In April, when mask mandates were being instituted, a prominent doctor colleague kept questioning, in social media, the mandated use of masks, saying there was no evidence they worked.
It is well known that masks work in hospitals to prevent transmission of infections from patients to doctors and patients to other patient . What was not clear when the pandemic started, is whether they would also work in the general population.
Let us look again at the hierarchical model of tests and interventions that I had written about earlier.
Every diagnostic test or treatment or preventive intervention needs to be proven to work in real-life settings. Just because something works in the laboratory does not mean it would necessary work with people at large and changes outcomes.
Once it was accepted that SARS-CoV-2 virus spreads through aerosols , it was intuitive that masks would make a difference . But, while masks may work in the laboratory and in case reports, they need to be proven to work in real-life settings.
This review article by Jeremy Howard and his colleagues shows the evidence till date, which includes historical data, modeling data, case reports and a few comparative studies . And just a couple of weeks ago, came this study by Benjamin Rader and his colleagues, who looked at self-reported mask use in a large US-based population compared with infection rates in the community, and showed that masks along with physical distancing make a big difference .
In short, masks work.
Vaccines work . Over the last 200 years, apart from improved sanitation, clean water and better nutrition, it is the use of vaccines that has helped reduce disease and improve longevity. Check out this cool vaccine timeline.
Covid-19 vaccines have shown variable efficacy in trials, but recent real-life data from Israel  has shown that it works.
Let us look again at Frieden’s pyramid that I had described earlier.
Ideally, mask and vaccine mandates should both make a difference at the level of Tier II. Mask mandates are easier to create than vaccine mandates, though how effectively they are imposed depends upon the political system, the pattern of Government and the ideology of the populace. In a country like India for example, it has been much easier to enforce mask-mandate compliance than in the US and that may be a major reason why India is doing better currently with Covid-19 infection rates than many other countries including the UK and the US.
A vaccine mandate would also be much more difficult, both ethically and legally to enforce in such circumstances, though mandates do exist for other forms of vaccination . Irrespective of a mandate, since there is considerable effort needed to get the vaccine administered to individuals (Tier III), the short and medium term impact of vaccination would necessarily be less than that of universal masking (Tier II), a fact that many people in their exuberance of getting a vaccine may not understand.
A friend of mine invited us recently to their house for an indoor party. My wife and I have both received our first dose of the Oxford vaccine, but we are still circumspect about any activity indoors with people apart from those we live with, which involves us having to pull our masks down. When we told them that we would come for a very short time and not have food, their response was “but you have received the vaccine…”. Irrespective of whether we are vaccinated or not, masks and physical distancing and hygiene and sanitation are not going anywhere .
As we see in this diagram, vaccine and masks together would be the ideal situation, no vaccine and no masks, the worst, masks without vaccine would still work well, and vaccine without masks…all experts say this is not an acceptable option.
And though this was published in July, this cartoon by Malaka Gharib still holds true, vaccine or no vaccine.
1. MacIntyre CR, Chughtai AA, Rahman B, Peng Y, Zhang Y, Seale H, et al. The efficacy of medical masks and respirators against respiratory infection in healthcare workers. Influenza Other Respi Viruses. 2017 Nov;11(6):511–7.
3. Leung NHL, Chu DKW, Shiu EYC, Chan K-H, McDevitt JJ, Hau BJP, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med. 2020 May;26(5):676–80.
4. Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, van der Westhuizen H-M, et al. An evidence review of face masks against COVID-19. Proc Natl Acad Sci USA. 2021 Jan 26;118(4):e2014564118.
5. Rader B, White LF, Burns MR, Chen J, Brilliant J, Cohen J, et al. Mask-wearing and control of SARS-CoV-2 transmission in the USA: a cross-sectional study. The Lancet Digital Health. 2021 Jan;S2589750020302934.
8. Gostin LO, Salmon DA, Larson HJ. Mandating COVID-19 Vaccines. JAMA [Internet]. 2020 Dec 29 [cited 2021 Feb 7]; Available from: https://jamanetwork.com/journals/jama/fullarticle/2774712
9. Mermel LA. The future of masking. Infect Control Hosp Epidemiol. 2021 Jan 28;1–1