February 2022 has led to the slaughter of more than 111 million birds, mostly egg-laying chickens. Anytime the virus is found, every bird on a farm is killed to limit the spread of the disease.

3:53 B.C. bird flu case remains a mystery

More than six million birds have been slaughtered just this month because of bird flu. They were a relatively small part of the total U.S. egg-laying flock of 377 million chickens. Still, the flock is down about three per cent over the past year, contributing to a four per cent drop in egg production, according to the U.S. Department of Agriculture.

The latest wave of bird flu is scrambling supplies of cage-free eggs because California has been among the hardest hit states. California, Nevada, Washington and Oregon all require eggs sold in their states to be cage-free.

“We’re having to move eggs from other areas of the country that are producing cage-free to cover that low supply in those states, because those states only allow for cage-free eggs to be sold,” Metz said.

Cage-free requirements are set to go into effect in Arizona, Colorado and Michigan next year and in Rhode Island and Utah in 2030.

Demand for such specialty eggs may also be contributing to avian flu, which is spread through the droppings of wild birds as they migrate past farms. Allowing chickens to roam more freely puts them at greater risk, said Chad Hart, a professor and agricultural economist at Iowa State University.

“It’s really hard to control that interaction between domesticated birds and wild birds,” Hart said. “Some of those vectors have been opened up because we’re asking the egg industry to produce in ways that we didn’t ask them to before.”

1:55 Nearly seven million birds culled in B.C.’s Fraser Valley due to avian flu

Metz said climate change and extreme weather are also blowing some wild birds off course.

“We have birds that have been displaced by hurricanes, by wildfires, and those birds are now circulating in areas that they otherwise might not circulate or at times of the year that they otherwise may not be circulating,” she said. “And those are all new variables that our farmers are having to deal with.”

Hart said the egg industry is trying to rebuild the flock, but that also can limit supplies, since farmers have to hold back some eggs to hatch into new chickens.

Still, there is some good news on U.S. poultry farms. The price of chicken feed — which represents 70 per cent of a farmer’s costs — has fallen significantly after doubling between 2020 and 2022, Hart said.

The United States reported its first severe human case of bird flu on Wednesday, involving a Louisiana resident, as California declared a state of emergency to address the escalating outbreak.

The Louisiana patient was hospitalized in critical condition after suspected contact with an infected backyard flock, according to the U.S. Centers for Disease Control and Prevention (CDC). The case, confirmed on Dec. 13, is the first in the country linked to severe illness from the avian flu.

“This is the first case of H5N1 bird flu in the U.S. that has been linked to exposure to a backyard flock,” the CDC said in a statement.

As the CDC confirmed the bird flu case, California Gov. Gavin Newsom declared a state of emergency on Wednesday, describing it as a precautionary measure to help contain the virus’s spread.

To date, no person-to-person spread of the virus has been detected in California and nearly all infected individuals had exposure to infected cattle, the statement read.

“This proclamation is a targeted action to ensure government agencies have the resources and flexibility they need to respond quickly to this outbreak. Building on California’s testing and monitoring system — the largest in the nation — we are committed to further protecting public health, supporting our agriculture industry, and ensuring that Californians have access to accurate, up-to-date information. While the risk to the public remains low, we will continue to take all necessary steps to prevent the spread of this virus,” Newsom said in a statement.

5:09 Bird Flu Adaptation: What it means for humans

Since April, there have been a total of 61 reported human cases of H5N1 bird flu reported in the U.S. The virus has spread in 16 states among dairy cattle, following its first confirmed detection in Texas and Kansas in March.

The recent bird flu case in Louisiana highlights the ongoing spread of the H5N1 avian influenza virus, with genome data showing the virus belongs to the D1.1 genotype, the CDC said. This genotype has been linked to recent detections in wild birds and poultry across the U.S., as well as human cases in British Columbia.

On Nov. 3, the Public Health Agency of Canada confirmed that a teenager had contracted a human case of bird flu, caused by the influenza A (H5N1) virus. It marked the first domestically acquired human case of bird flu in Canada. As of Nov. 25, the province reported that the teen remains in critical condition.

