A significant number of people experience long-term health problems after recovering from the initial infection.
Covid-19 can cause persistent health problems with long-term effects.
There is no precise data on Brazil, but the British National Statistics Institute (ONS) estimates, for example, that around 1.3 million people in the United Kingdom have the so-called “long covid”, symptoms that last more than four weeks.
Most people who get covid don’t get seriously ill and get better relatively quickly.
But some have long-term problems after recovering from the original infection, even if they didn’t get very sick initially.
What are the symptoms of long covid?
Long-term covid is not fully understood, and there is no internationally agreed definition, so the measurement of how common it is or what symptoms are involved will vary.
Guidance for UK healthcare professionals describes long-term covid as symptoms that continue for more than 12 weeks after an infection, and which cannot be explained by another cause.
According to the NHS website, the UK’s public health system, these symptoms can include:
- Extreme tiredness;
- Shortness of breath, heart palpitations, chest pain or tightness;
- Problems with memory and concentration (“mental fog”);
- Changes in smell and taste;
- Joint pain.
But patient surveys have identified dozens and even hundreds of other symptoms. A large study by University College London (UCL) identified 200 symptoms that affect 10 organ systems.
These include hallucinations, insomnia, changes in hearing and vision, short-term memory loss, and speech and language difficulties. Other patients have reported gastrointestinal and bladder problems, changes in their menstrual cycle and skin conditions.
The severity of symptoms varies, but many have been unable to perform tasks such as bathing or remembering words. However, these symptoms can also have other causes.
The ONS survey, published in September 2021, found that 0.5% of people who tested negative for coronavirus had at least one symptom that lasted three months, compared with 3% of those who tested positive.
How do I know if I have long covid?
There is currently no standard test, doctors first rule out other possible causes for the symptoms.
Thus, patients with suspected the disease will likely undergo other tests, to check for diabetes, thyroid function and iron deficiency, for example, before receiving a diagnosis of long covid.
It is possible that a blood test will be available in the future.
What causes long covid?
We still don’t know for sure.
It could be that the initial infection causes some people’s immune systems to become overwhelmed, attacking not just the virus but their own tissues.
The virus itself entering and damaging our cells can explain some symptoms like loss of smell and taste, while damage to blood vessels can, for example, contribute to heart and lung problems.
Another theory suggests that fragments of the virus may remain in the body, possibly dormant, and then be reactivated.
This happens with some other viruses, such as the herpes virus and the Epstein Barr virus, which causes mononucleosis.
However, there is currently not much evidence that this happens in the case of covid.
There are likely to be a lot of different things happening to different people to cause such a wide variety of problems.
Who is most vulnerable and how common is it?
This is difficult to define because doctors have only recently started recording long covid.
The latest ONS estimate suggests that around 1.3 million people in the UK have the disease. Of these, 892,000 (70%) first contracted the virus at least 12 weeks ago, and 506,000 (40%) at least one year ago.
The survey asked nearly 352,000 people to record their own symptoms. And that suggests the condition is more common among:
- People from 35 to 69 years old;
- People with underlying conditions that limit their daily activities;
- Professionals working in the area of health and social assistance;
- People living in poorer areas.
In April, the ONS indicated that about one in 10 people with covid had symptoms lasting at least three months.
But in September it suggested that ratio was one in 40.
The statistics will continue to change as more data is collected, and will vary depending on the definitions used.
And the kids?
Are children less likely than adults to get covid and therefore less likely to develop long-term covid? but some still develop.
However, in August 2021, leading industry experts said they had been reassured about the incidence of long-term Covid in young people after the world’s largest study on the topic showed persistent symptoms were less common than feared.
Some early estimates had suggested that up to half of all children who caught coronavirus would develop long-term covid.
A team of researchers, led by the Great Ormond Street Institute of Child Health, investigated more than 200,000 positive cases of covid among young people aged 11 to 17 from September 2020 to March 2021.
They believe that around 4,000 to 32,000 of them still had symptoms 15 weeks later.
We don’t know the severity of the symptoms, but there was little evidence that the children had been bedridden or unable to go to school.
The researchers noted, however, that the risk to young people “is not trivial”, and said it is vital that children receive the necessary medical care.
Can the vaccine help?
Some reports suggest that people who have been vaccinated are less likely to have long-term covid.
Vaccination can help prevent people from contracting the virus in the first place and thus developing long covid.
It may also prevent infections from “turning” into long-term covid, but this is less clear.
What treatments are available?
There are currently no proven drug treatments, and the main focus is on controlling symptoms and gradually increasing activity.
Studies on the best way to identify, treat and improve the lives of people with long-term covid are ongoing.