‘When will it end?’: How a changing virus is reshaping scientists’ views on COVID-19


CHICAGO (Reuters) – Chris Murray, a disease expert at the University of Washington whose projections for COVID-19 infections and deaths are closely followed around the world, is changing 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 prior infection. But in the past month, data from a vaccine trial in South Africa showed not only that a fast-spreading variant of the coronavirus could attenuate the effect of the vaccine, it could also evade natural immunity in people who had previously been infected.

“I couldn’t sleep” after looking at the data, Murray, director of the Seattle-based Institute for Health Metrics and Evaluation, told Reuters. “When will it end?” he wondered, referring to the pandemic. It is currently updating its model to take into account the ability of variants to escape natural immunity and hopes to provide new projections starting this week.

A new consensus is emerging among scientists, according to Reuters interviews with 18 specialists who are closely following the pandemic or are working to stem its impact. Many described how the advancement late last year of two vaccines about 95% effective against COVID-19 had initially raised hope that the virus could be largely contained, similar to how the virus has been. 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, it will continue to circulate in communities, but will likely cause a significant burden of disease and death in the years to come.

As a result, the scientists said, people could expect to continue taking steps such as routinely wearing masks and avoiding crowded places during COVID-19 surges, especially for people at high risk.

Even after vaccination, “I’d still want to wear a mask if there was a variant out there,” Dr. Anthony Fauci, chief medical adviser to US President Joe Biden, said in an interview. “All you need is a small movement of a variant (that causes) another wave, and there goes your prediction” about when life returns to normal.

Some scientists, including Murray, acknowledge that the outlook could improve. New vaccines, which have been developed at record speed, still appear to prevent hospitalizations and death, even when the new variants are the cause of the infection. Many vaccine developers are working on booster shots and new shots 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.

COVID-19 infection rates have already declined in many countries since early 2021, with some drastic reductions in serious illness and hospitalizations among the first groups of people to get vaccinated.

WORSE THAN THE FLU

Murray said that if the South African variant, or similar mutants, continue to spread rapidly, the number of COVID-19 cases resulting in hospitalization or death this coming winter could be four times that of the flu. The rough estimate assumes a 65% effective vaccine administered to half the population of a country. At worst, that could account for as many as 200,000 COVID-19-related deaths in the US during the winter period, based on federal government estimates of annual flu deaths.

His institute’s current forecast, which runs through June 1, assumes there will be 62,000 additional deaths in the United States and 690,000 global deaths from COVID-19 by then. The model includes assumptions about vaccination rates, as well as the transmissibility of the South African and Brazilian variants.

The shift in thinking among scientists has influenced more cautious government statements about when the pandemic will end. Britain said last week that it expects a slow exit from one of the world’s toughest lockdowns, despite having one of the fastest vaccination campaigns.

The US government’s predictions of a return to a more normal lifestyle have been repeatedly delayed, most recently from late summer through Christmas and then through March 2022. Israel issues “Green Pass” immunity documents to people who have recovered from COVID-19 or have been vaccinated, allowing them to return 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 have passed the emergency phase of this pandemic?” Said Stefan Baral, an epidemiologist at the Johns Hopkins School of Public Health. While some experts have asked if countries could completely eradicate any COVID-19 cases through vaccines and strict lockdowns, Baral sees the goals as more modest, but still significant. “In my opinion, it is that the hospitals are not full, the ICUs are not full and people do not die tragically,” he said.

“SCIENTIFIC WHIPLASH”

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

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

However, 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. Would it be more like measles, which can be almost completely kept at bay in communities with high inoculation rates, or the flu, which infects millions of people around the world each year?

For much of 2020, many scientists were shocked and made sure that the coronavirus had not changed enough to become more transmissible or deadly.

November saw a breakthrough. Pfizer Inc and its German partner BioNTech SE, as well as Moderna Inc, said their vaccines were about 95% effective in preventing COVID-19 in clinical trials, an efficacy rate that is much higher than any flu vaccine.

At least some of the scientists interviewed by Reuters said that even after those results, they did not expect the vaccines to eliminate the virus. But many told Reuters the data raised hope within the scientific community that COVID-19 could be virtually eliminated, if only the world could get vaccinated quickly enough.

“We are all quite optimistic before Christmas with those first vaccines,” said Azra Ghani, chair of infectious disease epidemiology at Imperial College London. “We didn’t necessarily expect such highly effective vaccines to be possible in that first generation.”

The optimism was short-lived. In late December, the UK warned of a new, more transmissible variant that was fast 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, one of Pfizer’s top vaccine scientists, told Reuters in November that the success of the US drugmaker’s vaccine indicated the virus was “vulnerable to immunization” in what he called “a breakthrough for humanity. “. In early January, he acknowledged that the variants heralded “a new chapter” in which companies will have to constantly monitor mutations that could attenuate the effect of vaccines.

In late January, the impact on vaccines became even clearer. Novavax clinical trial data showed that its vaccine was 89% effective in a UK trial, but only 50% effective in preventing COVID-19 in South Africa. That 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 in opinion was considerable, several of the scientists told Reuters. Shane Crotty, a virologist at the La Jolla Institute for Immunology in San Diego, described it as a “scientific whiplash”: In December, he had believed it plausible to achieve the so-called “functional eradication” of the measles-like coronavirus.

Now, “vaccinating as many people as possible is still the same answer and the same way forward as on December 1 or January 1,” Crotty said, “but the expected result is not the same.”

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

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