How a changing virus is …

By Julie Steenhuysen and Kate Kelland

CHICAGO, March 3 (Reuters) – Chris Murray, a University of Washington disease expert whose projections for COVID-19 infections and deaths are being followed closely around the world, changes his assumptions about the course of the pandemic.

Murray had until recently hoped that the discovery of several effective vaccines could help countries achieve herd immunity or nearly eliminate transmission through a combination of inoculation and previous infection. But over the past month, data from a vaccine trial in South Africa has shown not only that a rapidly spreading coronavirus variant may lessen the effect of the vaccine, but also evade natural immunity in people. people who had already been infected.

“I couldn’t sleep” after seeing the data, Murray, director of the Seattle-based Institute for Health Measurement and Evaluation, told Reuters. “When will this end?” he wondered, referring to the pandemic. He is currently updating his model to account for the ability of the variants to evade natural immunity and plans to provide new projections as early as this week.

A new consensus is emerging among scientists, according to Reuters interviews with 18 specialists who are closely monitoring the pandemic or working to limit its impact. Many have described how the breakthrough late last year of two vaccines with around 95% effectiveness against COVID-19 initially raised hopes that the virus could be largely contained, in the same way as the measles.

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

As a result, scientists said, people could be expected to continue to take measures such as wearing routine masks and avoiding crowded places during COVID-19 outbreaks, especially for those at high risk. .

Even after the vaccination, “I would still like to wear a mask if there was a variant,” said Dr. Anthony Fauci, chief medical adviser to US President Joe Biden, in an interview. “All you need is one flick of one variant (that triggers) another wave, and here’s your prediction” of when life will get back to normal.

Some scientists, including Murray, agree that the outlook could improve. The new vaccines, which have been developed at record speed, still appear to prevent hospitalizations and deaths, even when new variants are causing the infection. Many vaccine developers are working on booster injections and new inoculations that could preserve a high level of efficacy against the variants. And scientists say there is still a lot to learn about the immune system’s ability to fight the virus.

Already, COVID-19 infection rates have declined in many countries since the start of 2021, with dramatic reductions in serious illness and hospitalizations among the first groups of people to be vaccinated.

WORSE THAN THE FLU

Murray said if the South African variant, or similar mutants, continued to spread rapidly, the number of COVID-19 cases leading to hospitalization or death this winter could be four times that of the flu. The rough estimate assumes a 65% effective vaccine delivered to half the population of a country. In a worst-case scenario, that could add up to 200,000 deaths in the United States linked to COVID-19 during the winter period, based on the federal government’s estimates of annual deaths from the flu.

His institute’s current forecast, which ends June 1, assumes there will be 62,000 more deaths in the United States and 690,000 deaths worldwide from COVID-19 at this point. The model includes assumptions on vaccination rates as well as the transmissibility of the South African and Brazilian variants.

The change in the mindset of scientists has influenced more cautious government statements about the end of the pandemic. Britain said last week it expected a slow emergence of one of the tightest lockdowns in the world, despite one of the fastest vaccination drives.

The US government’s predictions of a return to a more normal lifestyle have been pushed back several times, most recently from late summer to Christmas, and then until March 2022. Israel issues immunity documents “Green Pass” to people who have recovered from COVID-19 or who have been. vaccinated, allowing them to return to hotels or theaters. The documents are only valid for six months as it is not known how long the immunity will last.

“What does it mean to have passed the emergency phase of this pandemic?” Said Stefan Baral, epidemiologist at the Johns Hopkins School of Public Health. While some experts have questioned whether countries could eradicate any case of COVID-19 completely through vaccines and strict lockdowns, Baral sees the targets as more modest, but still significant. “In my mind, the hospitals are not full, the intensive care units are not full and people are not passing tragically,” he said.

“SCIENTIFIC WHIPLASH”

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

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

Still, they had a lot to learn, including whether it would be possible to develop a vaccine against the virus and how quickly it would mutate. Could it be more like measles, which can be kept almost entirely at bay in communities with high inoculation rates, or the flu, which infects millions of people worldwide each year?

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

A major breakthrough took place in November. Pfizer Inc and its German partner BioNTech SE as well as Moderna Inc have said their vaccines are about 95% effective at preventing COVID-19 in clinical trials, a rate of effectiveness far higher than any influenza vaccine.

At least a few of the scientists interviewed by Reuters said that even after the results, they did not expect the vaccines to clear the virus. But many told Reuters the data gave hope in the scientific community that COVID-19 could be virtually eliminated, if only the world could be vaccinated quickly enough.

“We all felt pretty optimistic heading into Christmas with these first vaccines,” said Azra Ghani, president of infectious disease epidemiology at Imperial College London. “We didn’t necessarily expect high efficacy vaccines to be possible in this first generation.”

The optimism proved to be short-lived. At the end of December, the UK warned of a new, more transmissible variant that was quickly becoming the dominant form of the coronavirus in the country. Around the same time, researchers learned about the impact of the faster-spreading variants in South Africa and Brazil.

Phil Dormitzer, a senior vaccine specialist at Pfizer, told Reuters in November that the success of the US drugmaker’s vaccine indicated the virus was “vulnerable to vaccination” in what he called “a breakthrough for Humanity”. In early January, he acknowledged the variants heralded “a new chapter” in which companies will have to constantly monitor for mutations that could mitigate the effect of vaccines.

At the end of January, the impact on vaccines became even clearer. Data from Novavax’s clinical trials showed that its vaccine was 89% effective in a trial in the UK, but only 50% in preventing COVID-19 in South Africa. This was followed a week later by data showing that the AstraZeneca PLC vaccine offered only limited protection against mild disease against the South African variant.

The most recent change of mind has been significant, several scientists told Reuters. Shane Crotty, a virologist at the La Jolla Institute of Immunology in San Diego, called it a “scientific boost”: in December, he believed it was plausible to achieve so-called “functional eradication.” Of the coronavirus, similar to measles.

Now, “getting as many people vaccinated as possible is still the same answer and the same way forward as Dec 1 or Jan 1,” Crotty said, “but the expected outcome is not the same.”

(Reporting by Julie Steenhuysen in Chicago and Kate Kelland in London; additional reporting by Michael Erman in New York; Editing by Michele Gershberg and Cassell Bryan-Low)

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