UK's National Health Service (NHS) is expecting a surge of COVID-19 cases this winter season combined with another health crisis that experts have been bracing for since summer. They are looking forward to flu cases increasing this year after almost vanishing in 2020 due to health protocols in place to prevent the spread of COVID-19.
This fear started when the Academy of Medical Sciences warned in July that up to 60,000 people might die due to the influenza virus from an average of between 10,000 to 25,000 a year. Also, experts said that the increase will be due to fewer people developing immunity against flu.
Vanishing Flu: How Does COVID-19 Pandemic Affect the Influenza Virus During Winter Season
The Curious Case of Vanishing Flu
According to Mail Online, the curious case of vanishing flu in 2020 is largely due to the social distancing imposed during lockdowns. This year, the NHS launched the biggest flu vaccination program in the history of the UK this September, in which 35 million people in England were given flu shots in preparation for the flu surge this winter.
The UK Health Security Agency (formerly known as Public Health England) showed in a recent report that flu cases last week were four times lower than the same week in 2019, with only three cases per 100,000 people. It is also half of the rate of the same week in 2018 that recorded 7.8 cases per 100,000 people.
Moreover, Google searches about flu have also decreased nearly 20 times than searches in the winter of 2019. Top geriatric doctors said there is little sign of influenza virus in hospitals, with only a few cases cropping up.
The same thing is also happening elsewhere in the world, like in Australia and New Zealand, which have their flu season during the summer months of the UK. Even Japan only recorded four cases, and China has 14,000 cases out of the 500,000 tested.
The World Health Organization (WHO) said that the recent global flu data remains well below levels compared to observed numbers in previous seasons. Experts predict that a flu epidemic is unlikely to happen in the UK this year despite earlier bleak predictions.
What Will Happen When the Flu Epidemic Comes Back?
The Scientist reported that the crucial question experts are now asking is what will the influenza virus look like when it returns. So many variants of flu may have disappeared during the pandemic, but did they vanish?
Currently, four types of influenza viruses are responsible for seasonal flu and other illness. Types A and B fall into the category of being the virus responsible for seasonal flu.
Type A is divided into subtypes of its surface proteins, hemagglutinin (H) and neuraminidase (N), that case H1N1 surge. Meanwhile, type B is divided into the B/Victoria and B/ Yamagata viruses, which can be further divided into clades and subclades based on their genes.
Infectious diseases epidemiologist Ben cowling from Hong Kong University said that the B/Yamagata lineage has disappeared in 18 months, and very few flu viruses have survived the COVID-19 pandemic. Scientists are unsure why some subgroups survive while others are gone. However, Hesley told The Scientist that perhaps some viruses can evade human immunity more effectively and are now more transmissible.
But scientists also wonder whether these viruses are not gone but only just biding their time to spread. Experts noted that those viruses that appeared to have vanished could still be in circulation at low levels somewhere and could rapidly increase transmission later. Thus, the vanishing flu viruses might be temporary, waiting for a severe flu season to evolve and develop diversity again.
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