Should individuals in the community without respiratory symptoms wear facemasks to reduce the spread of Covid-19? – Update 1
Note
|Published
We did a rapid review of evidence to inform a recommendation regarding people without respiratory symptoms wearing facemasks in the community to reduce the spread of Covid-19. We used an Evidence to Decision (EtD) framework to guide the process from reviewing the evidence to a recommendation. The present report is an update of a recommendation from June 2020 [NIPH 2020a].
Key message
We did a rapid review of evidence to inform a recommendation regarding people without respiratory symptoms wearing facemasks in the community to reduce the spread of Covid-19. We used an Evidence to Decision (EtD) framework to guide the process from reviewing the evidence to a recommendation. The present report is an update of a recommendation from June 2020 [NIPH 2020a].
There is evidence of a protective effect of medical facemasks against respiratory infections in community settings. Randomised trials from community settings indicate a small protective effect. There is no reliable evidence of the effectiveness of non-medical facemasks in community settings. There is likely to be substantial variation in effectiveness between products.
Potential undesirable effects of facemasks include the risks of incorrect use, a false sense of security (leading to relaxation of other interventions), and contamination of masks. In addition, some people experience problems breathing, discomfort, and problems with communication.
Since we published our first report and recommendation in June 2020, the incidence of Covid-19 has increased in Norway. In defined areas with a high incidence and risk of spread, use of facemasks has been recommended, or mandated. Surveys indicate that facemasks are currently accepted by the healthy population in Norway. However, the extent to which facemasks are used correctly and if use leads to a false sense of security is uncertain.
The most important criteria for our recommendation were the problem priority (the baseline risk and seriousness of the spread of Covid-19 in the community from people without respiratory symptoms) and the balance of desirable and undesirable effects.
Conditional recommendation for use of facemasks in the community
In situations where the incidence of Covid-19 is low and controlled, we do not recommend the use of facemasks by individuals without respiratory symptoms in the community who are not in close contact with people who are known or assumed to be infected.
In situations where the incidence is high, increasing or the spread is uncontrolled, either locally, regionally or nationally, use of facemasks should be considered even though study results of the protective effect vary greatly and the certainty of the evidence is low. A recommendation to use facemasks should be based on a risk assessment, not the incidence alone, and should be targeted to settings where distance cannot be kept indoors, including on public transport, and especially where contact tracing is difficult. Facemasks should only be recommended as an additional measure when the incidence cannot be controlled by less burdensome measures.
Medical facemasks or quality controlled non-medical facemasks with a documented filtration effect should be used. For personal protection, for example by people belonging to medical risk groups, only medical facemasks type II or IIR should be used.
If a recommendation to use facemasks is made, the community should be given information to ensure correct use and the risks should be explained, including the risks of a false sense of security and contamination of masks. The training should be tailored to the needs of different groups, including people with different levels of fluency in Norwegian and different socio-economic circumstances. There is some evidence that suggests information which emphasizes caring and fairness may improve compliance more than mandates that emphasize authority. Gender and age specific information may also increase compliance.
Facemasks should not replace other interventions such as physical distancing, avoiding situations where social distancing is not possible, hand washing, and use of disinfectants.
