. 2021 Oct 22;6:126. Originally published 2021 May 24. [Version 3] doi: 10.12688/wellcomeopenres.16855.3

Table 1. Sources used in the case studies.

Setting	Focus	Sources analysed for this case (listed in date order)
International policy context	Early and continuing alignment of WHO policy with droplet mode of transmission	A1. WHO guidance on biological and chemical weapons (2004) ²⁵ A2. Transcript of WHO inaugural press conference on Covid-19 (11 ^th Feb 2020) ⁷⁵ A3. WHO interim guidance on use of personal protective equipment by healthcare staff (27 ^th Feb 2020) ⁹¹ A4. WHO video for the lay public on how to protect yourself against Covid-19 (28 ^th Feb 2020) A5. WHO Tweet “Covid-19 is not airborne” (28 ^th Mar 2020) A6. Asian Development Bank report on global PPE supply (April 2020) ²⁶ A7. Transcript of WHO press conference (5 ^th June 2020) ⁷⁶ A8. Journal article ( open letter to policymakers on behalf of 238 aerosol scientists) ‘It is time to address airborne transmission of coronavirus disease 2019 (COVID-19)’ by Morawska and Milton (6 ^th July 2020) ³ A9. Press article by Krisch on source A8 reporting interviews with WHO senior staff and committee members ‘Is the coronavirus airborne?’ (7 ^th July 2020) ³⁰ A10. News feature by Lewis in Nature ‘Mounting evidence suggests coronavirus is airborne’ (8 ^th July 2020) ³¹ A11. WHO Scientific Brief ‘Transmission of SARS-CoV-2’ (9 ^th July 2020) ³² A12. Peer-reviewed article ‘Use of medical face masks’ by Conly et al. (6 ^th August 2020) ⁷ A13. WHO public information site ‘Coronavirus disease: Advice for the public’ (13 ^th Oct 2020) ⁵² A14. Letter to editor critiquing source A10 ‘Scientific evidence supports aerosol transmission of SARS-CoV-2’ by MacIntyre and Ananda-Rajah (18 ^th Dec 2020) ³⁶ A15. Blog by Professor Raina MacIntyre ‘The hijacking of public health’ (5 ^th Jan 2021) ⁹² A16. WHO living clinical guideline on Covid-19, with linked biographies of guideline authors (updated 25 ^th January 2021) ³⁹ A17. WHO guidance ‘ Roadmap to improve and ensure good indoor ventilation in the context of COVID-19’ (5 ^th Mar 2021) ³⁸ A18. Paper launching WHO’s ‘clean your hands’ campaign led by Prof Allegranzi et al. (17 ^th Mar 2021) ²⁹ A19. Evidence summary (preprint) ‘SARS-CoV-2 and the role of airborne transmission [version 1]’ by Heneghan et al. (31 ^st March 2021) A20. WHO document ‘ Update on WHO COVID-19 guidelines development’ (7 ^th April 2021) A21. Video of panel discussion between aerosol scientist (Prather), infectious disease epidemiologist (Fisman) and chair of WHO IPC R&D working group (Conly) at University of Calgary, Canada (9 ^th April 2021) A22. Royal College of Nursing Infection Prevention and Control Network website (undated).
