Effects of Social Distancing and Lockdown Protocols on Fatality Rates of COVID-19 in the U.S. during the First Year of the Pandemic.





COVID-19, Phase Transition, New York, Washington, Kansas, Texas, California, Florida, Source: (MeSH-NLM).


Background: SARS-CoV-2, the coronavirus strain responsible for the COVID-19 pandemic, can lead to respiratory diseases ranging in severity. In the early stages, each U.S. state implemented a transition or “phasing” policy that included varying degrees of safety protocols. This allowed the states to slowly reopen while controlling transmission. The initial lockdown was observed to help suppress the pandemic, and our study aimed to determine if there was a correlation between fatality rates and the phase transitions across the states.

Methods: Six states from regions with different caseloads were chosen for this study: Florida, California, New York, Washington, Kansas, and Texas. Incidence and mortality rate of COVID-19 were obtained from their respective government websites, allowing case fatality rates to be calculated and compared using Bayesian logistic mixed models.

Results: When examining the fatality rates across phases grouped by state, there was a downward trend with each transition except in Texas. However, when the states were combined the overall downward trend was clear, with a median fatality rate of 0.039 in phase 0 dropping to 0.010 by phase 4.

Conclusion: Implemented safety protocols and phase transitions were shown to assist in controlling the spread of COVID-19 as the states re-opened. Differences in fatality rates throughout the U.S. can likely be explained by how disciplined each state was with quarantine requirements and social distancing policies. This allowed certain states to control the infectious spread more efficiently than others, thus allowing the states to progress through the phase transitions at different rates.


Baron S. Medical Microbiology. 4th Edition. Galveston (TX): University of Texas Medical ranch at Galveston; 1996.

World Health Organization. Director-General's remarks at the media briefing on 2019-nCoV on 11 February 2020. Available from: http://www.who.int/dg/speeches/detail/who-director-general-s-remarks-at-the-media-briefing-on-2019-ncov-on-11-february-2020. Last updated Feb 11, 2020; cited Aug 2, 2021.

Wang C, Horby PW, Hayden FG, Gao GF. A novel coronavirus outbreak of global health concern. Lancet. 2020;395(10223):470-3.

Pfizer. Our Path to Developing the Pfizer-BioNTech COVID-19 Vaccine. Available from: https://www.pfizer.com/science/coronavirus/vaccine/rapid-progress. Cited Aug 2, 2021.

Moderna. Moderna’s Work on our COVID-19 Vaccine. Available from: https://www.modernatx.com/modernas-work-potential-vaccine-against-covid-19. Cited Aug 2, 2021.

Johnson & Johnson. Johnson & Johnson COVID-19 Vaccine Authorized by U.S. FDA For Emergency Use – First Single-Shot Vaccine in Fight Against Global Pandemic. Available from: https://www.jnj.com/johnson-johnson-covid-19-vaccine-authorized-by-u-s-fda-for-emergency-usefirst-single-shot-vaccine-in-fight-against-global-pandemic. Last updated Feb 27, 2021; cited Aug 2, 2021.

Office of the Texas Governor. Governor Abbott Announces Phase One To Open Texas, Establishes Statewide Minimum Standard Health Protocols. Available from: https://gov.texas.gov/news/post/governor-abbott-announces-phase-one-to-open-texas-establishes-statewide-minimum-standard-health-protocols. Last updated Apr 27, 2020; cited Aug 2, 2021.

The New York Times. What Restrictions on Reopening Remain in New York?. Available from: https://www.nytimes.com/article/new-york-phase-reopening.html. Last updated May 1, 2021; cited Aug 2, 2021.

Click Orlando. Here’s what to expect as Florida enters phase 2 of reopening. Available from: https://www.clickorlando.com/news/local/2020/05/12/heres-what-to-expect-when-florida-enters-phase-2-of-reopening/. Last updated Jun 10, 2020; cited Aug 2, 2021.

NOWCAST Wesh 2 News. What Phase 3 means for Disney, Universal theme parks. Available from: https://www.wesh.com/article/phase-3-disney-universal-theme-parks/34198078. Last updated Sept 28, 2020; cited Aug 2, 2021.

Atalan, A. Is the lockdown important to prevent the COVID-19 pandemic? Effects on psychology, environment and economy-perspective. Ann Med Surg (Lond). 2020;56:38-42.

Centers for Disease Control and Prevention. COVID Data Tracker. Available from: https://covid.cdc.gov/covid-data-tracker/?fbclid=IwAR2_kXL_ec27TD81bZuz23_WYZAclOOh-c3qbF9-HwOENqVl86nP6U7EVc0#cases_casesper100k. Cited Jan 15, 2021.

