Each winter sees some level of influenza circulating.
Ireland has experienced bad influenza seasons before, and the weeks ahead are shaping up to offer a testing season of festive flu and colds.
The flu this winter has come a few weeks early and is mainly being driven by a mutated A(H3N2) virus. Seasons that start early, tend to be more severe.
In recent years, the influenza strain A(H1N1) has been the more dominant strain, compared to the A(H3N2) which was dominant previously.
Because people have not encountered this strain much in recent years, there is less immunity against it.
The H3N2 strain of flu is virulent one, similar to the variant that caused the Hong Kong flu epidemic of 1968.
Professor Ronan Collins, Consultant Geriatrician at Tallaght University Hospital, said the flu is not just about a respiratory illness.
It can have very important effects on the heart and is a very important risk factor for stroke.
Professor Collins said that in some people it will cause a delirium, or a confusion in the brain, a kind of a toxic state in the brain, and in many cases, will hasten the onset of dementia.
Up to 75% of people can have influenza but with no symptoms, however they can transmit the infection.
According to the Health Protection Surveillance Centre (HPSC) there were 2,944 confirmed cases of influenza in the week to last Saturday and 657 patients were admitted to hospital with it.
The Government has said that well over three quarters of people in hospital now with influenza are not vaccinated.
Dr Conor Deasy, President of the Irish Association of Emergency Medicine, said this current strain is particularly nasty and the surge is hitting hospitals already under pressure with overcrowding.
Symptoms
Influenza-like illness is characterised by the sudden onset of symptoms with a temperature of 38°C or more, in the absence of any other disease, with at least two of the following: dry cough, headache, sore muscles and a sore throat.
The flu season last year was significant, with 21,297 cases reported. That compares with 11,751 cases in 2023 and 10,392 cases in 2022.
During the Covid-19 pandemic year of 2021, with lockdowns and restrictions and preventative measures, just 39 flu cases were reported.
In 2020, the year when the pandemic began, there were 7,775 cases of flu reported.
Flu deaths
This season so far, there have been 13 deaths due to influenza.
Influenza was made a notifiable disease here in January 2004.
During general flu seasons, there can be 200-500 deaths from influenza reported.
But in very bad seasons the figures can be much higher.
HPSC research suggest that there can be between 400-800 excess (additional) deaths may be due to influenza.
In a particularly severe season, between 1,000 and 1,200 excess (additional) deaths may be seen.
The HSE says that the illness can be more severe in the elderly, in those with chronic heart or lung disease, in children under four years of age, in people with cerebral palsy and pregnant women.
Eighty to 90% of reported deaths from influenza occur in the elderly, mainly from secondary bacterial pneumonia, but also from exacerbations of underlying disease, for example - chronic obstructive pulmonary disease, or cardiac disease.
The surge in flu cases is also adding to pressures on emergency departments, and we can see overcrowding levels rise.
While there are also cases of the Respiratory Syncytial Virus (RSV) and Covid-19 circulating, these are at much lower levels compared to the flu.
For example, there were 368 RSV confirmed cases and 176 confirmed cases of Covid-19 in the week to last Saturday.
There have been 7,506 confirmed cases of flu since this winter season began.
Most cases have been seen in Dublin, Cork, Westmeath, Galway and Wexford.
The fewest cases have been seen in Laois, Mayo and Monaghan.
According to the HPSC, in the Northern Hemisphere, the influenza season starts in October and continues through to May.
Ireland is not alone in facing the current surge. Health authorities in England are reporting the highest number of cases ever for this time of year and the NHS says it is facing a worst-case scenario. Cases are also rising in Northern Ireland.
In general, influenza outbreaks last between six to eight weeks and can affect all ages, in particular the extremes of age.
In the week to last Saturday there were 28 outbreaks in hospitals and 23 in nursing homes.
Nursing Homes Ireland has said that there is no alarm due to the level of preparation and given that social connection is a huge part of nursing home life, there will not be restrictions unless these are absolutely necessary.
Over 80% of nursing home residents have taken up the vaccine, which will help.
Low vaccine uptake by health staff
Doctors emphasise the best way for people to prepare for any flu season is to get vaccinated, ideally before the season starts.
But there is time and value in getting vaccinated now with Christmas Day around 11 days away and New Year's Day further ahead. The vaccine starts to work after about two weeks.
The HSE provides the flu vaccine free for many age groups, through GPs, pharmacies and in nursing homes.
The HSE target for uptake of flu vaccination for health staff is 75% but this has never been met and could be viewed as sending mixed signals to the public on a major public health issue.
The overall uptake by health staff has varied in recent years from as low as 18% (2011-2012) to over 71% (2020-2021).
For the 2024/25 season health staff uptake was 45%.
Health professionals are on the front line, so it is important for them to be protected and also to protect the patients they treat.
Stephen McMahon of the Irish Patients Association said that international evidence clearly shows that vaccinating healthcare workers, significantly reduces patient mortality and hospital-acquired influenza.
He said that health staff have rights and responsibilities, a point echoed this week by the Medical Council, which polices doctors in terms of their ethics and conduct.
Dr Suzanne Crowe, President of the Medical Council, said health staff being vaccinated will reduce the numbers of staff who will require sick leave and help ensure hospitals are adequately staffed for what is fast becoming a very busy period.
Enhanced vaccines
This week I revealed how the HSE did not offer the enhanced flu vaccine for over 65s, as it was not deemed cost-effective. Instead, a standard vaccine has been offered.
The Health Information & Quality Authority (HIQA) estimated that switching to an adjuvant vaccine for people 65 years and older, rather than the standard flu vaccine, may be the best use of resources, but it depended on cost.
Here the HSE is pitted against the drug makers and the cost being sought by some of the firms was deemed too much. Ten countries offer the enhanced flu vaccine free of charge to some or all the over 65s age group.
The question will be posed to what degree would the current and likely pressures in the weeks ahead on hospitals, GPs and for patients have been eased, had the HSE been able to provide the enhanced vaccine this season?
Dr Colm Henry, the HSE Chief Clinical Officer, said that the vaccine on offer is "highly effective" and that all licenced influenza vaccines for this season comply with World Health Organisation recommendations.
A report in the British Medical Journal this week noted fears that the vaccines now in circulation may not be as effective as hoped against the current strain.
As a result, some people may think the jabs ineffectual and may have not bothered to get the latest flu vaccine at all. But doctors say this is the wrong approach because the vaccine works as expected.
Indeed, recent data from the UK shows that the current flu vaccines are 70-75% effective at preventing hospital admission in 2–17-year-olds and 30-40% effective at preventing hospital admission in adults.
Planned operations postponed
Traditionally around the Christmas and the New Year season, hospitals wind down planned surgeries and procedures. It allows staff to take time due and enjoy the festive season. Also, people do not want to be in hospital around this time of year if that can be avoided.
But with influenza likely to peak during Christmas week and plateau off slowly after, there may be more planned operations postponed this year than usual. Hospitals will also have to deal with flu outbreaks and may have to curtail visiting, something which caused much anxiety for patients and families during the Covid-19 pandemic.
All the indications are that we are heading into a very tough season for patients, health staff and the wider health system.
