Re: Face masks for the public during the covid-19 crisis
Dear Editor
We’ve got it wrong before. When car seat belts were introduced in the 1970’s death rates in pedestrians and back seat passengers increased because of speeding (1). When condoms are freely distributed to populations of young people it results in increased sexual risk taking behaviour and increased levels of transmission of sexually transmitted infections (2) . Higher levels of risk taking behaviour has been described with use of pre-exposure prophylaxis in HIV (3) .
Failure of a health promotion intervention because of risk taking happens when there is a perceived reduction in the danger associated with that activity, a confounder called risk compensation. Prof Greenhalgh and her colleagues are right to point this out (4) .
The proposal to introduce face masks for the public, while appearing a reasonable and pragmatic intervention, may give the public a false sense of reassurance. The use of face masks by the public may turn out to be a self-defeating intervention if it increases risk taking where social distancing and handwashing, both proven methods of reducing the spread of coronavirus, are ignored.
1. Richens J, Imire J, Copas A. Condoms and seat belts: the parallels and the lessons. Lancet 2000; 355: 400-403.
2. Cassell MM, Halperin DT, Shelton JD et al. Risk compensation: the Achilles' heel of innovations in HIV prevention? BMJ 2006; 332:605-7.
3. Holt M, Murphy DA. Individual Versus Community-Level Risk Compensation Following Preexposure Prophylaxis of HIV. Am J Public Health 2017; 107 (10): 1568-71.
4. Greenhalgh T, Schmid MB, Czypionka T. et al, Face masks for the public during the Covid-19 crisis
BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1435 : BMJ 2020;369:m1435
Rapid Response:
Re: Face masks for the public during the covid-19 crisis
Dear Editor
We’ve got it wrong before. When car seat belts were introduced in the 1970’s death rates in pedestrians and back seat passengers increased because of speeding (1). When condoms are freely distributed to populations of young people it results in increased sexual risk taking behaviour and increased levels of transmission of sexually transmitted infections (2) . Higher levels of risk taking behaviour has been described with use of pre-exposure prophylaxis in HIV (3) .
Failure of a health promotion intervention because of risk taking happens when there is a perceived reduction in the danger associated with that activity, a confounder called risk compensation. Prof Greenhalgh and her colleagues are right to point this out (4) .
The proposal to introduce face masks for the public, while appearing a reasonable and pragmatic intervention, may give the public a false sense of reassurance. The use of face masks by the public may turn out to be a self-defeating intervention if it increases risk taking where social distancing and handwashing, both proven methods of reducing the spread of coronavirus, are ignored.
1. Richens J, Imire J, Copas A. Condoms and seat belts: the parallels and the lessons. Lancet 2000; 355: 400-403.
2. Cassell MM, Halperin DT, Shelton JD et al. Risk compensation: the Achilles' heel of innovations in HIV prevention? BMJ 2006; 332:605-7.
3. Holt M, Murphy DA. Individual Versus Community-Level Risk Compensation Following Preexposure Prophylaxis of HIV. Am J Public Health 2017; 107 (10): 1568-71.
4. Greenhalgh T, Schmid MB, Czypionka T. et al, Face masks for the public during the Covid-19 crisis
BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1435 : BMJ 2020;369:m1435
Competing interests: No competing interests