Whilst research is ongoing, much is still unknown about how COVID-19 will affect people over time. Although most people with COVID-19 get better within weeks of illness, some people experience post-COVID symptoms for much longer. Clinical Immunologist, and Immunopathologist Dr Daman Langguth explains more about “Long COVID”, a term which has been adopted to describe people who have had symptoms continuing for more than 12 weeks after an infection - severe or mild - which can't be explained by another cause.

“We know that COVID-19 can damage the lungs, heart and brain, which increases the risk of long-term health problems. This usually occurs in patients who have had very severe disease, causing significant toxicity in their lungs, brain, or other organs. This is not what I think Long COVID is referring to at the moment. Long COVID, as I see it, is a varying symptom complex which occurs after a viral infection. That in itself is not uncommon – if you look at Epstein-Barr virus (EBV) in adults and in children, a significant number of people experience fatigue for a period of time after. In fact, if you look at any severe infection, lots of people feel unwell for a long time afterwards. It doesn’t really matter what that infection is – it could be any severe disease.

“Most people who have had COVID-19 normally recover completely within a few weeks, however in a small percentage of people, symptoms can persist for months. It remains unclear how many people are affected by Long COVID, however what we do know is that older people and people with many serious medical conditions are the most likely to be affected by lingering symptoms. From what we can tell, Long COVID involves a wide range of symptoms which affect many parts of the body. The most commonly reported are fatigue, shortness of breath, chest pains, cognitive changes, headaches, sensory changes and pain,” said Dr Langguth.

After suffering from other viral-type illnesses, it is not uncommon for people to report having persistent fatigue, brain fog and other symptoms that similar to those experienced with Long COVID. This similarity in symptoms suggests that Long COVID may a be general post-infectious process and not be unique to COVID-19.

“Using the term “Long COVID” could be confusing as it suggests that the COVID-19 virus is replicating in the body long term, but there is no evidence to suggest this is the case. In around 95% of people the COVID-19 virus is gone within weeks - what you are dealing with in those small percentage of cases are the after-effects of inflammation. Unlike most viruses of this nature, COVID-19 causes inflammation in the lining of the blood vessels. This inflammation is what makes us feel unwell and can have detrimental effects on the human body, especially when it does not resolve and becomes persistent, as in COVID-19.

“The problem we have is that many of the symptoms of Long COVID can stem from a variety of other conditions, therefore it is important to investigate patients presenting with symptoms. Just because someone has had COVID-19 doesn’t mean there is not another underlying cause. It may be possible that symptoms have been present before COVID-19 infection and the infection simply triggered a response,” said Dr Langguth.

It's important to remember that most people who have COVID-19 recover quickly. But the potentially long-lasting problems from COVID-19 make it even more important to reduce the spread of COVID-19 by following precautions. This includes wearing masks, social distancing, avoiding crowds, getting a vaccine when available and keeping hands clean.

“People forget that this is the first time in history that we have ever studied such a huge outbreak in terms of both vaccination and disease. We have been able to collect data in real time which we have not done during an outbreak of this scale before. I think if we had the data collection that we have now in the 1919 flu epidemic, you might have seen very similar effects,” said Dr Langguth.