Despite this latest case in Louisiana, the CDC maintains that the overall risk to public health from H5N1 remains low. In Canada, the risk also remains low.

While there have been several outbreaks of bird flu on dairy farms in multiple states, the virus has not been detected on dairy farms anywhere in Canada.

Human-to-human transmission of H5N1 — a strain of highly pathogenic avian influenza — is rare with no evidence of sustained transmission, experts say. The majority of human cases in the U.S. and around the world have been due to contact with infected birds, farm animals or wildlife.

— With files from the Canadian Press and Reuters

However, recent comments — including from U.S. president-elect Donald Trump’s pick for health secretary, Robert F. Kennedy Jr. and his lawyer — are amplifying claims questioning the safety of vaccines for measles, mumps and rubella, as well as polio.

Both have been used safely for decades around the world by millions of people.

Aaron Siri, a lawyer advising Robert F. Kennedy Jr., in 2022 asked the Food and Drug Administration (FDA) to revoke its approval of the current polio vaccine, but the petition gained renewed attention over recent weeks after Kennedy was named as Trump’s health secretary pick.

In the petition letter, Siri urged the FDA to withdraw or suspend the polio vaccine, alleging that its original clinical trials lacked control groups and monitored long-term safety, thereby failing to meet federal safety standards

However, the polio vaccine he mentions, IPOL, has undergone extensive clinical trials, including control groups. Regulatory agencies such as the FDA have approved the vaccine based on robust evidence.

Kennedy is also a vaccine skeptic, recently saying that he may investigate vaccines he claims are linked to autism, a long-debunked theory.

1:21 ‘Iron Lung Man’ dies at 78 after more than 70 years of paralysis from polio

His comments, along with the ongoing spread of vaccine skepticism, have sparked increased interest on Google. This surge in curiosity is reflected in the rise of breakout Google search terms, including queries like “What is polio?”, “Polio vaccine approval,” and “Does polio still exist?”.

Amid this surge in curiosity, Trump weighed in on the issue, telling reporters on Monday, “Nothing’s going to happen quickly,” when it comes to the polio vaccine.

“Bobby’s a very rational guy, you’re not going to lose the polio vaccine,” he told reporters. “I have friends that were very much affected, and they are still in not good shape because of it.”

As vaccine rhetoric from the U.S. continues to spread, Dr. Christopher Labos, a Montreal-based cardiologist and epidemiologist, fears that growing vaccine hesitancy could lead to a resurgence of polio.

“The more doubt introduced into people’s minds about the effectiveness and safety of the vaccine, the more vaccine rates start to dip. And it’s not going to take that much to bring us below the critical threshold where we start seeing more and more polio outbreaks either in the U.S. or in this country,” he said.

“If we start getting back to the days of the sustained spread of community spread of polio, we are going to see more people getting sick. We’re going to see more children paralyzed, we’re going to see deaths,” Labos added.

Polio is a highly contagious viral disease caused by the poliovirus.

It primarily affects children under the age of five but can also impact adults. The virus spreads through person-to-person contact, often via contaminated food, water, or surfaces, and it can attack the nervous system, according to the World Health Organization (WHO).

While many people infected with the virus experience mild or no symptoms, others develop more serious complications, including permanent disability. In severe cases, polio can lead to paralysis, muscle weakness, and in some cases, death.

Throughout the early 20th century, polio outbreaks began to happen more regularly, especially in summer months, with cities seeing large numbers of cases, according to the U.S. Centers for Disease Control and Prevention (CDC). Little was known about how the disease spread, leading to closed pools in summer and empty playgrounds as parents tried to protect their children from falling ill.

5:25 Canada could test wastewater for polio ‘should that need arise’: Tam

And many children who contracted the disease faced severe, long-term consequences, including paralysis and the need for life-saving devices like the iron lung to assist with breathing.

But, once a widespread and devastating disease, polio has seen a 99 per cent drop in cases worldwide since 1988, thanks to the global push for vaccination and eradication efforts.

Since 1994, Canada has been free from the virus.

