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Even as the COVID-19 pandemic continues to spread across the world, a new strain of swine flu has been found in China which has the potential to trigger the next pandemic.

Though the newly discovered virus has not been identified to be of immediate concern, researchers say it has "all the essential hallmarks of a candidate pandemic virus". And as is the case with new or previously unidentified viruses, humans may not have any immunity to fight it off.

This is exactly what happened with COVID-19: it is caused by a new coronavirus—the SARS-CoV-2—that no one had heard of until 2019.

Coronaviruses are so-called because of the crown-like spikes on their surface. Before COVID-19, coronaviruses have caused outbreaks like the SARS (severe acute respiratory syndrome) outbreak in 2002-03 and the MERS (Middle East Respiratory Syndrome) outbreak 2013.

In the six months since it was discovered in late 2019, though, COVID-19 infection has exceeded the death toll of SARS and MERS combined. More than 10 million people have fallen sick because of COVID-19 and over half a million have died globally.

To be sure, the new swine flu is caused by an influenza virus and not a coronavirus. Like coronaviruses, influenza viruses are RNA viruses (their genetic material is RNA) covered in a spherical membrane. They use host cells to survive and multiply.

Read more: World’s deadliest viral infections

According to a study published in the Proceedings of the National Academy of Sciences (PNAS), scientists have reported that the new swine flu virus, similar to previous swine flu outbreaks, has the potential to mutate further and lead to a worldwide outbreak. The 2009 swine flu pandemic was spread by the H1N1 virus that had originated from pigs and mutated to infect humans, but turned out to be less deadly than previously thought.

Earlier in 2020, a haemorrhagic fever caused by the African swine flu virus (ASF) was also reported in domestic pigs in the northeastern state of Assam, and even as the World Organisation for Animal Health classified it as a "notifiable disease" due to a high mortality rate among pigs, the dangers to humans were minimal as this particular strain of virus is not known to affect humans. However, much like other viruses, the ASF virus also has the potential to mutate.

  1. Why are scientists concerned about the new swine flu virus?

Scientists said the new swine flu virus is similar to the one discovered in 2009, called A/H1N1pdm09, and codenamed the new virus G4 EA H1N1.

This new virus is said to have the potential to attach to human cells and multiply in a person's respiratory system. They reported on an influenza virus surveillance of pigs between 2011 and 2018 in China, and found that as was the case in 2009, the new genus of the swine flu virus can bind to human cell receptors, and could also infect other animals such as ferrets.

This is similar to the behaviour of the SARS-CoV-2 virus, which has been reported to have first jumped from bats to pangolins before going on to infect humans. (Research is still on to figure out exactly how SARS-CoV-2 evolved to infect humans and which animals were involved in its mutation and transmission, but the most widely accepted hypothesis currently involves pangolins and bats.)

The scientists noted that upon further investigation, swine workers had already been exposed to the virus as 35 out of a total of 388 workers tested positive for the G4 EA H1N1 virus, and were aged between 18 and 35 years old, showing that the virus has already started infecting human beings. This indicates that the virus has already started to mutate and adapt to be able to invade human cells, increasing the possibility of snowballing into a pandemic in the future.


  1. Sun H et al. Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection. Proceedings of the National Academy of Sciences. 2020 Jun; 201921186.
  2. Centers for Disease Control and Prevention [internet], Atlanta (GA): US Department of Health and Human Services; Key Facts about Swine Influenza (Swine Flu) in Pigs.
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