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How deadly could China's covid outbreak become? Answers to this and more.

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China’s zero covid policy initially saved lives, kept hospitals from being overwhelmed, and gave the country time to roll out vaccines. But that has essentially pushed much of the impact of the pandemic into the future.

Now that future has arrived.

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When China ended the drastic lockdowns and restrictions that had been in place for three years, it sparked a surge of cases and deaths in a population with little natural immunity and low vaccine booster levels. With data on the scale of this covid outbreak being sparse and unreliable, scientists watching the Chinese crisis need to piece together scraps of evidence to predict the trajectory of this outbreak and what it might mean for the spread and evolution of the virus.

What will be the death toll in China? How long will the push last? And what will happen to the virus when it spreads through a country of 1.4 billion people? Definitive answers are extremely difficult to come by, in part because the Chinese government has not been transparent about the extent of the crisis. There are also scientific unknowns, including the effectiveness of Chinese vaccines.

But public health officials across the planet have plenty of data at this point about covid outbreaks in other countries, including countries that have opened up after enforcing a zero covid policy. This way, experts can make educated guesses about what’s in store for China in the weeks and months to come – while being ready to modify forecasts as more reliable information arrives.

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What will be the death toll in China?

Outside experts observing the outbreak predict hundreds of thousands of deaths in the coming months. Several modelers predict over one million covid deaths in China in 2023. The caveat: modeling is an inexact science, and there are many variables in the equation that could cause the death toll to rise or fall.

Airfinity, a UK-based company that analyzes life sciences data for its clients, has predicted 1.7 million deaths by April.

“That’s 1.7 million in the space of 4 months,” said Louise Blair, who leads the company’s epidemiology team, pointing to the “very strong growth” in cases. The company’s modeling draws heavily on the example of Hong Kong, which saw a rapid explosion of illnesses and deaths in early 2022 when the omicron variant arrived. Hong Kong, which had low vaccination rates, had maintained a zero covid policy that mirrored that of the mainland but was unable to contain the spread of omicron.

The University of Washington’s Institute for Health Metrics and Evaluation (IHME) has modeled the outbreak and projects 300,000 deaths by April 1 and 1.25 million by the end of the year – or until ‘to 1.6 million if there are no more mandates and restrictions, said institute epidemiologist Ali Mokdad.

Jeffrey Shaman, an epidemiologist at Columbia University who has studied the pandemic from the start, said in an interview that he expects something like 600 million to 900 million infections in China in 2023.

The death toll depends on the infection fatality rate of the virus, which is the ratio of deaths to infections. The rate is difficult to calculate. Infections often go undetected or are misdiagnosed, and deaths can be misattributed. The rate also changes over time depending on immunity levels, which can rise with vaccinations or fall due to the natural decline of antibodies.

According to Shaman’s estimate, the current infection fatality rate in the United States is about 0.15%. If this is true for China and its estimate of infections turns out to be accurate, it would lead to a death toll of between 900,000 and 1.35 million.

But Shaman points out that there are variables that could increase or decrease the death rate from infection. There is a lingering concern, for example, that Chinese vaccines may not be as effective in preventing serious illness as vaccines used in other countries.

“We’ve had so little information from China about what’s really going on,” he said. “Do we really have any idea what is going on there?

World Health Organization officials received a briefing from Chinese health authorities on December 21. 30 on the evolution of the country’s strategy to manage the covid. During the meeting, the WHO urged China to share information on the outbreak, including genetic sequence data and vaccination rates, especially among vulnerable people and people over 60.

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When will this wave of covid peak?

The slope of the epidemic curve is likely to be steep, just as it was in the United States last winter when the highly transmissible variant of omicron sickened tens of millions of people in just a few weeks and seriously affected the working population.

Airfinity predicts two peaks in the national infection count, one in mid-January and one in early March. This reflects the spread of the virus from major cities – where it would drive the previous peak – to more rural provinces. Each location in China would only have one peak. After that, China would experience what other countries have seen: “continuous waves” of infections, Blair said.

In an email, IHME’s Mokdad said he didn’t believe the Chinese government would allow hospital overflow and reimpose some of the mandates and restrictions that had been eased recently.

Additionally, people will develop their own response and are already limiting their movement, he said: “We have seen throughout the pandemic that people slow down when cases increase to protect themselves and their loved ones.”

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Will the explosion of coronavirus infections in China lead to a new variant?

This virus continues to mutate and has repeatedly surprised experts, so any prediction of what it will do next is risky. But there is no reason to think that the covid outbreak in China creates a special condition for the emergence of a new variant.

It’s certainly possible that a new variant will emerge in China, but another could also emerge anywhere on the planet as the virus continues to spread.

“There is significant circulation of this virus around the world, and the risk of new variants can come from anywhere,” WHO epidemiologist Maria Van Kerkhove said in an email.

There are more than 500 “sublines” of omicron already circulating around the world, she said.

The origin of new variants is never entirely clear, but they can emerge in several ways. One theory about the origin of the omicron is that it came from an immunocompromised patient who was unable to clear the virus for a very long time. In this scenario, the virus continued to mutate to evade the antibodies produced by therapeutic drugs and the natural human immune response. When omicron appeared, it already had dozens of mutations grouped together. It could happen again anywhere on the planet.

“There’s always a risk of new variants when there are a lot of infections, but that’s the least of my concerns about the situation in China,” said Kristian Andersen, an immunologist at Scripps Research who has been following the development. of the virus. E-mail.

“I’m much more concerned about the thousands of lives (probably tens to hundreds of thousands) that will be lost because of this. We should be focused on helping China and the Chinese people, including the emergency shipments of mRNA vaccines.” .”

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Is it wise to impose travel restrictions on China?

Tedros Adhanom Ghebreyesus, director-general of the WHO, neither endorsed nor condemned the travel restrictions, but he used the issue to confuse China into not sharing information with the rest of the world.

In the absence of complete information from [China]it is understandable that countries around the world are acting in a way that they believe can protect their populations,” he wrote on Twitter on December 29.

Other experts find the restrictions unnecessary and irrational.

“It makes no sense to me,” Shaman said in an email. “The travel restrictions seem designed to stop the virus at the border, which makes no sense given the virus is already everywhere.”

Andersen echoes this, calling the fear of new China-generated variants “completely misguided.”

“What would make sense would be to create a program to sequence aircraft wastewater to keep an eye out for variants from overseas (including China),” he said in an email. . This could then be combined with our own domestic (and clinical) wastewater monitoring for a more complete picture of circulating variants.

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