Response to "Was the rate of Long Covid as high as 45%–a scary report with flaw"

We would like to thank Dr Yao and colleagues for their interest in our systematic review and for taking the time to express their concerns, which were listed in four key questions.

In relation to point one, the concern related to the calculation of a different and lower prevalence estimate than reported in our systematic review based on re-calculation of data presented in the supplementary material (Table S3). As stated in the methods section of our paper, symptom prevalence data from individual studies were pooled and meta-analysed using a random effects model. When calculating an average this method weights the pooled estimate by study size, and therefore different prevalence estimates will be attained by simply totalling numbers across studies to calculate a simple percentage (as per the data provided by Yao and colleagues). When calculating a pooled effect size, random effects meta-analysis assigns larger studies with more precise effect size estimates greater weight than smaller studies with less reliable estimates.¹ The formula for random effects models can be found in full in a 2010 paper by Borenstein et al.² When we report in our study "With an average study follow-up time of 126 days, the pooled prevalence of COVID-19 survivors experiencing at least one unresolved symptom, regardless of hospitalisation status, was 45%"? We have used random effects meta-analyses to calculate the pooled prevalence of experiencing at least one resolved symptom across all studies, and then we have calculated the mean follow-up time across all studies.

In addition to this, the data used as the basis of Yao and colleagues' re-analysis – ‘at least one or more symptom’ was not presented in Table S3. When creating this descriptive table, we provided symptom specific data in the table. Following their comment, we have amended Table S3 to remove this column to avoid any confusion. To provide further clarity we have presented the data extracted and used in our review (i.e. study values) for the three exemplar studies identified by Yao and colleagues (Table 1). Two of the three papers (O'Keefe et al. and Tessitore et al.) did not report ‘at least one symptom at follow up’ the data presented by Yao and colleagues in their Table 1 relates to individual symptoms by the corresponding studies and therefore would not have been extracted. We would like to thank the authors for highlighting that Venturelli et al., did report data for ‘At Least 1 Symptom at Follow-up’ (i.e., “51.4% still complained of symptoms). This symptom was not extracted in our original analysis. Adding this data point did not change the associated pooled estimates, but the CI changed marginally; 52.6 (95% CI: 43.5, 61.6) to 52.6 (95% CI: 43.6 to 61.5). We would like to take this opportunity to highlight that a 10% random sample of the extracted data was cross-checked by a second reviewer.

Table 1.

Data extraction for three exemplar studies.

Author	Total	With symptom	Males (%)	Age	Hospital status	Time to FU	FU time point	Continent	Symptom
O'Keefe (A)a	304	16	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Cough
O'Keefe (A)	304	7	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Headache/Migraine
O'Keefe (A)	304	10	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Exertional Breathlessness
O'Keefe (A)	304	4	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Sore Throat
O'Keefe (A)	304	7	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Chest Pain/Tightness
O'Keefe (A)	304	4	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Abdominal Pain
O'Keefe (A)	304	7	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Joint Pain
O'Keefe (A)	304	10	31.8	45.7	Non-hospitalised	≥30	Symptom Onset	North America	Nasal Symptoms
Tessitore	165	10	62	58	Hospitalised	365	Discharge	Europe	Muscles Weakness/Pain
Tessitore	165	1	62	58	Hospitalised	365	Discharge	Europe	Fever
Tessitore	165	4	62	58	Hospitalised	365	Discharge	Europe	Gastro-intestinal Problems
Tessitore	165	45	62	58	Hospitalised	365	Discharge	Europe	Fatigue
Tessitore	165	1	62	58	Hospitalised	365	Discharge	Europe	Sputum
Tessitore	165	8	62	58	Hospitalised	365	Discharge	Europe	Headache/Migraine
Tessitore	165	23	62	58	Hospitalised	365	Discharge	Europe	Breathlessness
Tessitore	165	1	62	58	Hospitalised	365	Discharge	Europe	Nasal Symptoms
Tessitore	165	5	62	58	Hospitalised	365	Discharge	Europe	Cough
Venturelli	767	395	67.1	63	Hospitalised	81	Discharge	Europe	At Least 1 Symptom at Follow-upb
Venturelli	767	39	67.1	63	Hospitalised	81	Discharge	Europe	Arrhythmia
Venturelli	767	23	67.1	63	Hospitalised	81	Discharge	Europe	Cough
Venturelli	767	24	67.1	63	Hospitalised	81	Discharge	Europe	Chest Pain/Tightness
Venturelli	767	16	67.1	63	Hospitalised	81	Discharge	Europe	Impaired Kidney Function
Venturelli	767	4	67.1	63	Hospitalised	81	Discharge	Europe	Headache/Migraine
Venturelli	767	33	67.1	63	Hospitalised	81	Discharge	Europe	Depression
Venturelli	767	222	67.1	63	Hospitalised	81	Discharge	Europe	PTSD
Venturelli	767	4	67.1	63	Hospitalised	81	Discharge	Europe	Fever
Venturelli	767	2	67.1	63	Hospitalised	81	Discharge	Europe	Cognitive Dysfunction
Venturelli	767	121	67.1	63	Hospitalised	81	Discharge	Europe	Impaired Usual Activity
Venturelli	767	228	67.1	63	Hospitalised	81	Discharge	Europe	Breathlessness
Venturelli	767	30	67.1	63	Hospitalised	81	Discharge	Europe	Palpitations
Venturelli	767	186	67.1	63	Hospitalised	81	Discharge	Europe	Fatigue
Venturelli	767	23	67.1	63	Hospitalised	81	Discharge	Europe	Confusion/Brain Fog
Venturelli	767	82	67.1	63	Hospitalised	81	Discharge	Europe	Anxiety

