First there was long Covid, then long colds. Now, we have long flu, according to a new study.
Since the Covid-19 pandemic, scientists have studied the way the virus can attack a patient’s organ systems, leaving them with long-term and often disabling health problems in a condition known as ‘long Covid’.
People have long drawn similarities between Covid-19 and influenza, particularly when it comes to some of the common symptoms like fever, headaches, and a cough.
But now, researchers have found another parallel – this time when it comes to the impacts of illnesses.
A new study by Washington University School of Medicine and the Veterans Affairs St Louis Healthcare System has found that people hospitalised with the flu can suffer long-term, negative health effects – especially relating to their lungs and airways.
The research also discovered that, in the 18 months after hospitalisation for the flu, patients faced an increased risk of death, organ health problems, and readmission to hospital – in a similar pattern to those who were hospitalised for Covid-19, although at much lower levels.
‘Five years ago, it would never have occurred to me to examine the possibility of a ‘long flu,’ said senior author Ziyad Al-Aly, a clinical epidemiologist at Washington University.
‘A major lesson we learned from Covid is that an infection that initially was thought to only cause brief illness can also lead to chronic disease.
‘This revelation motivated us to look at long-term outcomes of Covid-19 versus flu.
‘We wanted to know whether and to what degree people with flu also experience long-term health effects, and the answer is that the flu can lead to long-term health problems – just like Covid-19.’
Dr Al-Aly also noted that the risk to health was highest after the first month of infection – refuting the commonly-held notion that these kinds of diseases are short-term ones.
‘Many people think they’re over Covid-19 or the flu after being discharged from the hospital,’ she explained.
‘That may be true for some people. But our research shows that both viruses can cause long-haul illness.’
Common long Covid symptoms
- Extreme tiredness (fatigue)
- Feeling short of breath
- Loss of smell
- Muscle aches
- Problems with your memory and concentration (‘brain fog’)
- Chest pain or tightness
- Difficulty sleeping (insomnia)
- Heart palpitations
- Dizziness
- Pins and needles
- Joint pain
- Depression and anxiety
- Tinnitus, earaches
- Feeling sick, diarrhoea, stomach aches, loss of appetite
- A high temperature, cough, headaches, sore throat, changes to sense of smell or taste
- Rashes
Source: NHS
However, while both viruses can result in ‘long’ suffering, the study showed that the risk of death and loss of health was ‘substantially’ higher among Covid-19 patients than among flu patients.
The notable difference was in the fact that while flu primarily poses dangers to the respiratory system, Covid-19 is more ‘indiscriminate’ and can attack any organ system.
‘Covid-19 is more likely to cause fatal or severe conditions involving the heart, brain, kidneys, and other organs,’ said Dr Al-Aly.
To carry out this study, researchers analysed anonymised medical records in a database maintained by the US Department of Veterans Affairs – the nation’s largest integrated healthcare delivery system.
Looking at 81,280 patients hospitalised for Covid-19 between March 1, 2020 and June 30, 2022, and 10,985 patients hospitalised for influenza between October 1, 2015 and February 28, 2019, the study then evaluated the effects that came to the fore over the following eighteen months.
They found that infection and hospitalisation with either virus carried an increased risk of disability and disease, even if to varying levels.
Those hospitalised with Covid-19 had a 68% increased risk of health conditions across all organ systems, while those hospitalised with the flu had a 6% increased risk of health conditions – most of which were in the respiratory system.
The main difference between the two diseases related to the risk of death, with those who suffered from Covid-19 being 50% more likely to die than those who suffered from flu.
Covid-19 patients also experienced an increased risk of readmission to hospital, as well as an increased risk of admission to an intensive care unit – for every 100 persons, there were 20 more hospital admissions and nine more ICU admissions for Covid-19 than for flu.
Concluding the study, which has been published in The Lancet Infectious Diseases, Dr Al-Aly wrote: ‘Our findings highlight the continued need to reduce the risk of hospitalisation for these two viruses as a way to alleviate the overall burden of health loss in populations.
‘For both Covid-19 and seasonal influenza, vaccinations can help prevent severe disease and reduce the risk of hospitalisation and death.
‘This is especially important for vulnerable populations such as the elderly and people who are immunocompromised.’
She also further highlighted how the study dismisses the misconception that Covid-19 and flu are ‘acute’ or short-term illnesses.
‘Before the pandemic, we tended to belittle most viral infections by regarding them as somewhat inconsequential: “You’ll get sick and get over it in a few days”,’ she said.
‘But we’re discovering that is not everyone’s experience. Some people are ending up with serious long-term health issues which eclipse the problems they faced in the early phase of infection.
‘We need to wake up to this reality and stop trivialising viral infections and understand that they are major drivers of chronic diseases.’
MORE : Can’t shake the sniffles? You may have a ‘long cold’
MORE : Scientists identify troubling new long Covid symptom
MORE : Mum-of-four suffering ‘torture’ of long Covid wants to end life in Switzerland
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