New swine flu strain: Discovering new viruses not 'uncommon', but have to 'keep eye out' - Ashley Bloomfield

New Zealand's Director-General of Health says discovering new viruses isn't "uncommon", but we do have to keep an eye out for them and "be ready to respond if needs be".

Earlier this week, researchers in China revealed they had found a new strain of swine flu - referred to as G4 EA H1N1 - which had "all the essential hallmarks of a candidate pandemic virus". 

The study, which surveyed pigs between 2011 and 2018, published in the scientific journal Proceedings of the National Academy of Sciences also said people working with the pigs had been infected. 

While that showed the ability for the virus to pass from animals to humans, no evidence of human-to-human transmission has yet been found.

"Controlling the prevailing G4 EA H1N1 viruses in pigs and close monitoring in human populations, especially the workers in swine industry, should be urgently implemented," it said.

Kiwi Director-General of Health Dr Ashley Bloomfield told The AM Show he had read reports about the virus, but said new viruses aren't uncommon. 

"They have found this strain of a flu virus that is a new one that they haven't seen before. They have found that some of the people working with the pigs have been infected by it over a period of years, remembering the study only went through to 2018," he said.

"It is not uncommon for them to find these new viruses, and I think as the WHO said, [it is] a very timely, salutary reminder that these viruses are out there, they do change, and new ones do emerge. We have got to keep our eye out for them and be ready to respond if needs be."

Dr Bloomfield said the fact human-to-human transmission had not yet been detected was critical. 

"The other comment that was made is that there's no flu vaccine against it at the moment, but that's not surprising, because they do, of course, change the strains in the flu vaccine each year, but they would use the same technology, I would imagine, to be able to develop a vaccine if a new strain did emerge.

"That's one thing, there is existing, good knowledge and understanding of how to develop vaccines for influenza strains."

A World Health Organization (WHO) spokesperson is quoted by the BBC as saying that the organisation would closely look at the study. 

"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."

Dr Jemma Geoghegan, a virologist at the University of Otago, said any news that the next "viral pandemic" will be caused by a new virus found in pigs "might be a little premature".

"The main finding of this paper is that a new type of H1N1 flu called G4 has emerged in pigs, which probably happened around 2016. 

 "This G4 virus has only been found in pigs so far. They found that 10 percent of farmers already have the antibodies for this G4 strain. But there is no evidence that G4 is circulating in humans, despite the virus seemingly being around since 2016. 

"There is no evidence that G4 poses an immediate threat to humans but it is important to continue close monitoring and surveillance."

The H1N1 influenza virus is what led to the 2009 Swine Flu pandemic. There were about 18,450 lab-confirmed deaths reported to the WHO relating to that pandemic, but the death toll is estimated to be much higher by the United States' Centers for Disease Control and Prevention (CDC).

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