The study claims there is a neurological arm of long Covid, a respiratory branch and the third form is a diverse range of more severe and wide-ranging symptoms.
Those with neurological symptoms including fatigue, brain fog and headache – most commonly found among those who became infected when the most dominant strains were Alpha and Delta, the waves that struck in Christmas 2020 and then in spring 2021.
A second group experienced respiratory symptoms, including chest pain, lung issues and shortness of breath. This was found more commonly among those infected during the first wave of the virus in spring 2020 when people were unvaccinated.
Personalised diagnosis
The final group's symptoms include heart palpitations, muscle ache and pain, changes in skin and hair, as well as "debilitating multiorgan symptoms", King's College said.
But researchers said these three subtypes were evident in all variants but were unable to put a percentage risk on each one.
Clinical lead author Dr Claire Steves, from King's College London, said: "These data show clearly that post-Covid syndrome is not just one condition, but appears to have several subtypes.
"Understanding the root causes of these subtypes may help in finding treatment strategies.
"Moreover, these data emphasise the need for long Covid services to incorporate a personalised approach sensitive to the issues of each individual."
First author Dr Liane Canas, from King's College London, added: "This is the first study looking at subgroups of patients with specific post-Covid profiles and the effect of vaccination, prior to infection, to symptom profile.
"Given the time-series component, our study is relevant for post-Covid prognostication, indicating how long certain symptoms can last. These insights could aid in the development of personalised diagnosis and treatment for these individuals."
Research published last week from the University of Birmingham showed that the list of long Covid symptoms now stands at 62.
Loss of smell, shortness of breath and chest pain were the most common symptoms in the study, along with amnesia, an inability to perform familiar movements and hallucinations.
The researchers also calculated that those with Covid were 6.5 times more at risk of anosmia (loss of smell) 12 weeks after catching the virus than those who were not infected.
The risk was four times greater for hair loss, 2.6 times for ejaculation difficulty, 2.4 times for low libido and 1.8-fold for a hoarse voice.
This study also found the trend of people falling into one of three distinct categories of long Covid, and identifying where a patient sits may be able to help their treatment.
"This research validates what patients have been telling clinicians and policymakers throughout the pandemic – that the symptoms of long Covid are extremely broad and cannot be fully accounted for by other factors such as lifestyle risk factors or chronic health conditions," Dr Shamil Haroon, an associate clinical professor in public health at the University of Birmingham and lead author of the 62 symptoms study, said.
"The symptoms we identified should help clinicians and clinical guideline developers to improve the assessment of patients with long-term effects and to consider how this symptom burden can be best managed."