Note: Since all data related to the prevalence of people, when the calculated n value was not a whole number it was rounded up to the next highest whole number.

^aConverted from % to absolute values.

^bNot extracted in the original data extraction but added now. Converted from %.

We would also like to note that although Dr Yao and colleagues suggest our prevalence estimates differ from a credible recent publication, the publication that they reference is not a meta-analysis. When compared to other meta-analyses, our prevalence estimates are similar.^3,4 Specifically, the study by Chen and colleagues found a pooled prevalence of 49% at 120 days which very similar to our finding of 45% at a mean follow-up 126 days.³ Additionally, as the authors acknowledge in their paper, a key limitation of the study referred to is that coded symptom data in primary records is likely to underrepresent the true symptom burden experienced by individuals with persistent symptoms. Moreover, the authors explicitly state that “the symptom data we used for the study thus cannot be used to make inferences about the absolute prevalence of these symptoms”, as has been done by Yao and colleagues.

In point two, Yao and colleagues discussed the impact of follow-up duration on prevalence estimates. As stated above, a meta-analysis was used which weights study estimates depending on sample size. A simple percentage based on total numbers of patients across studies will result in a different estimate. In addition, the prevalence estimates presented in our paper relate to the average follow-up time of all studies. We did not limit the analysis to studies with follow-up longer than 111 days. As all studies covered a period of time, limiting the analysis to studies >4 months (or 111 days) would not provide a prevalence estimate for an average of 4 months. Rather it would provide an approximate prevalence estimate across studies with a follow-up of at least 4 months, resulting in an average follow-up that is necessarily longer than 4 months. It is reasonable to expect that symptom prevalence will reduce over time since acute infection, as some patients’ symptoms will resolve (either spontaneously or with intervention from healthcare services). Thus, by only including studies with follow-up longer than 4 months, it is not surprising that Yao and colleagues produced a prevalence estimate that is lower than our own. However, we do agree that the variability in prevalence estimates is high and previously acknowledged this within the manuscript on Page 5 “Between studies heterogeneity was high for the majority of meta-analyses, ranging from 2 to 99.9%.” We also provide confidence intervals for the pooled prevalence of any symptom across all groups 44.8% (95% CI 38.6%–51.2%).

In point three, Yao and colleagues discuss the accuracy of data extraction. We do appreciate it is difficult to identify the correct corresponding publication based on the names of the author alone. Therefore, we have now included full references in our corrigendum (and in Table 2 below) for all studies included in the analysis. With regards to the three papers that were crosschecked by the authors for accuracy,⁵ as discussed above, the data included in Table S3 was not specific to at least one symptom at follow up, rather it was a range of varying symptom codes. We appreciate that this may cause confusion and as mentioned previously, we have removed the column for clarity.

Table 2.

List of included study references.

