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Coronavirus in Wuhan, China: Why it’s hard to know how bad the virus outbreak will be – Vox.com

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In the past 24 hours, the number of cases of the new coronavirus originating in Wuhan, China, nearly doubled to more than 4,400. Since the outbreak was announced on December 31, the virus has taken the lives of 107 people.

Less than four weeks into the outbreak, fear about how bad this could get is spreading faster than the virus. And with good reason.

While the vast majority of cases and deaths are occurring on mainland China, 2019-nCoV has already made its way to at least a dozen other countries, including the US, Germany, and Canada. People are buying face masks. Markets are on edge. Cities and countries are responding with mass quarantines and travel bans. The whole thing feels a lot like the 2011 pandemic film, Contagion.

So how big could the outbreak get? Is this the next pandemic — a disease that spreads globally?

Answering this requires knowing the answers to two other questions: How easily does the 2019-nCoV spread from person to person, and how deadly is the virus? At the moment, scientists only have informed guesses, which are likely to solidify in the coming weeks and months. But what we know so far is instructive.

With every disease outbreak, epidemiologists try to figure out how far — and how fast — a virus is likely to spread through a population. To do that, they use the basic reproduction number, called the “R naught,” or R0.

Most simply, the figure refers to how many other people one sick person is likely to infect on average in a group that’s susceptible to the disease (meaning they don’t already have immunity from a vaccine or fighting off the disease before).

The R0 is super important in the context of public health because it foretells how big an outbreak will be. The higher the number, the greater likelihood a lot of people will fall sick.

Measles, the most contagious virus researchers know about, can linger in the air of a room and sicken people up to two hours after an infected person who coughed or sneezed there has left. If people exposed to the virus aren’t vaccinated, measles’ R0 can be as high as 18.

Ebola is much less efficient: Its R0 is typically just 2, since most infected individuals die before they can pass the virus to someone else.

Now, here’s a big caveat: The R0 is not “something that is fixed,” said Marion Koopmans, who studies emerging infectious diseases and heads the department of virology at Erasmus Medical Center in Rotterdam, Netherlands.

Diseases behave differently in different environments, depending on factors like population density and susceptibility to a disease in a population. For example, in the case of norovirus — that nasty and highly contagious bug infamous for causing outbreaks of stomach flu on cruise ships — the R0 estimates vary depending on whether the outbreak is contained in one place (like a hospital) or spread more widely.

Some individuals are also more contagious — and have a higher R0 — than others, because of their viral load, for example, or the airflow in the building where they’re sick. (The folks who are especially contagious are known as “super-spreaders.”)

With these caveats in mind, here’s what we know about the R0 for the new coronavirus. According to a preliminary estimate from WHO, at the moment, each individual infected with 2019-nCoV has transmitted the virus to an average of 1.4 to 2.5 others. That would make 2019-nCoV less contagious than SARS, which had an R0 of 3, but more contagious than seasonal flu.

That’s just the WHO’s word. There are literally dozens of estimates about 2019-nCoV’s R0 floating around, from research groups around the world. And different research groups use different statistical models, assumptions, and data to plug into their models.

In all, I found a broad range of R0 estimates — from 1.4 to 5.47 — being put forward.

If one narrows the estimates to some of the world’s top epidemiological modeling labs — like Maia Majumder’s at Boston Children’s Hospital or Christian Althaus’s at the University of Bern or Jon Read’s at Lancaster — the range looks a lot smaller: 2 to 3.8. That would make the new coronavirus at least as contagious as seasonal flu and potentially more contagious than SARS.

“Given the recent emergence of this disease, the very limited data available, and the very different methods employed for estimation, the consistency of these estimates is remarkable,” Toronto epidemiologist David Fisman told Vox over email.

Still, it’s early days. “It’s difficult or impossible to get an accurate R0 at the beginning of an epidemic,” said Daniel Lucey, an infectious diseases physician and adjunct professor of infectious diseases at Georgetown University Medical Center. We don’t yet know exactly when or how the outbreak began, where it’s spread, or how many people are sick. Only in the coming weeks — as researchers gather more data on how the virus is moving — will they be able to refine the R0.

