Sunday , April 18 2021

“When will it end?”: How the changing virus is transforming scientists’ views on Covid-19



NEWS


Chris Murray, an expert at the University of Washington, whose predictions of Covid-19 infections and deaths around the world are being closely monitored, is changing his assumptions about the course of the pandemic.

Until recently, Murray hoped that the discovery of more effective vaccines would help states achieve herd immunity or nearly eliminate transmission through a combination of vaccination and prior infection.

But over the past month, data from a vaccine trial in South Africa have shown not only that a rapidly spreading version of the coronavirus can mitigate the effect of the vaccine, but it can also avoid natural immunity in people who have been previously infected.

“I couldn’t sleep” after seeing the data, said Murray, director of the Seattle-based Institute for Health Measurements and Assessment.

“When will it end?” he wondered when referring to the pandemic. It is currently updating its model to take into account the ability of the variants to evade natural immunity, and expects to make new predictions as early as this week.

According to interviews with 18 experts who are closely monitoring the pandemic or seeking to suppress its impact, a new consensus is emerging among scientists.

Many have described how the breakthrough of two vaccines with about 95% effectiveness against Covid-19 at the end of last year initially raised hopes that the virus could be largely retained, much like measles.

READ: Spicy journalist Karima Brown succumbs to Covid-19

But they say data on new versions from South Africa and Brazil has undermined that optimism in recent weeks. They now believe that SARS-CoV-2 will not only stay with us as an endemic virus that will continue to circulate in communities, but is likely to cause a heavy burden of disease and death in the years to come.

According to the scientists, people could expect to continue to implement measures such as routinely wearing masks and avoiding overcrowded places during Covid-19 overload, especially for high-risk people.

Even after vaccination, I would “still want to wear a mask if there was a version,” Dr. said in an interview. Anthony Fauci, chief health adviser to US President Joe Biden.

All you need is just a small stroke of the variant (which triggers) another wave, and your prediction goes

Anthony Fauci

“All you need is just a small shift of the variant (which triggers) another wave and comes to your predictions” about when life normalizes.

Some scientists, including Murray, acknowledge that the outlook could improve.

New vaccines that have been developed at a record rate still seem to prevent hospitalizations and death, even if new versions are the cause of the infection.

Many vaccine developers are working on restorative shots and new vaccinations that could maintain a high level of effectiveness compared to the variants. Scientists say there is still much to be learned about the immune system’s ability to fight the virus.

The number of Covid-19 infections has already declined in many countries since early 2021, and some serious illnesses and hospitalizations have fallen sharply among the first people vaccinated.

WORSE THAN THE FLU

Murray said if the South African version or similar mutants continued to spread rapidly, the number of Covid-19 cases hospitalized or died next winter could be four times the flu. A rough estimate predicts a 65% effective vaccine given to half of the country’s population.

In the worst case, this could mean up to 200,000 U.S. Covid-19 deaths, based on federal government estimates of annual winter flu deaths.

His institute’s current forecast, which runs through June 1, predicts that by then, an additional 62,000 U.S. and 690,000 deaths worldwide will have died from Covid-19. The model includes assumptions about vaccination rates and the portability of the South African and Brazilian versions.

The shift in thinking among scientists has influenced more cautious government statements about when the pandemic will end.

The UK announced last week that it expects a slow release from one of the strictest prisons in the world, even though it has one of the fastest vaccination campaigns.

READ: People infected with 501Y.V2 may have some immunity to the new version

U.S. government forecasts of a return to a more normal lifestyle have been pushed back several times, most recently from late summer to Christmas and then into March 2022.

Israel issues “Green Pass” immunity documents to people who have survived Covid-19 or have been vaccinated, allowing them to be returned to hotels or theaters. The documents are only valid for six months because it is not clear how long the immunity will last.

“What does it mean to pass the extraordinary phase of this pandemic?” Asked Stefan Baral, an epidemiologist at Johns Hopkins School of Public Health.

While some experts have questioned whether states could completely eradicate any Covid-19 case with vaccines and strict closures, Baral sees the goals as more modest but still meaningful.

“In my opinion, it’s that hospitals aren’t full, intensive care units aren’t full, and people don’t go through tragically,” he said.

“SCIENTIFIC BIG”

From the beginning, the new coronavirus has been a moving target.

At the start of the pandemic, leading scientists warned that the virus could become endemic and “may never go away,” including Dr. Michael Ryan, head of the World Health Organization’s emergency program.

Nevertheless, much remained to be learned, including whether a vaccine against the virus could be developed and how quickly it would mutate. Would it be more like measles, which can be almost entirely maintained in high-vaccination communities, or the flu, which infects millions of people worldwide each year?

For most of 2020, many scientists were surprised and convinced that the coronavirus had not changed enough to become more transmissible or deadly.

We did not necessarily expect such effective vaccines to be possible in this first generation

Azra Ghani

The big breakthrough happened in November. Pfizer and its German partner BioNTech as well as Moderna said their vaccines effectively prevented Covid-19 in clinical trials with an efficiency rate of about 95%, which is much higher than for all flu infections.

At least some of the scientists interviewed, Reuters said, did not expect vaccines to destroy the virus even after those results. But many have said the data in the scientific community raises hopes that Covid-19 could be virtually eliminated if only the world could be vaccinated fast enough.

“We all felt pretty optimistic with the first vaccines before Christmas,” said Azra Ghani, chair of infectious disease epidemiology at Imperial College London.

“We didn’t necessarily expect such effective vaccines to be possible in this first generation.”

Optimism proved short-lived. In late December, the UK drew attention to a new, more portable version that was rapidly becoming the dominant form of coronavirus in the country.

Around the same time, researchers learned of the impact of faster-spreading versions in South Africa and Brazil.

Phil Dormitzer, a top vaccine scientist at Pfizer, said in November that the success of the U.S. drugmaker showed the virus was “vulnerable to immunization,” which he called a “breakthrough for humanity.”

READ: How Covid-19 drives constant technological innovation

In early January, he acknowledged that the versions had announced a “new chapter” in which companies would have to constantly monitor for mutations that could reduce the effect of vaccines.

At the end of January, the impact on vaccines became even clearer. Data from clinical trials with Novavax showed that its vaccine was 89% effective in a trial in the United Kingdom, but only 50% effective in preventing Covid-19 in South Africa. A week later, data followed showing that AstraZeneca offered only limited protection against a mild disease against the South African version.

The latest heart change was significant, several scientists said.

Shane Crotty, a virologist at the La Jolla Institute of Immunology in San Diego, called it a “scientific scourge”: in December, he thought it was likely to achieve the so-called “functional eradication” of coronavirus, similar to measles.

Now, “vaccinating as many people as possible is still the same response and the same way forward as it was on December 1 or January 1,” Crotty said, “but the expected outcome is not the same.” – Reuters


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