UK	Ventilation and staff protection in healthcare settings	B1. COVID-19 Infection Prevention and Control (IPC) guidance (UK) (updated 21 ^st Jan 2021) ⁴¹ B2. Antimicrobial Resistance and Healthcare Associated Infection (ARHAI) rapid review on COVID-19 (v 11, updated 5 ^th Feb 2021) ⁴² B3. Open letter to UK Prime Minister (led by Royal College of Nursing) on protecting healthcare workers (19 ^th Feb 2021) ⁴⁰ B4. Independent evidence review of guidelines for infection prevention and control in UK hospitals by Gould and Purssell, commissioned by Royal College of Nursing (28 ^th Feb 2021) ⁴³ B5. Radio interview Good Morning Scotland (2 ^nd Mar 2021) (transcript available from authors) B6. Public Health England guidance on ventilation of indoor spaces (5 ^th Mar 2021) ⁴⁴ B7. Blog by Professor Alison Leary ‘Why does healthcare reject the precautionary principle?’ ⁹³
Canada	Ventilation and masks in schools (British Colombia) and staff protection in healthcare settings (Quebec)	C1. Tweet from British Colombia Centre for Disease Control @CDCofBC (11 ^th Feb 2020) “this is not an airborne virus”. C2. News report by Kotyk ‘“Absolutely no evidence” that COVID is airborne’ (1 ^st June 2020) C3. News report by Lindsay ‘Controversy over airborne transmission of Covid-19’ (20 ^th July 2020) C4. British Colombia Teachers’ Federation news release ‘ BCTF files application with the Labour Relations Board over COVID-19 health and safety concerns’ (18 ^th September 2020) C5. British Colombia Teachers’ Federation. Brief for the Minister of Education, the Honourable Jennifer Whiteside. (17 ^th Dec 2020) ⁹⁴ C6. British Colombia Centre for Disease Control: How it [COVID-19] spreads (5 ^th Jan 2021) ⁴⁶ C7. British Colombia Nurses’ Union web report ‘ BCCDC Now Recognizes Airborne Transmission of COVID-19’ (8 ^th Jan 2021) C8. British Colombia Centre for Disease Control: ‘Personal Protective Equipment’ (27 ^th Jan 2021) ⁹⁵ C9. British Colombia Centre for Disease Control: ‘ COVID-19 Public Health Guidance for K-12 Schools’ (4 ^th Feb 2021) ¹⁰ C10. British Colombia Teachers’ Federation news release ‘ Changes to K–12 COVID-19 guidelines include some important positive steps, but more can be done’ (4 ^th Feb 2021) C11. News report by Brend ‘ School officials order windows screwed shut’ (20 ^th Feb 2021) C12. News report by Migdal ‘ 4 Takeaways from Dr Bonnie Henry’s New Book’ (12 ^th March 2021). C13. News report by Radio-Canada ‘ Le personnel médical en CHSLD veut davantage de protection’ (20 ^th Apr 2020) C14. Lafrenière, M. Le CIUSSS et le lavage des mains: « extrêmement petit de la part de la direction». newspaper article in Le Nouvelliste. (2020, Mardi 28th April 2020). C15. News report by Radio Canada (14th May 2020) Tous les résidents du CHSLD Vigi Mont- Royal ont contracté le virus. C16. Paré, I. Hécatombe chez les travailleurs de la santé. newspaper article in Le Devoir. (15th May 2020). C17. Public Health Ordonance : Arruda, H. (8 ^th June 2020). Ordonnance du directeur national de santé publique concernant le port des équipements de protection respiratoires et oculaires . Québec: Ministère de la Santé et des Services sociaux du Québec. C18. News report by La Presse canadienne (10th July 2020). https://ici.radio-canada.ca/ nouvelle/1718984/restriction-masque-n95-covid-coronavirus-cour-contestation C19. Paré, I. newspaper article in Le Devoir. (13th July 2020). Les infirmières contestent en cour le recours «abusif» à l'arrêté dictant leurs conditions de travail C20. Paré, I. newspaper article in Le Devoir (16th October 2020). Québec n’aura plus besoin de rationner les masques N95. C21. News report by M. Meloche-Holubowski (16 ^th February 2021) https://ici.radio-canada. ca/nouvelle/1768418/10000-morts-deces-covid-quebec-pandemie-covid-coronavirus C22. Legal judgement from Quebec court adjudicating between nurses’ unions and Public Health Institute of Quebec. (23 ^rd Mar 2021) C23. News report by Radio Canada (15th April 2021) La CNESST invitée à revoir sa position sur le port du masque N95 en zone tiède https://ici.radio-canada.ca/nouvelle/1785276/ directives-obligation-apr-patients-cas-tiedes-covid-19
Japan	Early implementation of ‘3Cs’ public information campaign	D1. Report from national expert meeting of Novel Coronavirus Control Team (Office of Japanese Prime Minister, 9th March 2020) ⁵¹ D2. ‘3Cs’ policy information poster (28th March 2020) ⁹⁶ D3. Speech by Japanese Prime Minister Shinzo Abe (7th April 2020) ⁹⁷ D4. Covid-19 update from Government of Japan (7th April 2020) ⁹⁸ D5. Academic paper on COVID-19 in Japan by Shimizu and Nigita (23rd Oct 2020) ⁴⁹ D6. Press article by Du ‘ This virus expert saved Japan from the worst of COVID-19. But has the magic worn off?’ (20 ^th November 2020) ⁵³ D7. Academic paper on Japan’s public health centers by Imamura et al. (18th Dec 2020) ⁵⁰