Doctors in the UK have released details of what they believe to be the longest Covid-19 infection on record, lasting more than 16 months.
The patient, who had underlying conditions, had detectable levels of the virus for 505 days, and died in hospital last year.
Most people recover quickly on their own, but in rare cases, infections can become prolonged in those with weakened immune systems.
Experts suspect extended infections in those who are immunocompromised play a role in creating Covid-19 variants, because the virus has more time to experiment and learn how to avoid defences.
The patient in the UK first caught the virus in early 2020.
Dozens of positive tests
The infection was confirmed by a PCR test, which was repeated each time the person visited hospital over the next 72 weeks, about 50 times in total.
The patient tested positive every time, never becoming clear of the virus, despite receiving antiviral treatment.
Tests revealed it was the same infection and no mutations were spawned.
“We have seen few patients with positivity of Covid [for] even more than three months, but we haven't come across [any] like those reported — more than 16 months,” said Dr Sarla Kumari from Canadian Specialist Hospital Dubai.
“Anyone with multiple comorbidities and a weak immune system can find it difficult to eradicate the virus.”
Cases of such prolonged infections are rare, but viral persistence is suspected in playing a role in long Covid, a much more common problem characterised by lingering symptoms.
In that theory, which is one of several to explain the phenomenon, the virus hides out in the body somewhere, continuing to wreak havoc.
“Long Covid is the term used when people experience Covid-19 symptoms for more than 12 weeks,” said Dr Karthikeyan Dakshinamurthy, a specialist in internal medicine at NMC Royal Hospital DIP.
“The most common symptoms patients experience are fatigue, chest tightness or shortness of breath, inability to concentrate on work and dizziness.”
Symptoms can include long-term changes in smell or taste.
“Long Covid symptoms can happen in normal people without any risk factors. They need to rule out other causes of these symptoms. People should understand long Covid symptoms,” Dr Dakshinamurthy said.
This week it was revealed that a woman caught two Covid variants in 20 days — the shortest gap so far confirmed by genome sequencing.
The 31-year-old healthcare worker first tested positive using a PCR test on December 20, 2021, 12 days after receiving a booster shot. She was totally asymptomatic.
But on January 10, 21 days after her previous positive test, she began to feel unwell with a cough and fever. She performed another PCR test, which was also positive.
The infections were caused by the Delta and Omicron variants.