It is shaping up to be the country’s worst flu crisis in 50 years

The super-charged Australian flu virus sweeping Ireland has affected people across the country in an alarming numbers and has created a crisis for the health service on a new scale.

It is now shaping up to be the country's worst flu crisis in 50 years, with 20,000 patients swamping doctors' surgeries and hundreds being admitted to hospital.

Figures from the Health Protection Surveillance Centre show the number of flu cases reported in Ireland during the first week of this year was 81pc higher than the same period last year.

Hospitals are already operating at capacity, but medical experts suggest this hyper-virulent flu strain has barely got started. According to the latest figures released last Wednesday, one in two people reported to be suffering from an infectious disease is struggling with influenza.

With its roster of tell-tale symptoms - sudden fever, aching body, sore throat, exhaustion, difficulty sleeping, loss of appetite - Australian flu sounds familiar enough. However, it is the strain's ferocity, coupled with its unusually long recovery time (flu symptoms tend to subside after a week or so, but the so-called H3N2 strain can last much longer), the low-level effectiveness (20-30pc) of the current vaccine and the vastly increased potential for fatalities that have marked it out.

When H3N2 hit Australia last year, during their winter, it led to the country's worst flu season for nearly a decade. The 72 reported deaths went well beyond the high-risk vulnerable group of young babies, the chronically sick and elderly. They included a mother-of-two in her 30s, a young father, an eight-year-old girl and an 18-year-old law student. Some 217,000 people were infected - many times more than the previous record of 100,000 in 2015.

The new strain has spread throughout Ireland exactly 100 years after Spanish flu, the world's worst pandemic, killed upwards of 50 million people worldwide.

The threat of a repeat crisis on a similar scale is not far from the minds of international experts today.

"We will get another similar virus again and we will potentially have another pandemic," says Professor Wendy Barclay, an expert in virology at Imperial College London. "We hope not - but we can't exclude the possibility."

Flu virus mutates at random, producing a shape-shifting pathogen that can suddenly acquire deadly virulence. Intensively farmed pigs and poultry are particularly susceptible to flu outbreaks, as per the 2009 swine flu outbreak, with crowded living conditions providing a perfect environment for the development of mutations that can cross species into humans, potentially causing a new and deadly global pandemic to match the 1918 disaster.

"There is always the potential for viruses to emerge from animal sources," says Prof Barclay. "It is not something you can accurately predict."

"The basic problem is the instability of the flu virus," says Professor Robert Dingwall of Nottingham Trent University, a former member of the UK's flu pandemic planning committee. "All we can do is take the best guess on what strains have been around for the past two years.

"Australian flu is not new, but vulnerable people don't seem to be responding as well to the vaccine as we might have hoped, and so it's more serious." He believes the false sense of security following many winters of relatively low-level flu infection could also have disastrous consequences "with more deaths and more hospitalisations".

What you need to know to avoid illness

Here is what you need to know about Australian flu — and how to better protect yourself against it.

What exactly is flu?

It is a group of viruses that attach to the lining of the lungs. The symptoms of high fever, nausea, vomiting and diarrhoea are side-effects of inflammation caused as the immune system goes into overdrive to fight it off. The virus is divided into A, B, C and D categories, depending on its capacity for mutation and infection. Types A and B are the most dangerous to humans. The letters H and N in the strain refer to up to 18 types of haemagglutinin protein and 11 types of neuraminidase protein on the surface of the virus. These proteins affect the ability of the virus to attach itself to the lining of the lungs.

How is this Australian flu strain different?

The H3N2 type A strain — nicknamed Australian flu because of where its outbreak was first reported — is similar to the H3N2 Hong Kong flu that caused a pandemic in 1968, killing a million people. The Health Protection Surveillance Centre (HPSC) says iInfluenza B and A (H3N2) are currently the predominant viruses here with more influenza B than is usually observed at this time of year.

Why has Australian flu struck now?

Flu viruses travel around the world causing most infections in winter. Prof Robert Dingwall of Nottingham Trent University says it is not clear if Australian flu is causing more of a problem because it’s more virulent, or whether we have lost resistance to it. Prof Wendy Barclay of Imperial College London says flu infections are worse in winter, but the reasons are not clear. It may be because the virus survives best in cold damp air. Australian flu also leaves the body susceptible to other strains, as well as other infections.

Is it too late to be vaccinated?

No: the current risk from Australian flu could continue for months. HPSC says you will develop antibodies within 10 to 14 days of receiving the jab.

Flu vaccinations — designed to protect against Australian flu as well as some other strains — are available to everyone aged over 65, and those with a long-term medical condition (such as chronic lung disease, heart disease, neurological disorders, neurodevelopmental disorders and diabetes). You should also speak to a GP if you have a weakened immune system — for example, due to chemotherapy.

Parents are also being urged to seek vaccination for their young children. Pregnant women, nursing home residents, healthcare workers and anyone with morbid obesity should also get immunised.

Are healthcare staff vaccinated?

Vaccination is currently voluntary, and the HSE has confirmed most healthcare workers had not received the vaccine.

What else can be done to avoid it?

Crowded indoor spaces — such as school classrooms and warm offices — are a particular risk. If you travel on public transport, use hand sanitising gel until you can wash your hands properly in warm, soapy water. If you must sneeze or cough in public, don’t cover your mouth with a tissue, as virus particles can be transferred on to your hands. Instead, virologists say sneezing or coughing into the crease of your arm far reduces the likelihood of the contagion spreading.

Does the vaccine work?

The vaccine protects against the three strains of flu virus recommended by the World Health Organisation. If you have been vaccinated and you come into contact with the virus, antibodies will attack it and stop you from getting sick. It is tailored to specific strains of flu and is based on predictions. Historically, this has not proved terribly effective or accurate, with large numbers of vaccinated people often still developing flu.

Lois Rogers

Sunday Independent