Lead Author	Full Reference
Ahmed	Ahmed GK, Khedr EM, Hamad DA, Meshref TS, Hashem MM, Aly MM. Long term impact of Covid-19 infection on sleep and mental health: A cross-sectional study. Psychiatry Res. 2021;305:114243.
Akter	Akter F, Mannan A, Mehedi HMH, Rob MA, Ahmed S, Salauddin A, et al. Clinical characteristics and short term outcomes after recovery from COVID-19 in patients with and without diabetes in Bangladesh. Diabetes Metab Syndr. 2020;14(6):2031-8.
Armange	Armange L, Bénézit F, Picard L, Pronier C, Guillot S, Lentz PA, et al. Prevalence and characteristics of persistent symptoms after non-severe COVID-19: a prospective cohort study. Eur J Clin Microbiol Infect Dis. 2021;40(11):2421-5.
Arnold	Arnold DT, Hamilton FW, Milne A, Morley AJ, Viner J, Attwood M, et al. Patient outcomes after hospitalisation with COVID-19 and implications for follow-up: results from a prospective UK cohort. Thorax. 2021;76(4):399-401.
Asadi-Pooya	Asadi-Pooya AA, Akbari A, Emami A, Lotfi M, Rostamihosseinkhani M, Nemati H, et al. Risk Factors Associated with Long COVID Syndrome: A Retrospective Study. Iran J Med Sci. 2021;46(6):428-36.
Augustin	Augustin M, Schommers P, Stecher M, Dewald F, Gieselmann L, Gruell H, et al. Post-COVID syndrome in non-hospitalised patients with COVID-19: a longitudinal prospective cohort study. Lancet Reg Health Eur. 2021;6:100122.
Aul	Aul DR, Gates DJ, Draper DA, Dunleavy DA, Ruickbie DS, Meredith DH, et al. Complications after discharge with COVID-19 infection and risk factors associated with development of post-COVID pulmonary fibrosis. Respir Med. 2021;188:106602.
Aydin	Aydin S, Unver E, Karavas E, Yalcin S, Kantarci M. Computed tomography at every step: Long coronavirus disease. Respir Investig. 2021;59(5):622-7.
Ayoubkhani	Ayoubkhani D, Bermingham C, Pouwels KB, Glickman M, Nafilyan V, Zaccardi F, et al. Trajectory of long covid symptoms after covid-19 vaccination: community based cohort study. Bmj. 2022;377:e069676.
Babaei	Babaei A, Iravani K, Malekpour B, Golkhar B, Soltaniesmaeili A, Hosseinialhashemi M. Factors associated with anosmia recovery rate in COVID-19 patients. Laryngoscope Investig Otolaryngol. 2021;6(6):1248-55.
Baricich	Baricich A, Borg MB, Cuneo D, Cadario E, Azzolina D, Balbo PE, et al. Midterm functional sequelae and implications in rehabilitation after COVID-19: a cross-sectional study. Eur J Phys Rehabil Med. 2021;57(2):199-207.
Barry	Barry HC. More than One-Half of Adults Hospitalized for COVID-19 Still Report Significant Symptoms at Four Months Postdischarge. American Family Physician. 2021 2021/08//:206+.
Bell (Includes children)	Bell ML, Catalfamo CJ, Farland LV, Ernst KC, Jacobs ET, Klimentidis YC, et al. Post-acute sequelae of COVID-19 in a non-hospitalized cohort: Results from the Arizona CoVHORT. PLoS One. 2021;16(8):e0254347.
Bellan	Bellan M, Baricich A, Patrucco F, Zeppegno P, Gramaglia C, Balbo PE, et al. Long-term sequelae are highly prevalent one year after hospitalization for severe COVID-19. Sci Rep. 2021;11(1):22666.
Blanco	Blanco JR, Cobos-Ceballos MJ, Navarro F, Sanjoaquin I, Arnaiz de Las Revillas F, Bernal E, et al. Pulmonary long-term consequences of COVID-19 infections after hospital discharge. Clin Microbiol Infect. 2021;27(6):892-6.
Blomberg (Includes children)	Blomberg B, Mohn KG, Brokstad KA, Zhou F, Linchausen DW, Hansen BA, et al. Long COVID in a prospective cohort of home-isolated patients. Nat Med. 2021;27(9):1607-13.
Boglione	Boglione L, Meli G, Poletti F, Rostagno R, Moglia R, Cantone M, et al. Risk factors and incidence of long-COVID syndrome in hospitalized patients: does remdesivir have a protective effect? Qjm. 2022;114(12):865-71.
