Is it really time to ditch the mask?

Dear Editor

Hrzic et al. are concerned that voluntary mask use instead of forced mask use in some public settings like public transport has the potential to insufficiently protect people’s health by allowing COVID-19 to spread more easily [1]. One relevant aspect, however, was not taken into account. At the beginning of the pandemic in 2020 the population was considered to be immunological naïve to COVID-19 resulting partly in drastic public health measures such as lockdowns with the aim to reduce the spread of SARS-CoV-2.

The situation, however, has changed substantially. 72.8% of the population in the European Union (as of 8th September 2022) and 67.5% in the United States (as of 31st August 2022) are fully vaccinated [2][3]. In addition, a relevant proportion of the population has gained natural immunity after an infection with SARS-CoV-2. For example, 112 of 160 unvaccinated pupils (70.0%) and 23 of 34 unvaccinated teachers (67.6%) in Saxony were reported to be seropositive in May 2022 (anti-spike IgG) [4]. An intersection of both groups even has hybrid immunity against COVID-19 providing the best possible long-term immunity [5]. In Germany, 95% of the population have antibodies against the S-antigen already [6]. As a consequence, the majority of the populations is not immunological naïve anymore resulting in a substantial decrease of severe COVID-19 cases [7].

In 2022 the omicron variant of concern (VOC) became the dominant SARS-CoV-2 variant worldwide. It is characterized by a lower pathogenicity and a higher transmissibility [8]. Importantly, the omicron lineages BA.4 and BA.5 were described to be more easily evading immunity generated by previous lineages including Omicron lineage BA.1 [9]. But nevertheless, the proportion of severe COVID-19 cases caused by omicron is low compared to previous VOCs such as delta [7].

SARS-CoV-2 poses still a relevant risk for severe COVID-19 among the elderly, the obese and patients with known comorbidities [10]. The low burden of severe disease outside these risk groups does not justify mandated general control measures for the entire population anymore as well as testing for COVID-19 in the asymptomatic population groups. The vulnerable population at risk can be protected by vaccination, metaphylactic antiviral treatment and count on a reliable health care system. In addition, non-pharmaceutical measures such as face masks or physical distancing can be used voluntarily. Mandating specific measures to the entire population cannot be justified anymore, such as the use of FFP2 respirators in long distance trains and buses as stipulated by the updated infection control act in Germany [11], especially because its beneficial effect on viral respiratory tract infections is doubtful [12]. We think that it is time to accept also in Germany that COVID-19 is becoming endemic as done in many other European countries such as the UK, Denmark and France.

Control efforts should now be confined to the prevention of severe COVID-19 among the most vulnerable population [13], an approach previously described as focussed protection. These include the application of routine hygienic measures against SARS-CoV-2 similar to other comparable respiratory infections in hospitals and other health care settings. They do also not preclude the government recommending specific preventive measures to the population at large. But it is now time to let the general population decide for themselves which measures they want to use for their self-protection against COVID-19.

Competing interests
PW, KS, GA, AR and GK have no conflicts of interest. JSC declare that the following conflicts of interest may exist with regard to the content of this letter, which may result from an employment relationship, a shareholding, a consultancy activity or grants for research projects, lectures or other activities in the last five years: PerkinElmer, BASF, Roche, Diasorin, Sanofi, Takeda, AstraZeneca, Pfizer, and Sonic Healthcare.

The views expressed here are those of the authors and do not necessarily reflect those of their universities.

Author Contribution statement
All authors had the idea to write the letter. GK prepared the first draft, the other authors added relevant aspects and citations and thereby contributed to various aspects of the text.

References
[1] Hrzic R, Peixoto VR, Mason-Jones AJ, McCallum A. Is it really time to ditch the mask? BMJ 2022;377:o1186. https://doi.org/10.1136/BMJ.O1186.
[2] European Centre for Disease Prevention and Control. COVID-19 Vaccine Tracker 2022. https://vaccinetracker.ecdc.europa.eu/public/extensions/COVID-19/vaccine... (accessed September 8, 2022).
[3] CDC. COVID Data Tracker: Vaccinations in the US 2022. https://covid.cdc.gov/covid-data-tracker/#vaccinations_vacc-total-admin-... (accessed September 8, 2022).
[4] Armann JP, Blankenburg J, Czyborra P, Doenhardt M, Horst T, Schneider J, et al. SARS-CoV-2 immunity gap among schoolchildren and teachers in the summer of 2022. Dtsch Arztebl Int 2022:in press. https://doi.org/10.3238/ARZTEBL.M2022.0307.
[5] Sette A, Crotty S. Immunological memory to SARS-CoV-2 infection and COVID-19 vaccines. Immunol Rev 2022:in press. https://doi.org/10.1111/IMR.13089.
[6] Lange B, Jäger VK, Rücker V, Harries M, Hassenstein MJ, Holt I Von, et al. 2. Interimsanalyse des IMMUNEBRIDGE- Projektes zur Kommunikation von vorläufigen Ergebnissen an das Modellierungsnetz für schwere Infektionskrankheiten 2022. https://www.bmbf.de/SharedDocs/Downloads/de/2022/20221013-zwischenberich....
[7] RKI. Wöchentlicher Lagebericht des RKI zur Coronavirus-Krankheit-2019 (COVID-19) 01.09.2022 – AKTUALISIERTER STAND FÜR DEUTSCHLAND 2022. https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus/Situationsb... (accessed September 8, 2022).
[8] Bálint G, Vörös-Horváth B, Széchenyi A. Omicron: increased transmissibility and decreased pathogenicity. Signal Transduct Target Ther 2022;7:151. https://doi.org/10.1038/S41392-022-01009-8.
[9] Bahadur Shrestha L, Foster C, Rawlinson W, Tedla N, Bull RA, Rowena Bull CA. Evolution of the SARS-CoV-2 omicron variants BA.1 to BA.5: Implications for immune escape and transmission. Rev Med Virol 2022:in press. https://doi.org/10.1002/RMV.2381.
[10] Skarbinski J, Wood MS, Chervo TC, Schapiro JM, Elkin EP, Valice E, et al. Risk of severe clinical outcomes among persons with SARS-CoV-2 infection with differing levels of vaccination during widespread Omicron (B.1.1.529) and Delta (B.1.617.2) variant circulation in Northern California: A retrospective cohort study. Lancet Reg Heal Am 2022;12:100297. https://doi.org/10.1016/J.LANA.2022.100297.
[11] Deutscher Bundestag. Bericht des Ausschusses für Gesundheit (14. Ausschuss) 2022. https://dserver.bundestag.de/btd/20/033/2003328.pdf (accessed September 8, 2022).
[12] Jefferson T, Del Mar CB, Dooley L, Ferroni E, Al Ansari LA, Bawazeer G, et al. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane Database Syst Rev 2020:CD006207. https://doi.org/10.1002/14651858.CD006207.pub5.
[13] Walger P, Antes G, Exner M, Stöhr K, Popp W, Alefelder C, et al. Pandemiemanagement – Strategiewechsel notwendig und überfällig. Monit Versorgungsforsch 2022;15:80–5. https://doi.org/10.24945/MVF.05.22.1866-0533.2450.