How 'Long Covid' continues to challenge patients five years on

Five years after the Covid-19 outbreak, the hidden impacts of the pandemic, 'Long Covid', still linger, often resurfacing or intensifying after common infections such as the flu.

'Long Covid', according to the World Health Organisation (WHO), is the persistence or recurrence of symptoms that last for weeks or months after a Covid-19 infection, even in cases where the initial illness was mild.

Common symptoms associated with 'Long Covid', according to the Organisation, include ongoing fatigue and low energy, shortness of breath, and cognitive difficulties such as memory problems, poor concentration, slower thinking, or general “brain fog”.

Patients may also experience chest discomfort or irregular heartbeat, lingering muscle or joint pain, sleep disturbances, and mental health effects such as anxiety, depression, or mood changes. Additional symptoms include headaches, dizziness, tingling, loss of taste or smell, and digestive issues such as nausea or diarrhoea.

The WHO emphasises that some less common but serious signs, including severe chest pain, difficulty breathing, fainting, or sudden neurological changes, require urgent medical attention. It notes that anyone who has had Covid-19 can develop 'Long Covid', regardless of the severity of the initial infection.

Studies indicate that heart, lung, and blood vessel damage can occur, increasing the risk of cardiovascular or pulmonary complications. Blood clotting issues and immune system abnormalities may reduce oxygen delivery to tissues, contributing to fatigue, cognitive difficulties, and shortness of breath.

A 2025 study conducted by researchers at the Icahn School of Medicine at Mount Sinai, New York, used advanced PET/MRI imaging to examine people with 'Long Covid' approximately one year after infection. Among 91 participants experiencing ongoing cardiopulmonary symptoms, over half showed signs of inflammation in the heart or lungs.

The study detected structural changes, including scarring or thickening of the heart muscle, fluid or inflammation around the heart, inflammation near heart valves, and inflammation in large blood vessels such as the aorta or pulmonary arteries.

Importantly, changes were often invisible on standard medical tests, indicating that hidden tissue damage and inflammation could persist even in people who appear clinically recovered. Blood analyses also revealed abnormal levels of immune-regulating proteins, supporting evidence of ongoing inflammation.

The findings suggest that 'Long Covid' may not be purely symptom-based but can involve real structural and functional damage to the heart and lungs, potentially increasing the risk of long-term cardiovascular or pulmonary complications.

Another 2025 study led by researchers at Stellenbosch University in South Africa identified persistent microscopic changes in the blood of people with 'Long Covid'. The study found numerous tiny microclots bound together with Neutrophil Extracellular Traps (NETs), a type of immune web.

The microclots and NETs were larger and denser in participants with 'Long Covid' compared to healthy individuals. Because they can block small blood vessels, these structures may reduce oxygen delivery to tissues, potentially explaining persistent fatigue, breathlessness, and cognitive difficulties commonly reported by patients.

A complementary South African study led by the University of Cape Town followed 97 individuals who had tested positive for Covid-19 during the first three pandemic waves, including those with mild, severe, and asymptomatic cases.

Follow-up assessments conducted between six months and two years after infection revealed a high burden of long-lasting neuropsychiatric and cognitive symptoms. More than half of the participants reported at least one ongoing issue, such as fatigue, memory loss, or “brain fog”.

Cognitive testing showed measurable impairment in 44 per cent of participants, 53 per cent reported memory problems, 55 per cent experienced moderate-to-severe fatigue, and about 25 per cent had significant anxiety or psychological distress.

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The severity of the initial infection did not reliably predict who would experience these long-term effects, and blood biomarkers failed to identify individuals at risk, indicating that standard medical tests cannot easily forecast these outcomes. The researchers emphasised the need for integrated care, including mental health support, cognitive rehabilitation, physiotherapy, and occupational therapy.

To reduce the risk of Long Covid and its impact, the WHO recommends vaccination. Protective measures such as wearing masks in crowded or poorly ventilated areas and practising good hand hygiene are also advised. Notably, maintaining a healthy lifestyle, including a balanced diet, regular exercise, and adequate sleep, supports the immune system and overall recovery.

WHO also highlights the importance of seeking early medical care and monitoring any lingering symptoms to prevent complications, particularly those affecting the heart, lungs, or neurological system. Managing chronic conditions such as diabetes, high blood pressure, or obesity can further reduce the risk of severe Covid-19 and long-term effects.

Globally, the WHO estimates that Covid-19 caused about 14.9 million deaths between January 2020 and December 2021, far higher than official counts, due to underreporting and misclassification.

In Kenya, official deaths were approximately 5,688, though analyses of excess deaths suggest the true toll may be much higher.

On vaccination, by the end of 2023, about 67 per cent of the global population had completed a full Covid-19 vaccine course, rising to 70.6 per cent with at least one dose by mid-2024. Around 13 billion doses have been administered worldwide; however, coverage remains uneven, with low-income countries lagging.