Boscolo-Rizzo (A)	Boscolo-Rizzo P, Guida F, Polesel J, Marcuzzo AV, Capriotti V, D'Alessandro A, et al. Sequelae in adults at 12 months after mild-to-moderate coronavirus disease 2019 (COVID-19). Int Forum Allergy Rhinol. 2021;11(12):1685-8.
Boscolo-Rizzo (B)	Boscolo-Rizzo P, Hummel T, Hopkins C, Dibattista M, Menini A, Spinato G, et al. High prevalence of long-term olfactory, gustatory, and chemesthesis dysfunction in post-COVID-19 patients: a matched case-control study with one-year follow-up using a comprehensive psychophysical evaluation. Rhinology. 2021;59(6):517-27.
Bozzetti	Bozzetti S, Ferrari S, Zanzoni S, Alberti D, Braggio M, Carta S, et al. Neurological symptoms and axonal damage in COVID-19 survivors: are there sequelae? Immunol Res. 2021;69(6):553-7.
Buonsenso	Buonsenso D, Munblit D, De Rose C, Sinatti D, Ricchiuto A, Carfi A, et al. Preliminary evidence on long COVID in children. Acta Paediatr. 2021;110(7):2208-11.
Buttery	Buttery S, Philip KEJ, Williams P, Fallas A, West B, Cumella A, et al. Patient symptoms and experience following COVID-19: results from a UK-wide survey. BMJ Open Respir Res. 2021;8(1).
Carfi	Carfì A, Bernabei R, Landi F. Persistent Symptoms in Patients After Acute COVID-19. Jama. 2020;324(6):603-5.
Carvalho-Schneider	Carvalho-Schneider C, Laurent E, Lemaignen A, Beaufils E, Bourbao-Tournois C, Laribi S, et al. Follow-up of adults with noncritical COVID-19 two months after symptom onset. Clin Microbiol Infect. 2021;27(2):258-63.
Cheng	Cheng D, Calderwood C, Skyllberg E, Ainley A. Clinical characteristics and outcomes of adult patients admitted with COVID-19 in East London: a retrospective cohort analysis. BMJ Open Respir Res. 2021;8(1).
Chevinsky	Chevinsky JR, Tao G, Lavery AM, Kukielka EA, Click ES, Malec D, et al. Late Conditions Diagnosed 1-4 Months Following an Initial Coronavirus Disease 2019 (COVID-19) Encounter: A Matched-Cohort Study Using Inpatient and Outpatient Administrative Data-United States, 1 March-30 June 2020. Clin Infect Dis. 2021;73(Suppl 1):S5-s16.
Clavario	Clavario P, De Marzo V, Lotti R, Barbara C, Porcile A, Russo C, et al. Cardiopulmonary exercise testing in COVID-19 patients at 3 months follow-up. Int J Cardiol. 2021;340:113-8.
COMEBAC Study Group	Writing Committee for the COMEBAC Study Group. Morin L, Savale L, Pham T, Colle R, Figueiredo S, Harrois A, et al. Four-Month Clinical Status of a Cohort of Patients After Hospitalization for COVID-19. Jama. 2021;325(15):1525-34.
Crankson	Crankson S, Pokhrel S, Anokye NK. Determinants of COVID-19-Related Length of Hospital Stays and Long COVID in Ghana: A Cross-Sectional Analysis. Int J Environ Res Public Health. 2022;19(1).
Cristillo	Cristillo V, Pilotto A, Cotti Piccinelli S, Zoppi N, Bonzi G, Gipponi S, et al. Age and subtle cognitive impairment are associated with long-term olfactory dysfunction after COVID-19 infection. J Am Geriatr Soc. 2021;69(10):2778-80.
D'Cruz	D'Cruz RF, Waller MD, Perrin F, Periselneris J, Norton S, Smith LJ, et al. Chest radiography is a poor predictor of respiratory symptoms and functional impairment in survivors of severe COVID-19 pneumonia. ERJ Open Res. 2021;7(1).
Desdiani	Desdiani D, Sutarto AP, Kharisma AN, Safitri H, Hakim AF, Rusyda SH. Sequelae in COVID-19 patients 3 months after hospital discharge or completion of self-isolation. Health Sci Rep. 2021;4(4):e444.
