Results from a correlation between mask use and the effects of Covid-19 in Europe indicate that countries with high levels of mask compliance did not perform better than those with low mask use in the six-month period encompassing the second European wave of Covid-19.
The study determined that the correlation between mask use and Covid-19 numbers was null or positive, depending on the subgroup of countries and the type of outcomes (cases or deaths). The positive correlations were stronger in the Western than in Eastern European countries.
These results indicate that countries with high levels of mask compliance did not perform better than those with low mask use in the six-month period encompassing the second European wave of Covid-19.
The accuracy of these measures varied between different countries and therefore resulted in different proportions of mask compliance, ranging from 5% to 95%. This heterogeneity in mask use among neighboring countries provided an ideal opportunity to test the effect of this non-pharmaceutical intervention on the progression of Covid-19 epidemics.
While it is not appropriate to draw definitive conclusions from this observational analysis alone, the lack of negative correlations between mask use and the number of Covid-19 cases and deaths suggests that the widespread use of masks at a time when effective intervention was most need, was not able to reduce the transmission of Covid-19.
Results
Weak positive correlations were observed between mask compliance and morbidity (cases/millions) or mortality (deaths/millions) in each country.
A Spearman classification test was applied to quantify the correlation between mask use, cases and deaths.
The positive correlation between mask use and cases was not statistically significant, while the correlation between mask use and deaths was positive and significant.
The correlation between masks and deaths was considerably higher in the West than in Eastern European countries.
Correlations did not change significantly when the seven countries with populations over 20 million were excluded from the analysis (rho cases = 0.129 (p = 0.513); rho deaths = 0.375 (p = 0.049)).
Analyzes of other subgroups were also evaluated, such as countries with populations of less than six million, greater than 10 million, or greater than 15 million. None of these tests provided negative correlations between mask use and cases/deaths.
| Country (Country) | Average mask usage (1* ) | Cases/million (Cases/million) | Deaths/million (Deaths/million) |
| Albania | 53% | 40990 | 679 |
| Bosnia and Herzegovina | 40% | 43078 | 1738 |
| Bulgaria | 55% | 46405 | 1784 |
| Croatia | 29% | 60039 | 1334 |
| Czech Republic | 52% | 137494 | 2418 |
| Hungary | 77% | 64704 | 2064 |
| North Macedonia | 67% | 52048 | 1413 |
| Poland | 72% | 57966 | 1315 |
| Romania | 81% | 42898 | 1121 |
| Serbia | 54% | 64829 | 521 |
| Slovakia | 76% | 128326 | 1779 |
| Slovenia | 69% | 101198 | 1879 |
| Belarus | 55% | 25595 | 149 |
| Estonia | 64% | 78525 | 639 |
| Latvia | 64% | 52493 | 972 |
| Lithuania | 74% | 75664 | 1252 |
| Republic of Moldova | 66% | 48045 | 1102 |
| Ukraine | 67% | 34298 | 686 |
| Austria | 55% | 56237 | 959 |
| Belgium | 71% | 66905 | 1135 |
| Denmark | 14% | 34942 | 312 |
| Finland | 46% | 12252 | 100 |
| France | 76% | 58354 | 928 |
| Germany | 57% | 29671 | 791 |
| Greece | 84% | 23722 | 745 |
| Ireland | 71% | 40270 | 587 |
| Italy | 91% | 54310 | 1223 |
| Netherlands | 51% | 68009 | 596 |
| Norway | 29% | 15340 | 75 |
| Portugal | 84% | 70056 | 1397 |
| Spain | 95% | 55480 | 968 |
| Sweden | 5% | 70356 | 759 |
| Switzerland | 53% | 62669 | 927 |
| United Kingdom | 62% | 57689 | 1363 |
| Northern Ireland | 68% | 54567 | 1039 |
| Shapiro-Wilk p-value (2*) | 0.056 | 0.004 | 0.693 |
Table 1: Proportion of mask use and the number of COVID-19 cases and deaths per million over autumn and winter 2020-2021 (October 1 to March 31) in Europe.
(1*) Percentage of the population that reports always wearing a mask when leaving home.
(2*) Shapiro-Wilk test for normality.
Limitations
Some limitations of this study are recognized, such as the fact that in some countries (not in others) it can be said that increasing levels of infection led to mask use, resulting in higher levels of mask use in countries with already high transmission rates.
Conclusions
The authors draw two main conclusions:
- “While cause-and-effect conclusions could not be drawn from this observational analysis, the lack of negative correlations between mask use and COVID-19 cases and deaths suggests that widespread mask use at a time when intervention was most needed effective, i.e. during the strong autumn-winter 2020-2021 peak, it was not able to reduce COVID-19 transmission.”
- “Furthermore, the moderate positive correlation between mask use and deaths in Western Europe also suggests that universal mask use may have had harmful and unintended consequences.”
Read too:
