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Long Covid case study: progress report 2

This is the second in my series of blogs giving progress reports on the Long Covid case study programme. To receive email updates, please add your details here.

This progress report gives an overview of the study design and the symptoms experienced by the case study participants . To read about the background to this case study and learn more about Long Covid, please see my previous blog.

How were participants recruited to this programme?

I let people know about the opportunity to participate in the case study programme through my Instagram and Facebook profiles, and selected six applicants, representing a range of experiences and symptoms of Long Covid. All had positive swab tests, antibody tests or GP diagnosis of the original Covid infection or Long Covid.

Prospective participants were provided comprehensive written information on what the case study programme involved, and were able to discuss this information and any questions, during an online or phone appointment, before giving their formal written consent to the use of their anonymised microbiome data and case history details in this research.

While I am donating my time and consultation fees to this programme, participants needed to be able to self-fund the cost of prebiotic supplements, probiotics and a reduced-price stool test, and this unfortunately excluded several applicants, including those who had lost work due to Long Covid. I paid careful attention to the importance of selecting participants with a diversity of ages, ethnicities and bodyweights, as this can affect people's experiences of Covid. However, this proved ultimately impossible, due to applicants wanting to continue other therapies that directly affect the gut microbiome, withdrawing their application, or having additional longterm health conditions that would have made measuring the impact of microbiome interventions very difficult within the 12 week study period.

Which participants were selected?

Five participants are female, and one is male, aged 38–55. All participants are white (British, European and non-European) with a BMI ranging from 20–32. None of the participants had been admitted to hospital with Covid and the severity of their initial illness ranged from mild to moderate. People aged over 50 and female are currently thought to be among those most at risk of developing Long Covid symptoms [1] and the makeup of this small group reflects this.

Two participants had developed Long Covid after initially considering themselves to have recovered from their initial illness and returning to work (from home). While the impacts of their symptoms on their activity and quality of life vary, all are currently unable to return to their previous work commitments or levels of activity prior to Covid. Most are undergoing continued medical investigations for their symptoms, and all had been unwell for more than three months at the start of the programme.

What symptoms do they have?

Each participant has a unique collection of classic Long Covid symptoms with clusters of 16 to 59 different symptoms, including neurological, cognitive, cardiac and respiratory symptoms. All participants report ongoing fatigue, brain fog (including impaired memory and concentration) as well as painful symptoms.

All participants have varying degrees of symptom severity, with relapsing and remitting patterns, and two participants still need to spend days in bed during relapses. Most are unable to exercise, have trouble sleeping and report headaches, blurred vision and eye strain. Out of a total of more than 85 ongoing symptoms reported by this group, ongoing aches and pains (including joint pain, nerve pain, muscle pain), shortness of breath, dizziness, heart palpitations (or periods of irregular or fast heartbeats), dizziness, altered smell, hot flashes or chills, or alcohol intolerance are each experienced by 3/6 participants (see Figure 1).

Figure 1: Symptoms reported by two or more participants: All participants suffer brain fog and fatigue as primary symptoms, as well as one or more ongoing painful symptoms such as nerve pain, headaches and muscle pain. (The full list of symptoms is based on the Indiana University Survivor Corps survey[2] and case history sessions at the start of the programme.)

What's next?

Using comprehensive microbiome stool tests, I will be looking in detail at each individual’s gut bacterial profile, especially looking at species known to contribute to inflammation and those known to protect from inflammation. So far I have analysed five of the six microbiome stool samples taken at the start of the programme.

I have prescribed a range of prebiotics and probiotics as well as recommended increases or decreases in certain foods as appropriate. All recommendations are tailored to each participant’s unique gut bacterial profile, current symptoms and case history. All my recommendations are based on clinical trial data for the prebiotics and probiotics used in this study, together with the latest medical research and clinical knowledge of the role of the gut microbiome in inflammation and microbiome alterations with certain foods.

Outcomes will be measured through follow-up microbiome stool tests and symptom reporting (including the use of validated instruments for measuring outcomes that are used widely in clinical trials). We're hoping we will see the balance of the microbiome shifting over the coming weeks, and that they will soon be experiencing an improvement in symptoms.

I will publish more detailed microbiome analyses, treatment protocols and outcomes at a later date. To receive email updates on this case study and news from my practice, please add your details here.


With thanks to:

Each of the study participants for their enthusiasm and commitment to this programme.

Dr Fran Smith for consulting on study ethics and the informed consent process.

Dr Jason Hawrelak for his advice and input on study design and treatment protocols.

Biomesight for sponsoring this programme with free and reduced-price test kits.

Viola Sampson BSc is a microbiome analyst practising in London, UK and online. To book an appointment, please see

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