For now, though, there are a couple of things they can say. “Because it’s above 1, that means we know it can cause sustained transmission in humans,” said Maia Majumder, faculty at Boston Children’s Hospital’s Computational Health Informatics Program. An R0 below one means an outbreak is likely to burn out. But, “Just because the number is high [like SARS’s R0 or the upper end of the current 2019-nCoV estimate] doesn’t mean it’s going to cause a massive pandemic.”

“We do have good examples of high reproductive number diseases like SARS,” Majumder added. “It had no vaccine, no specific care approach, and we still managed to get the situation under control.” That’s because the R0 can’t account for all the interventions public health officials put in place, like infection control measures in hospitals or antivirals.

So even as the R0 evolves in the coming days, and even if it gets higher, that doesn’t necessarily mean the outbreak will grow into a pandemic.

Next to the R0, the other most important way to understand how bad an outbreak could get is the case fatality rate, or CFR. In simple terms, it’s the proportion of deaths a disease causes within a group of people who have the disease.

Here, too, there are problems with arriving at a solid estimate at the moment. To have a firm understanding of the CFR, you need to know how many people in a population have the virus, and among those, how many die. And early on in outbreaks, we don’t often know.

Visualization of 2019-nCoV with Transmission Electron Microscopy.
NEJM

That’s because the sickest are usually the ones who show up at doctor’s offices and in hospitals. But there may be hundreds or thousands of others with the virus who never show symptoms, or never bother going to see a doctor because they’re not very sick. (That’s why the CFR can often look much worse in the early days of an outbreak.)

Getting an accurate CFR would require a survey of the Chinese population, to find out who has antibodies for the virus, said Majumder, including the folks who didn’t even know they had it. That’ll give experts the denominator — the real case toll — in the CFR equation. “Until we’ve done [that] — and I’m sure it’ll happen sometime in the future — there are going to be some people that have mild infections or are asymptomatic infections that we’re not picking up.” Plus, there are many people with the infection in limbo in hospitals, who may or may not survive the pneumonia that comes with it.

So while there’s a great hunger for clarity about how bad the outbreak will become, frustratingly at this stage, researchers need time to work that out.

In the meantime, there’s a tendency for speculation to fill the vacuum. For example, there’s a lot of guesswork about the case fatality rate for the new virus. A bunch of people are taking the number of deaths this disease has caused, and dividing that by the number of cases diagnosed, Majumder said. (As of this writing, that’d be 106 divided by 4,629 — for a CFR of 2 percent, making this virus less deadly than SARS or whooping cough and more deadly than the seasonal flu.)

But again, it’ll be a while before we know the true number of cases and have a clear picture of the deaths.

Here is what we know for sure: While more than 100 people have died in this outbreak so far, and seasonal flu kills between 250,000 and 650,000 people annually. For most people, “you’re probably more likely to be catching flu than you are to be getting coronavirus,” said Devi Sridhar, chair in global public health at the University of Edinburgh.

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Health Canada approves updated Novavax COVID-19 vaccine

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Health Canada has authorized Novavax’s updated COVID-19 vaccine that protects against currently circulating variants of the virus.

The protein-based vaccine, called Nuvaxovid, has been reformulated to target the JN.1 subvariant of Omicron.

It will replace the previous version of the vaccine, which targeted the XBB.1.5 subvariant of Omicron.

Health Canada recently asked provinces and territories to get rid of their older COVID-19 vaccines to ensure the most current vaccine will be used during this fall’s respiratory virus season.

Earlier this week, Health Canada approved Moderna’s updated mRNA COVID vaccine.

It is still reviewing Pfizer’s updated mRNA vaccine, with a decision expected soon.

This report by The Canadian Press was first published Sept. 19, 2024.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

Note to readers: This is a corrected story. A previous version erroneously described the Novavax vaccine as an mRNA shot.

The Canadian Press. All rights reserved.

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Health Canada approves updated Moderna COVID-19 vaccine

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TORONTO – Health Canada has authorized Moderna’s updated COVID-19 vaccine that protects against currently circulating variants of the virus.

The mRNA vaccine, called Spikevax, has been reformulated to target the KP.2 subvariant of Omicron.

It will replace the previous version of the vaccine that was released a year ago, which targeted the XBB.1.5 subvariant of Omicron.

Health Canada recently asked provinces and territories to get rid of their older COVID-19 vaccines to ensure the most current vaccine will be used during this fall’s respiratory virus season.

Health Canada is also reviewing two other updated COVID-19 vaccines but has not yet authorized them.

