New swine flu virus could cause future pandemic

Source: Liz West (via Flickr)
New strain of swine flu virus called G4-EA-H1N1 discovered in China with ability to infect humans.

By Alex Brown

The word pandemic, defined as “the worldwide spread of a new disease”,  has recently become part of everyday language through the COVID19 outbreak. With the death toll growing each day it is well on the way to becoming one of the most prevalent pandemics of the century. 

It may come as a shock to know that COVID19 is not the only pandemic out there. HIV is still described as an ongoing pandemic and researchers in China may have found the next one; a new strain of swine flu virus called G4-EA-H1N1. The virus is carried by pigs and has been seen to be able to infect humans.

Swine flu was last widely reported during the 2009 pandemic caused by the strain A/H1N1pdm09. The new virus shares similarities in its growth pattern and its site of development in the epithelial cells lining the airways. The new virus however has one deadly adaptation. The 2009 virus was less deadly than initially feared due to similarities with viruses that had circulated before, giving people some immunity to it. 

However, when the new strain was tested against human influenza vaccine strains, it was shown that pre-existing population immunity does not provide protection against G4 viruses. This means the population would be more susceptible and the virus could more rapidly spread from person to person. It is this lack of immunity that increases the viruses prevalence. 

Researchers have been monitoring the virus since 2011 and have identified it in 10.4% of swine workers tested. It appears that the 18-35-year-old cohort had the highest prevalence of the virus with 9 out of 44 workers testing positive. This shows that the predominant G4 EA H1N1 virus has acquired human infectivity, which greatly enhances the virus’ ability to further adapt and mutate in humans, raising concerns for possible future pandemic viruses. 

Although current flu vaccines do not protect against this new virus they can be adapted to; the flu vaccine is regularly altered to keep up with ever-mutating viruses. This is discussed in bi-annual meetings. This was confirmed in a statement by a World Health Organization spokeswoman: “Eurasian avian-like swine influenza viruses are known to be circulating in the swine population in Asia and to be able to infect humans sporadically. Twice a year during the influenza vaccine composition meetings, all information on the viruses is reviewed and the need for new candidate vaccine viruses is discussed. We will carefully read the paper to understand what is new.

“It also highlights that we cannot let down our guard on influenza; we need to be vigilant and continue surveillance even during the COVID-19 pandemic.”

Although the virus is not believed to be an immediate problem, this study acts as a reminder that a flu pandemic could theoretically happen at any time due to the constant emergence of new pathogens. Farmed animals, such as pigs, are an important intermediate host for the generation of pandemic influenza viruses, and thus, monitoring of these is a vital measure in forewarning of future virus outbreaks. 

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