Market in China's Wuhan likely origin of COVID-19 outbreak: Study

The origin of the SARS-CoV-2 virus that causes COVID-19 remains a mystery and a major source of tension between China and the United States.

Reuters

November 19, 2021 / 12:11 IST

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The first known COVID-19 case was a market vendor in the Chinese city of Wuhan, not an accountant who appeared to have no link to the market but whose case contributed to speculation the virus could have leaked from a lab, according to a US study.

The origin of the SARS-CoV-2 virus that causes COVID-19 remains a mystery and a major source of tension between China and the United States.

A joint study by China and the World Health Organization (WHO) this year all but ruled out the theory that COVID-19 originated in a laboratory, saying that the most likely hypothesis was that it infected humans naturally, probably via the wildlife trade.

A WHO-led team of experts spent four weeks in and around the central city of Wuhan with Chinese scientists and said in a joint report in March that the SARS-CoV-2 virus had probably been transmitted from bats to humans through another animal but that further research was needed.

The accountant, who was widely thought to be the first person with COVID-19, reported that his first symptoms appeared on Dec. 16, several days later than initially known, Michael Worobey, head of ecology and evolutionary biology at the University of Arizona, said in the study published in the journal Science on Thursday.

COVID-19 Vaccine

Frequently Asked Questions

How does a vaccine work?

A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.

How many types of vaccines are there?

There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.

What does it take to develop a vaccine of this kind?

Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.

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