Divanoglou	Divanoglou A, Samuelsson APK, Sjödahl PER, Andersson C, Levi PR. Rehabilitation needs and mortality associated with the Covid-19 pandemic: a population-based study of all hospitalised and home-healthcare individuals in a Swedish healthcare region. EClinicalMedicine. 2021;36:100920.
Eggert (Includes children)	Eggert LE, He Z, Collins W, Lee AS, Dhondalay G, Jiang SY, et al. Asthma phenotypes, associated comorbidities, and long-term symptoms in COVID-19. Allergy. 2022;77(1):173-85.
Einvik	Einvik G, Dammen T, Ghanima W, Heir T, Stavem K. Prevalence and Risk Factors for Post-Traumatic Stress in Hospitalized and Non-Hospitalized COVID-19 Patients. Int J Environ Res Public Health. 2021;18(4).
Eloy	Eloy P, Tardivon C, Martin-Blondel G, Isnard M, Turnier PL, Marechal ML, et al. Severity of self-reported symptoms and psychological burden 6-months after hospital admission for COVID-19: a prospective cohort study. Int J Infect Dis. 2021;112:247-53.
Evans	Evans RA, McAuley H, Harrison EM, Shikotra A, Singapuri A, Sereno M, et al. Physical, cognitive, and mental health impacts of COVID-19 after hospitalisation (PHOSP-COVID): a UK multicentre, prospective cohort study. Lancet Respir Med. 2021;9(11):1275-87.
Faverio	Faverio P, Luppi F, Rebora P, Busnelli S, Stainer A, Catalano M, et al. Six-Month Pulmonary Impairment after Severe COVID-19: A Prospective, Multicentre Follow-Up Study. Respiration. 2021;100(11):1078-87.
Fernandez-de-Las-Penas (A)	Fernández-de-Las-Peñas C, Gómez-Mayordomo V, Cuadrado ML, Palacios-Ceña D, Florencio LL, Guerrero AL, et al. The presence of headache at onset in SARS-CoV-2 infection is associated with long-term post-COVID headache and fatigue: A case-control study. Cephalalgia. 2021;41(13):1332-41.
Fernandez-de-Las-Penas (B)	Fernández-de-Las-Peñas C, Gómez-Mayordomo V, de-la-Llave-Rincón AI, Palacios-Ceña M, Rodríguez-Jiménez J, Florencio LL, et al. Anxiety, depression and poor sleep quality as long-term post-COVID sequelae in previously hospitalized patients: A multicenter study. J Infect. 2021;83(4):496-522.
Fernandez-de-Las-Penas (C)	Fernández-de-Las-Peñas C, Gómez-Mayordomo V, García-Azorín D, Palacios-Ceña D, Florencio LL, Guerrero AL, et al. Previous History of Migraine Is Associated With Fatigue, but Not Headache, as Long-Term Post-COVID Symptom After Severe Acute Respiratory SARS-CoV-2 Infection: A Case-Control Study. Front Hum Neurosci. 2021;15:678472.
Froidure	Froidure A, Mahsouli A, Liistro G, De Greef J, Belkhir L, Gérard L, et al. Integrative respiratory follow-up of severe COVID-19 reveals common functional and lung imaging sequelae. Respir Med. 2021;181:106383.
Fu	Fu L, Fang Y, Luo D, Wang B, Xiao X, Hu Y, et al. Pre-hospital, in-hospital and post-hospital factors associated with sleep quality among COVID-19 survivors 6 months after hospital discharge: cross-sectional survey in five cities in China. BJPsych Open. 2021;7(6):e191.
Garcia-Abellan	García-Abellán J, Padilla S, Fernández-González M, García JA, Agulló V, Andreo M, et al. Antibody Response to SARS-CoV-2 is Associated with Long-term Clinical Outcome in Patients with COVID-19: a Longitudinal Study. J Clin Immunol. 2021;41(7):1490-501.
Garrigues	Garrigues E, Janvier P, Kherabi Y, Le Bot A, Hamon A, Gouze H, et al. Post-discharge persistent symptoms and health-related quality of life after hospitalization for COVID-19. J Infect. 2020;81(6):e4-e6.
Gautam	Gautam N, Madathil S, Tahani N, Bolton S, Parekh D, Stockley J, et al. Medium-Term Outcomes in Severely to Critically Ill Patients With Severe Acute Respiratory Syndrome Coronavirus 2 Infection. Clin Infect Dis. 2022;74(2):301-8.