Washington State Coronavirus Response (COVID-19). Available from: https://www.coronavirus.wa.gov/. Cited 2021 Apr 1, 2021.

Novel Coronavirus. Available from: https://www.coronavirus.wa.gov/. Cited Apr 1, 2021.

Florida COVID-19 Response. Available from: https://floridahealthcovid19.gov/. Cited Apr 1, 2021.

Kansas Department of Health and Environment. Available from: https://www.coronavirus.kdheks.gov/. Cited Apr 1, 2021.

California Department of Public Health. Available from: https://cdph.ca.gov/covid19. Cited Apr 1, 2021.

Texas Health and Human Services. Available from: https://www.dshs.texas.gov/coronavirus/. Cited Apr 1, 2021.

Goodrich, B, Gabry J, Ali, Brilleman S. rstanarm: Bayesian applied regression modelingvia Stan. 2020. R package version 2.19.3 https://mc-stan.org/rstanarm.

Makowski, D, Ben-Shachar, MS, Annabel Chen, SH, Lüdecke, D. Indices of Effect Existence and Significance in the Bayesian Framework. Front Psychol. 2019;10:2767.

Vehtari, A, Gelman, A, Simpson, D, Carpenter, B, Bürkner, P-C. Rank-Normalization, Folding, and Localization: An Improved Ȓ for Assessing Convergence of MCMC (with Discussion). Bayesian Anal. 2021;16(2):667-718.

Bürkner, PC. brms: An R Package for Bayesian Multilevel Models using Stan. J Stat Softw. 2017;80(1):1-28.

Gharaibeh, A, Koppikar, S, J Bonilla-Escobar, F. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) in the International Journal of Medical Students. Int J Med Stud. 2014;2(2):36–7.

Brihn, A, Chang, J, OYong, K, Balter, S, Terashita, D, Rubin, Z, Yeganeh, N. Diagnostic Performance of an Antigen Test with RT-PCR for the Detection of SARS-CoV-2 in a Hospital Setting – Los Angeles County, California, June-August 2020. MMWR Morb Wkly Rep. 2021;70(19):702-6.

Clerici, B, Muscatello, A, Bai, F, Pavanello, D, Orlandi, M, Marchetti, GC., et al. Sensitivity of SARS-CoV-2 Detection With Nasopharyngeal Swabs. Front Public Health. 2021;8:593491.

Alcoba-Florez, J, Gil-Campesino, H, García-Martínez de Artola, D, González-Montelongo, R, Valenzuela-Fernández, A, Ciuffreda, L, Flores, C. Sensitivity of different RT-qPCR solutions for SARS-CoV-2 detection. Int J Infect Dis. 2020;99:190-2.

Finelli L, Gupta V, Petigara T, Yu K, Bauer KA, Puzniak LA. Mortality Among US Patients Hospitalized With SARS-CoV-2 Infection in 2020. JAMA Netw Open. 2021;4(4):e216556.

Watanabe JH, Kwon J, Nan B, Abeles SR, Jia S, Mehta SR. Medication Use Patterns in Hospitalized Patients With COVID-19 in California During the Pandemic. JAMA Netw Open. 2021;4(5):e2110775.

Onder G, Rezza G, Brusaferro S. Case-Fatality Rate and Characteristics of Patients Dying in Relation to COVID-19 in Italy. JAMA. 2020;323(18):1775–6.

Katella, K. Omicron, Delta, Alpha, and More: What To Know About the Coronavirus Variants. Yale Medicine. Available from: https://www.yalemedicine.org/news/covid-19-variants-of-concern-omicron. Last updated Jul 5, 2022; cited Jul 22, 2022.

Kates, J, Tolbert, J, Rouw, A. An Update on Vaccine Roll-Out for 5-11 Year-olds in the U.S. KFF. Available from: https://www.kff.org/coronavirus-covid-19/issue-brief/an-update-on-vaccine-roll-out-for-5-11-year-olds-in-the-u-s/. Last updated Dec 8, 2021; cited Jul 22, 2022.

McKinley, J, Ferré-Sadurní, L. New Allegations of Cover-Up by Cuomo Over Nursing Home Virus Toll. The New York Times. Available from: https://www.nytimes.com/2021/02/12/nyregion/new-york-nursing-homes-cuomo.html. Last updated Mar 25, 2021; cited Sept 2, 2022.




How to Cite

Hardoon, V., Pierce, B. A., Mbanefo, S. C., Shah, H. N., Markan, K., & Forsythe, M. L. (2022). Effects of Social Distancing and Lockdown Protocols on Fatality Rates of COVID-19 in the U.S. during the First Year of the Pandemic. International Journal of Medical Students. https://doi.org/10.5195/ijms.2022.1188



Original Article