Understanding the origin of SARS-CoV-2

More than a year after the COVID-19 pandemic began, it is still unclear how it began. Dr. Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center, has become one of the key scientific voices calling for a more thorough investigation of the origin of SARS-CoV-2. Knowing how this pandemic began will help science think about how to best mitigate the risk of a future pandemic.

Prior to SARS-CoV-2, Bloom and his team in Fred Hatchin’s Department of Basic Sciences focused on the evolution of the influenza virus. However, as SARS-CoV-2 became a global threat last year, they switched gears and asked applied questions about antibodies and vaccines used to treat and prevent viral infections, how it evolved. I studied what that evolution means for me.

As the pandemic was increasingly suppressed in the United States, Bloom and other scientists began to focus on understanding how the pandemic began. This spring, Bloom spoke publicly to support a more in-depth investigation in collaboration with other experts in his field.so Letter published in scienceBloom and 17 other scientists argued that “it is necessary to clarify the origin of this pandemic and it is feasible to achieve it.” Until we have enough data, we must take the hypothesis about both natural and laboratory spillovers seriously. “

In the question and answer session, we asked Bloom to explain the importance of understanding the origin of the pandemic in the context of understanding the virus and preventing future outbreaks.

Why is it important to understand how the COVID-19 pandemic began?

bloom: Understanding the origin of SARS-CoV-2 will help you learn how to maximize the power of science to reduce the risk of future viral outbreaks.

Currently, there is no clear evidence of how the SARS-CoV-2 virus emerged. The deep ancestor of SARS-CoV-2 is the bat-derived coronavirus, but so far no direct ancestral bat virus has been identified that is closely related to SARS-CoV-2. There are two main theories as to how the bat ancestral virus led to the outbreak of a pandemic in Wuhan. One theory is that there was a natural zoonotic disease in which the virus jumped directly from bats to humans or was transmitted from bats to intermediate animal hosts and to humans. Another theory is that one of the Wuhan Institutes had an accident dealing with the bat coronavirus.
Both theories are plausible given the evidence currently available. As a scientist, I also believe that it is important to clearly communicate that there is scientific uncertainty. In particular, this is a hot button topic. The work of scientists like me should take a more objective and calm approach so that the discussion is organized in terms of scientific facts rather than the many strong opinions some people have on this topic. Is to do. And unfortunately, the facts are limited at this point.

What do you think happened? Was it an accidental laboratory leak or spontaneous?

bloom: Most pandemics start that way, so zoonotic diseases are plausible. For example, four of the last five influenza pandemics started with zoonotic diseases, but one (the 1977 influenza pandemic) was due to human error. In the case of coronaviruses, we know that in the past there were other animal coronaviruses that caused outbreaks in humans by direct jumps from animals to humans. These include the original SARS-CoV-1 and MERS-CoV. When I heard about SARS-CoV-2 in January 2020, my first assumption was that it was likely to have jumped from a bat.

However, there was also an accident in the laboratory. For example In 2004, many people in Beijing were infected with SARS-CoV-1 in a laboratory accident... The reason the laboratory accident is a plausible explanation for the origin of SARS-CoV-2 is that one of the major laboratories studying coronaviruses like SARS is in Wuhan, where many researchers are. It is known to have collected the coronavirus. There is no evidence that they have collected a virus that is sufficiently similar to SARS-CoV-2 and became its direct ancestor.

Therefore, I joined an open letter published in Science magazine with other scientists and asked for further research. We are not claiming that one scenario is more likely than another. We just point out that the existing scientific evidence is not enough to know what happened. If you want a clear answer, you need to investigate further on this topic.

Why was it important for science to issue an open letter?

bloom: I am one of 18 scientists. Signed the letter Published in Journal Science on May 13th..

I wanted a letter published in a scientific magazine. Our goal of practicing scientists, writing letters, and publishing them in scientific journals is that how the pandemic began is ultimately a scientific issue, not a political one. Was to remind people.

Some of us have begun drafting letters to support calls from the World Health Organization and the US government to further investigate the origin of the virus. We have contacted other scientists with relevant expertise who are currently studying SARS-CoV-2 and viral evolution. Most other scientists who contacted agreed to sign the letter.

How was the reaction to the letter?

bloom: I still have a lot of emails. Many from other scientists who support the need for more research say that further research is distracting. Most people agree that the science is unclear, but the assessment of the relative potential of laboratory accidents and zoonotic diseases varies from person to person. As a scientist, I’m used to the idea of ​​dealing with uncertainty, but I’m not used to dealing with uncertain topics with so many people. I want Even if the evidence remains unclear, one may be true.

However, it is encouraged by the growing consensus on the need for further investigation. Of course, scientists and experts make different speculations about the relative potential of laboratory accidents and zoonotic diseases, as many basic facts about early SARS-CoV-2 cases remain unclear. doing. However, there is a common view that more careful scientific research is needed.

What do you want from another survey? And how likely is it that you have to think so much in China?

bloom: It is clear that further research is needed to determine the origin of the virus.

Ideally, we could gain more access to the underlying data on coronavirus sequences studied in the Wuhan laboratory and more insight into the early human cases of COVID-19. I will.

There are complex and political aspects that are beyond my control. My job as a scientist is to focus on knowing the truth.

Some have rejected Labreak’s idea as a conspiracy theory, while others have wondered if it was intentional. What is your view?

bloom: We don’t have enough scientific evidence to rule out anything. In my view, the study should include studies of both zoonotic and laboratory accidents.

I don’t think intentional liberation is a plausible theory. There is no motive, and all the signs show that the outbreak was a surprise to China, as in other parts of the world, which does not apply in the case of intentional liberation.