Collective immunity will not save us from the coronavirus pandemic – National

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Throughout the months of March and April, Spain was one of the countries hardest hit by the coronavirus.

Since then, the epidemic has slowed, but the country has so far registered about 253,000 cases and 28,000 deaths – more than twice as many cases and three times more deaths than Canada, according to data from the University. Johns Hopkins.

But even with all of these cases, most of the 47 million Spaniards remain vulnerable to the disease.

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Study finds only 5% of the Spanish population has anti-coronavirus antibodies, despite a serious epidemic

A study released this week found that only about 5% of the Spanish population had antibodies showing that they had encountered the virus. In Madrid, which experienced one of the largest outbreaks, the number was only around 10%. Furthermore, it seemed that these antibodies had disappeared within a few months.

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Experts say this is bad news for proponents of natural “collective immunity” – the idea that if enough people catch the virus, the population will ultimately be protected from future epidemics.

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“We are a long way from reaching a level of immunity that would protect Spain from future epidemics,” said Ashleigh Tuite, infectious disease epidemiologist at the University of Toronto.

“I think it’s really a cautionary tale and a warning to other places that it’s going to be with us for a while. And even in the hardest hit places, they are still vulnerable to waves of subsequent infections. “

About “collective immunity”

Usually, according to Tuite, the term “collective immunity” is used to describe immunization coverage. As in, you need around 95 percent of people to be vaccinated against measles so that this group is protected from future measles epidemics.

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You can also get immunity from a disease without being vaccinated, but it takes a lot of people to get it.

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Dr. Nelson Lee, a professor at the University of Alberta who studies infectious diseases, says that for influenza, you start to get a little protection from the population at around 40% immunity, but for real protection, it must be closer to 70% of immunized people.








Coronavirus epidemic: collective immunity is not a concept that should be supported, “says Tam

Coronavirus epidemic: collective immunity is not a concept that should be supported, “says Tam

“In fact, we do not know what level of collective immunity is required for COVID-19,” he said, adding, “There would be a huge price to pay” to reach a level similar to that of influenza.

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“If you infect a lot of people in the community, there will be a lot of serious illness and death.”

Even in Sweden, where infection rates were higher because there were few restrictions at the start, there has been little demonstrated immunity, he said, despite a very high death toll.

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What is collective immunity and what does it mean for COVID-19?

It’s also unclear exactly how the presence of antibodies, which most tests are looking for, translates into immunity against a new infection, Tuite said.

“We don’t really know for sure,” she said. “Because it is a new virus, we can examine the immune response and examine the antibodies and try to deduce how many people have been infected.” But we don’t really know how long-lasting this immunity is. ”

“I think a huge assumption with any sort of strategy based on collective immunity is that immunity is long-term, which we don’t fully know at this point.”

End the pandemic

The bottom line, Tuite thinks, is that it would be a bad idea to let the virus run its course until enough people have been infected to theoretically achieve collective immunity.

“Collective immunity may be an outcome that occurs during the pandemic, but it should not be a strategy.”

The infection curve would not stop only when 70% of people were infected either, she said – cases would tend to decline slowly over time.

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And while the idea of ​​letting the virus run its course was launched in the UK at the start of the pandemic, and countries like Sweden have chosen not to close at the same level as their neighbors, Tuite said. it was not aware of any country actively pursuing collective immunity as a strategy at this time.










Coronavirus outbreak: evidence shows that collective immunity has not been reached


Coronavirus outbreak: evidence shows that collective immunity has not been reached

However, parts of the United States could test this by default, she said. “There is a strategy of letting the virus spread without really concentrating or making efforts to control it. The uncontrolled spread is sort of saying de facto, “Well, we will leave that spread until we have immunity in the population.”

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With an uncontrolled spread, we can expect a “substantial proportion [of people] would develop a serious illness, and some of them will have to be hospitalized and die, “said Lee. There are also reports of people who have lasting damage or long-term symptoms as a result of COVID-19.

For all these reasons, a commentary published alongside this week’s study on Spain called a collective immunity strategy both “highly unethical” and “unworkable”.

It would be far better to end the pandemic with a vaccine, Lee thinks.










When will a COVID-19 vaccine be ready?


When will a COVID-19 vaccine be ready?

Until that happens, Tuite said, we must emulate the countries that control their outbreaks. “These are tests, contact tracing, isolation of infected people,” she said, as well as personal interventions such as physical distance and the use of masks.

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“I think at this point it is enough to keep the number of manageable cases and allow us to live with this virus until we have the vaccine.”

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© 2020 Global News, a division of Corus Entertainment Inc.



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