Gerard	Gérard M, Mahmutovic M, Malgras A, Michot N, Scheyer N, Jaussaud R, et al. Long-Term Evolution of Malnutrition and Loss of Muscle Strength after COVID-19: A Major and Neglected Component of Long COVID-19. Nutrients. 2021;13(11).
Gherlone	Gherlone EF, Polizzi E, Tetè G, De Lorenzo R, Magnaghi C, Rovere Querini P, et al. Frequent and Persistent Salivary Gland Ectasia and Oral Disease After COVID-19. J Dent Res. 2021;100(5):464-71.
Ghosn	Ghosn J, Piroth L, Epaulard O, Le Turnier P, Mentré F, Bachelet D, et al. Persistent COVID-19 symptoms are highly prevalent 6 months after hospitalization: results from a large prospective cohort. Clin Microbiol Infect. 2021;27(7):1041.e1-.e4.
Glück	Glück V, Grobecker S, Tydykov L, Salzberger B, Glück T, Weidlich T, et al. SARS-CoV-2-directed antibodies persist for more than six months in a cohort with mild to moderate COVID-19. Infection. 2021;49(4):739-46.
González-Hermosillo	González-Hermosillo JA, Martínez-López JP, Carrillo-Lampón SA, Ruiz-Ojeda D, Herrera-Ramírez S, Amezcua-Guerra LM, et al. Post-Acute COVID-19 Symptoms, a Potential Link with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A 6-Month Survey in a Mexican Cohort. Brain Sci. 2021;11(6).
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Huang (A)	Huang Y, Pinto MD, Borelli JL, Asgari Mehrabadi M, Abrahim HL, Dutt N, et al. COVID Symptoms, Symptom Clusters, and Predictors for Becoming a Long-Hauler Looking for Clarity in the Haze of the Pandemic. Clin Nurs Res. 2022;31(8):1390-8.
Huang (B)	Huang L, Yao Q, Gu X, Wang Q, Ren L, Wang Y, et al. 1-year outcomes in hospital survivors with COVID-19: a longitudinal cohort study. Lancet. 2021;398(10302):747-58.
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Jacobson	Jacobson KB, Rao M, Bonilla H, Subramanian A, Hack I, Madrigal M, et al. Patients With Uncomplicated Coronavirus Disease 2019 (COVID-19) Have Long-Term Persistent Symptoms and Functional Impairment Similar to Patients with Severe COVID-19: A Cautionary Tale During a Global Pandemic. Clin Infect Dis. 2021;73(3):e826-e9.
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Points four and five related to the impact of different strains of SARS-CoV-2 and vaccination on prevalence estimates. Whilst we agree different strains of SARS-CoV-2 may have had differing effects on prevalence rates very few (if any) included studies included information on strains and therefore this was beyond the scope of our review. We agree that vaccination status is an important issue and previously acknowledge this within the manuscript “As of July 2022, over 12 billion vaccine doses have been administered globally; however, assessing the impact of vaccination status on Long Covid prevalence was beyond the scope of the current review. Future reviews should seek to investigate the prevalence of Long Covid across vaccination status and different variants of SARS-CoV-2.”

We would also like to take this opportunity to highlight that we did not previously include an acknowledgement to Keith Nockels, Academic Librarian at the University of Leicester for his invaluable help refining and running the various database searches.

Contributors

LLO, AR, CG and KK conceptualised the manuscript. All authors critically revised the manuscript for intellectual content. All authors had final responsibility for the decision to submit for publication.

Declaration of interests

KK is Chair of the Ethnicity Subgroup of the UK Scientific Advisory Group for Emergencies (SAGE) and Member of SAGE and also Chair of the National Long Covid working group which reports to the Chief Medical Officer.