As of now, the poliovirus remains endemic in just two countries: Afghanistan and Pakistan.

“Until poliovirus transmission is interrupted in these countries, all countries remain at risk of importation of polio, especially vulnerable countries with weak public health and immunization services and travel or trade links to endemic countries,” according to the Global Polio Eradication Initiative.

There is no cure for polio; it can only be prevented.

The first successful vaccine was developed in the 1950s by Jonas Salk, whose inactivated polio vaccine (IPV) was introduced to the public in 1955 and became a cornerstone in the global effort to eradicate the disease.

The polio vaccine, given multiple times, can protect a child for life.

There are two types of vaccines available: the oral polio vaccine (OPV) and the IPV.

Both are safe and effective, and they are used in different combinations worldwide, depending on local epidemiological factors, to provide the best possible protection to populations, the Global Polio Eradication Initiative reports.

Polio is part of the routine vaccine schedule in Canada and is given to infants as part of a combination vaccine. It’s called DTaP-IPV-Hib-HB and protects against diphtheria, tetanus, pertussis (whooping cough), polio, Haemophilus influenzae type b (Hib) and hepatitis B.

Like the IPOL vaccine in the U.S., it is also an IPV. The vaccine is typically administered in multiple doses during the first few years of life to ensure long-lasting protection against the disease.

2:20 COVID-19 parallels: polio disaster helped shape vaccine safety in 1950s

According to the CDC, the polio vaccine protects against severe disease caused by poliovirus in almost everyone who has received all the recommended doses. Two doses of IPV provide at least 90 per cent protection. Three doses of IPV provide at least 99 per cent protection. The most common side effect is a sore arm after the shot.

“The injected vaccine does not carry any significant side effects,”  Dr. Peter Salk, son of Jonas Salk, told Global News.

“On a very rare occasion, somebody may have an allergy to one of the components, one of the antibiotics that is used to keep things sterile. Otherwise … the medicine is really a safe vaccine,” said Salk.

Last week, U.S. Senate Republican leader Mitch McConnell, who had polio as a child, said any of president-elect Donald Trump’s nominees seeking Senate confirmation should “steer clear” of efforts to discredit the polio vaccine.

“Efforts to undermine public confidence in proven cures are not just uninformed — they’re dangerous,” McConnell said in a statement Friday.

Labos and Salk agreed.

Salk, who is a professor in the department of infectious diseases and microbiology at the University of Pittsburgh School of Public Health, explained that the public’s fear of serious diseases has diminished over time, as the terrifying effects of polio have faded from memory.

“Polio, whooping cough…these are not prevalent at this point because of vaccines. And back in the 1950s, parents were terrified of polio. Now the fear of infectious disease hasn’t been at a high pitch and people are susceptible to the notion that ‘why do want to continue to vaccinate our children? ‘”

“We want to continue to vaccinate children because diseases can come back, as it has with measles and with whooping cough,” he said.

Countries like Canada and the U.S. eliminated polio through vaccination efforts, Labos said, and abandoning these efforts could lead to the virus’s resurgence.

6:19 NS Woman Shares Her Experience Living with Post-Polio Syndrome

Even if the polio vaccine remains widely available, he said, if those in charge convince enough people not to get vaccinated, polio will make a comeback.

“I am a little bit worried because this whole anti-vaccine rhetoric has been gaining momentum in recent years, and gained legitimacy by the fact that RFK might become the head of HHS. And it is very, very problematic because we know vaccines work,” Labos said.

Cases of polio still appear in Canada due to international travel, Labos explained. People may contract the virus abroad and bring it back, where it can spread in small pockets, particularly in areas with unvaccinated individuals.

However, these outbreaks are manageable because most people are vaccinated, providing a level of protection.

He cautioned that if vaccination rates drop below a critical threshold, the population won’t have enough immunity to prevent widespread transmission, and polio could become a constant presence.

“If the number of vaccinated people starts getting lower below 80 per cent, there is a very real chance that we’re going to start to see community spread of polio again,” Labos warned.

— With files from Global News’ Amanda Connolly and the Associated Press