The United Nations did not recommend mask wearing for the overall population before June 2020. There were insufficient clinical trials in real-world conditions to prove their usefulness, and reservations were expressed over counter-productive behaviour that a “false feeling of security” might provoke. But today, in poorer countries that lack access to anti-COVID-19 vaccines, this type of non-restrictive precautionary measure is crucial.
In order to evaluate the importance of mask wearing, American and Australian researchers (from the Universities of Dale and of Deakin) carried out trials on 342 183 people spread over 600 villages in Bangladesh between November 2020 and April 2021. In this country the impact of COVID-19 has been largely underestimated. The aim was to judge the effectiveness of various strategies to persuade the general population (and not just ill people) to wear masks, and to measure the effect on seroprevalence and COVID-19 symptoms. Large-scale distribution of masks, accompanied by an awareness campaign, was organised in places where the public meet (markets, mosques, council meetings), and different strategies were employed.
The results showed that personal delivery with individual advice increased mask wearing by 28,8% (51 357 people), an effect which lasted for at least 4 months after the campaign. In total, 42,3% of people wore masks, a very positive figure. Symptomatic cases of COVID-19 were reduced by 11,6%. Cases where individuals were symptomatic and seropositive for SARS-CoV-2 were reduced by 9,5% in total, but by 35% in persons older than 60 (no clear reasons for this were found).
In addition, people who wore masks proved to be more responsive to risk prevention and tended to better respect social distancing rules (+5,1%). Compared with surgical masks, the effects of cloth masks on the incidence of symptoms was lower, although they were accepted just as well. Where masks were simply given out, without any information or advice, this led to less good results. Verbal commitments given in public, encouragement by village leaders, SMS reminder messages (twice a week) and altruistic messages also proved ineffective.
Person to person distribution with individual guidance for mask usage clearly helped to increase their utilisation in rural areas of Bangladesh. This approach contradicts certain expectations, and the results are therefore important in helping to design an effective public health programme in this country of 167 million inhabitants. Applied on a large scale, it could prove just as effective in saving lives as other humanitarian programmes that cost a lot more. The authors are currently working with the government to apply these policies in 37 priority districts. The model has also been adopted in Pakistan, Indian and Nepal. It could also prove useful in making people aware of the dangers of alcohol and tobacco, and in promoting hygiene measures.