Abstract

Introduction

On March 11, 2020, the World Health Organization (WHO) declared a pandemic of COVID-19, the disease caused by the novel coronavirus SARS-CoV-2. The declaration was made when the epidemic, which began in Wuhan, China, was already present in 114 countries/territories/areas, reaching 118,319 cases and 4,292 deaths from the disease ¹1. World Health Organization. Coronavirus disease 2019 (COVID-19). Situation report - 51. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200311-sitrep-51-covid-19.pdf?sfvrsn=1ba62e57_10 (acessado em 11/Jun/2020).
https://www.who.int/docs/default-source/... . Three months later, more than 7 million cases had been reported in the world, with more than 408,000 deaths from COVID-19 in 215 countries/territories/areas around the world ²2. World Health Organization. Coronavirus disease (COVID-19). Situation Report - 142. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200610-covid-19-sitrep-142.pdf?sfvrsn=180898cd_6 (acessado em 11/Jun/2020).
https://www.who.int/docs/default-source/... .

The rapid spread of SARS-CoV-2 in countries and communities due to the virus’ high transmissibility, together with the lack of vaccines and specific and effective antiviral drugs for prevention and treatment of the disease, respectively, makes nonpharmacological interventions the most efficient options for the mitigation and control of COVID-19 at the local and global levels ³3. Cowling BJ, Aiello AE. Public health measures to slow community spread of coronavirus disease 2019. J Infect Dis 2020; 221:1749-51.^,44. Anderson RM, Heesterbeek H, Klinkenberg D, Hollingsworth TD. How will country-based mitigation measures influence the course of the COVID-19 epidemic? Lancet 2020; 395:931-4.. At the population level, such interventions feature social distancing measures, or the efforts aimed at flattening or interrupting the transmission chain by physical distancing between individuals that may be infected and healthy individuals, and to protect those individuals from the risk of developing severe form of disease. The measures include canceling mass events, temporary school and workplace closures, border closures, and recommendation for population self quarantine ⁵5. World Health Organization. Overview of public health and social measures in the context of COVID-19 (Interim guidance). https://www.who.int/publications/i/item/overview-of-public-health-and-social-measures-in-the-context-of-covid-19 (acessado em 11/Jun/2020).
https://www.who.int/publications/i/item/... .

Social distancing measures had been used for the mitigation of previous epidemics and pandemics, including the influenza pandemic of 1918-1919 ⁶6. Markel H, Lipman HB, Navarro JA, Sloan A, Michalsen JR, Stern AM, et al. Nonpharmaceutical interventions implemented by US cities during the 1918-1919 influenza pandemic. JAMA 2007; 298:644-54., the severe acute respiratory syndrome (SARS) epidemic in 2002-2003 ⁷7. Bell DM; World Health Organization Working Group on Prevention of International and Community Transmission of SARS. Public health interventions and SARS spread, 2003. Emerg Infect Dis 2004; 10:1900-6., and the H1N1 influenza pandemic in 2009-2010 ⁸8. Fong MW, Gao H, Wong JY, Xiao J, Shiu EYC, Ryu S, et al. Nonpharmaceutical measures for pandemic influenza in nonhealthcare settings-social distancing measures. Emerg Infect Dis 2020; 26:976-84., and such measures are now widely recommended for the mitigation and control of the COVID-19 pandemic ⁵5. World Health Organization. Overview of public health and social measures in the context of COVID-19 (Interim guidance). https://www.who.int/publications/i/item/overview-of-public-health-and-social-measures-in-the-context-of-covid-19 (acessado em 11/Jun/2020).
https://www.who.int/publications/i/item/... ^,99. European Center for Disease Prevention and Control. Coronavirus disease 2019 (COVID-19) pandemic: increased transmission in the EU/EEA and the UK - seventh update. https://www.ecdc.europa.eu/sites/default/files/documents/RRA-seventh-update-Outbreak-of-coronavirus-disease-COVID-19.pdf (acessado em 11/Jun/2020).
https://www.ecdc.europa.eu/sites/default... ^,1010. Government of Canada. Community-based measures to mitigate the spread of coronavirus disease (COVID-19) in Canada. https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/health-professionals/public-health-measures-mitigate-covid-19.html (acessado em 11/Jun/2020).
https://www.canada.ca/en/public-health/s... ^,1111. Ferguson NM, Laydon D, Nedjati-Gilani G, Imai N, Ainslie K, Baguelin M, et al. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf (acessado em 10/Jun/2020).
https://www.imperial.ac.uk/media/imperia... .

