Merge pull request #378 from cmu-delphi/another-survey-pub

Another survey citation

Author: sgratzl

content/covidcast/surveys.md

@@ -55,6 +55,7 @@ Our [National COVID Survey Dashboard]({{< relref "covidcast/survey-results" >}})
 - C. M. Zipfel, V. Colizza, and S. Bansal (2021). [The missing season: The impacts of the COVID-19 pandemic on influenza](https://doi.org/10.1016/j.vaccine.2021.05.049). *Vaccine*.
 - J. Lessler, M. K. Grabowski, K. H. Grantz, E. Badillo-Goicoechea, C. J. E. Metcalf, C. Lupton-Smith, A. S. Azman, and E. A. Stuart (2021). [Household COVID-19 risk and in-person schooling](https://doi.org/10.1126/science.abh2939). *Science* 372 (6545), 1092-1097.
 - Doerr, A.J. (2021). [Locked (Down) and Loaded (Language): Effect of Policy and Speech on COVID-19 Outcomes](https://doi.org/10.1177/15480518211012404). *Journal of Leadership & Organizational Studies*.
+- Fischer CB, Adrien N, Silguero JJ, Hopper JJ, Chowdhury AI, Werler MM (2021). [Mask adherence and rate of COVID-19 across the United States](https://doi.org/10.1371/journal.pone.0249891). PLoS ONE 16 (4), e0249891.
 - Bilinski, A., Emanuel, E., Salomon, J.A. and Venkataramani, A. (2021). [Better Late Than Never: Trends in COVID-19 Infection Rates, Risk Perceptions, and Behavioral Responses in the USA](https://doi.org/10.1007/s11606-021-06633-8). *Journal of General Internal Medicine*.
 - Molteni, E., Astley, C.M., Ma, W. et al. (2021). [Symptoms and syndromes associated with SARS-CoV-2 infection and severity in pregnant women from two community cohorts](https://doi.org/10.1038/s41598-021-86452-3). *Scientific Reports* 11, 6928.
 - Rebeiro, P., Aronoff, D, and Smith, M.K. (2021). [The Impact of State Mask-Wearing Requirements on the Growth of COVID-19 Cases, Hospitalizations, and Deaths in the United States](https://doi.org/10.1093/cid/ciab101). *Clinical Infectious Diseases*, ciab101.