They are Pfizer’s Comirnaty, which is also an mRNA vaccine, as well as Novavax’s protein-based vaccine.

This report by The Canadian Press was first published Sept. 17, 2024.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

The Canadian Press. All rights reserved.

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These people say they got listeria after drinking recalled plant-based milks

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TORONTO – Sanniah Jabeen holds a sonogram of the unborn baby she lost after contracting listeria last December. Beneath, it says “love at first sight.”

Jabeen says she believes she and her baby were poisoned by a listeria outbreak linked to some plant-based milks and wants answers. An investigation continues into the recall declared July 8 of several Silk and Great Value plant-based beverages.

“I don’t even have the words. I’m still processing that,” Jabeen says of her loss. She was 18 weeks pregnant when she went into preterm labour.

The first infection linked to the recall was traced back to August 2023. One year later on Aug. 12, 2024, the Public Health Agency of Canada said three people had died and 20 were infected.

The number of cases is likely much higher, says Lawrence Goodridge, Canada Research Chair in foodborne pathogen dynamics at the University of Guelph: “For every person known, generally speaking, there’s typically 20 to 25 or maybe 30 people that are unknown.”

The case count has remained unchanged over the last month, but the Public Health Agency of Canada says it won’t declare the outbreak over until early October because of listeria’s 70-day incubation period and the reporting delays that accompany it.

Danone Canada’s head of communications said in an email Wednesday that the company is still investigating the “root cause” of the outbreak, which has been linked to a production line at a Pickering, Ont., packaging facility.

Pregnant people, adults over 60, and those with weakened immune systems are most at risk of becoming sick with severe listeriosis. If the infection spreads to an unborn baby, Health Canada says it can cause miscarriage, stillbirth, premature birth or life-threatening illness in a newborn.

The Canadian Press spoke to 10 people, from the parents of a toddler to an 89-year-old senior, who say they became sick with listeria after drinking from cartons of plant-based milk stamped with the recalled product code. Here’s a look at some of their experiences.

Sanniah Jabeen, 32, Toronto

Jabeen says she regularly drank Silk oat and almond milk in smoothies while pregnant, and began vomiting seven times a day and shivering at night in December 2023. She had “the worst headache of (her) life” when she went to the emergency room on Dec. 15.

“I just wasn’t functioning like a normal human being,” Jabeen says.

Told she was dehydrated, Jabeen was given fluids and a blood test and sent home. Four days later, she returned to hospital.

“They told me that since you’re 18 weeks, there’s nothing you can do to save your baby,” says Jabeen, who moved to Toronto from Pakistan five years ago.

Jabeen later learned she had listeriosis and an autopsy revealed her baby was infected, too.

“It broke my heart to read that report because I was just imagining my baby drinking poisoned amniotic fluid inside of me. The womb is a place where your baby is supposed to be the safest,” Jabeen said.

Jabeen’s case is likely not included in PHAC’s count. Jabeen says she was called by Health Canada and asked what dairy and fresh produce she ate – foods more commonly associated with listeria – but not asked about plant-based beverages.

She’s pregnant again, and is due in several months. At first, she was scared to eat, not knowing what caused the infection during her last pregnancy.

“Ever since I learned about the almond, oat milk situation, I’ve been feeling a bit better knowing that it wasn’t something that I did. It was something else that caused it. It wasn’t my fault,” Jabeen said.

She’s since joined a proposed class action lawsuit launched by LPC Avocates against the manufacturers and sellers of Silk and Great Value plant-based beverages. The lawsuit has not yet been certified by a judge.

Natalie Grant and her seven year-old daughter, Bowmanville, Ont.

Natalie Grant says she was in a hospital waiting room when she saw a television news report about the recall. She wondered if the dark chocolate almond milk her daughter drank daily was contaminated.

She had brought the girl to hospital because she was vomiting every half hour, constantly on the toilet with diarrhea, and had severe pain in her abdomen.

“I’m definitely thinking that this is a pretty solid chance that she’s got listeria at this point because I knew she had all the symptoms,” Grant says of seeing the news report.

Once her daughter could hold fluids, they went home and Grant cross-checked the recalled product code – 7825 – with the one on her carton. They matched.

“I called the emerg and I said I’m pretty confident she’s been exposed,” Grant said. She was told to return to the hospital if her daughter’s symptoms worsened. An hour and a half later, her fever spiked, the vomiting returned, her face flushed and her energy plummeted.

Grant says they were sent to a hospital in Ajax, Ont. and stayed two weeks while her daughter received antibiotics four times a day until she was discharged July 23.

“Knowing that my little one was just so affected and how it affected us as a family alone, there’s a bitterness left behind,” Grant said. She’s also joined the proposed class action.

Thelma Feldman, 89, Toronto

Thelma Feldman says she regularly taught yoga to friends in her condo building before getting sickened by listeria on July 2. Now, she has a walker and her body aches. She has headaches and digestive problems.

“I’m kind of depressed,” she says.

“It’s caused me a lot of physical and emotional pain.”

Much of the early days of her illness are a blur. She knows she boarded an ambulance with profuse diarrhea on July 2 and spent five days at North York General Hospital. Afterwards, she remembers Health Canada officials entering her apartment and removing Silk almond milk from her fridge, and volunteers from a community organization giving her sponge baths.

“At my age, 89, I’m not a kid anymore and healing takes longer,” Feldman says.

“I don’t even feel like being with people. I just sit at home.”

Jasmine Jiles and three-year-old Max, Kahnawake Mohawk Territory, Que.

Jasmine Jiles says her three-year-old son Max came down with flu-like symptoms and cradled his ears in what she interpreted as a sign of pain, like the one pounding in her own head, around early July.

When Jiles heard about the recall soon after, she called Danone Canada, the plant-based milk manufacturer, to find out if their Silk coconut milk was in the contaminated batch. It was, she says.

“My son is very small, he’s very young, so I asked what we do in terms of overall monitoring and she said someone from the company would get in touch within 24 to 48 hours,” Jiles says from a First Nations reserve near Montreal.

“I never got a call back. I never got an email”

At home, her son’s fever broke after three days, but gas pains stuck with him, she says. It took a couple weeks for him to get back to normal.

“In hindsight, I should have taken him (to the hospital) but we just tried to see if we could nurse him at home because wait times are pretty extreme,” Jiles says, “and I don’t have child care at the moment.”

Joseph Desmond, 50, Sydney, N.S.

Joseph Desmond says he suffered a seizure and fell off his sofa on July 9. He went to the emergency room, where they ran an electroencephalogram (EEG) test, and then returned home. Within hours, he had a second seizure and went back to hospital.

His third seizure happened the next morning while walking to the nurse’s station.

In severe cases of listeriosis, bacteria can spread to the central nervous system and cause seizures, according to Health Canada.

“The last two months have really been a nightmare,” says Desmond, who has joined the proposed lawsuit.

When he returned home from the hospital, his daughter took a carton of Silk dark chocolate almond milk out of the fridge and asked if he had heard about the recall. By that point, Desmond says he was on his second two-litre carton after finishing the first in June.

“It was pretty scary. Terrifying. I honestly thought I was going to die.”

Cheryl McCombe, 63, Haliburton, Ont.

The morning after suffering a second episode of vomiting, feverish sweats and diarrhea in the middle of the night in early July, Cheryl McCombe scrolled through the news on her phone and came across the recall.

A few years earlier, McCombe says she started drinking plant-based milks because it seemed like a healthier choice to splash in her morning coffee. On June 30, she bought two cartons of Silk cashew almond milk.

“It was on the (recall) list. I thought, ‘Oh my God, I got listeria,’” McCombe says. She called her doctor’s office and visited an urgent care clinic hoping to get tested and confirm her suspicion, but she says, “I was basically shut down at the door.”

Public Health Ontario does not recommend listeria testing for infected individuals with mild symptoms unless they are at risk of developing severe illness, such as people who are immunocompromised, elderly, pregnant or newborn.

“No wonder they couldn’t connect the dots,” she adds, referencing that it took close to a year for public health officials to find the source of the outbreak.

“I am a woman in my 60s and sometimes these signs are of, you know, when you’re vomiting and things like that, it can be a sign in women of a bigger issue,” McCombe says. She was seeking confirmation that wasn’t the case.

Disappointed, with her stomach still feeling off, she says she decided to boost her gut health with probiotics. After a couple weeks she started to feel like herself.

But since then, McCombe says, “I’m back on Kawartha Dairy cream in my coffee.”

This report by The Canadian Press was first published Sept. 16, 2024.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

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