Starting with Wuhan, which began implementation of social distancing measures approximately three weeks after the onset of the epidemic ¹²12. Lau H, Khosrawipour V, Kocbach P, Mikolajczyk A, Schubert J, Bania J, et al. The positive impact of lockdown in Wuhan on containing the COVID-19 outbreak in China. J Travel Med 2020; 2020; 27:taaa037., other Chinese cities, Asian countries, and various countries around the world implemented social distancing measures as community transmission was confirmed successively in these places ¹³13. Cohen J, Kupferschmidt K. Countries test tactics in 'war' against COVID-19. Science 2020; 367:1287-8.. Initial evidence already indicates that this strategy’s adoption in various scenarios has been effective in containing the uncontrolled increase in COVID-19 cases and deaths, especially when associated with isolation of cases and quarantine of contacts of cases ¹¹11. Ferguson NM, Laydon D, Nedjati-Gilani G, Imai N, Ainslie K, Baguelin M, et al. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf (acessado em 10/Jun/2020).
https://www.imperial.ac.uk/media/imperia... ^,1212. Lau H, Khosrawipour V, Kocbach P, Mikolajczyk A, Schubert J, Bania J, et al. The positive impact of lockdown in Wuhan on containing the COVID-19 outbreak in China. J Travel Med 2020; 2020; 27:taaa037.^,1414. Nussbaumer-Streit B, Mayr V, Dobrescu AI, Chapman A, Persad E, Klerings I, et al. Quarantine alone or in combination with other public health measures to control COVID-19: a rapid review. Cochrane Database Syst Rev 2020; 4:CD013574.^,1515. Wu P, Tsang TK, Wong JY, Ng TWY, Ho F, Gao H, et al. Suppressing COVID-19 transmission in Hong Kong: an observational study of the first four months. Research Square 2020; 9 jun. https://www.researchsquare.com/article/rs-34047/v1.
https://www.researchsquare.com/article/r... ^,1616. Figueiredo AM, Codina AD, Figueiredo DCMM, Saez M, León AC. Impact of lockdown on COVID-19 incidence and mortality in China: an interrupted time series study. Bull World Health Organ 2020; 6 abr. http://dx.doi.org/10.2471/BLT.20.256701.
http://dx.doi.org/10.2471/BLT.20.256701... ^,1717. Oliveira C. Does "staying at home" save lives? An estimation of the impacts of social isolation in the registered cases and deaths by Covid-19 in Brazil. SSRN 2020; 13 mai. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3593947.
https://papers.ssrn.com/sol3/papers.cfm?... . However, there is still uncertainty on the effectiveness of different types of measures when considered singly or combined, or the effect of the timing of these measures on the epidemiological progression of the disease.

Beyond the health sector, it is important to address the inevitable social and economic impacts of social distancing measures ¹⁸18. Nicola M, Alsafi Z, Sohrabi C, Kerwan A, Al-Jabir A, Iosifidis C, et al. The socio-economic implications of the coronavirus and COVID-19 pandemic: a review. Int J Surg 2020; 78:185-93.. It is thus important to have a careful evaluation of the most appropriate epidemiological timing for the measures’ implementation and duration, aimed at maximizing the intended health effects and minimizing the social and economic harms ³3. Cowling BJ, Aiello AE. Public health measures to slow community spread of coronavirus disease 2019. J Infect Dis 2020; 221:1749-51..

The first case of COVID-19 in Brazil was confirmed on February 26, 2020, in the city of São Paulo ¹⁹19. Ministério da Saúde. Boletim Epidemiológico Especial - 14. COE-COVID19. https://portalarquivos.saude.gov.br/images/pdf/2020/April/27/2020-04-27-18-05h-BEE14-Boletim-do-COE.pdf (acessado em 11/Mai/2020).
https://portalarquivos.saude.gov.br/imag... . A month after this first confirmed case, every state of Brazil had already reported cases of the disease, with deaths recorded in eight states ²⁰20. Ministério da Saúde. Brasil registra 2.915 casos confirmados de coronavírus e 77 mortes. https://www.saude.gov.br/noticias/agencia-saude/46610-brasil-registra-2-915-casos-confirmados-de-coronavirus-e-77-mortes (acessado em 11/Mai/2020).
https://www.saude.gov.br/noticias/agenci... . However, the trend in the number of cases and deaths differs between states ²¹21. Ministério da Saúde. Painel Coronavírus. https://covid.saude.gov.br/ (acessado em 11/Mai/2020).
https://covid.saude.gov.br/... , possibly due to sociodemographic and geographic differences, the timing of the infection’s introduction, and states’ and municipalities’ autonomy to determine which measures to adopt to mitigate COVID-19 and the measures’ timing, according to their respective scenarios ²²22. Supremo Tribunal Federal. STF reconhece competência concorrente de estados, DF, municípios e União no combate à Covid-19. http://www.stf.jus.br/portal/cms/verNoticiaDetalhe.asp?idConteudo=441447 (acessado em 11/Jun/2020).
http://www.stf.jus.br/portal/cms/verNoti... . It is thus necessary to map the measures implemented in the various states in order to raise hypotheses and assess the most appropriate timing for the implementation and the results of different measures in different states and regions of Brazil. To answer these questions, it is essential to have a complete database obtained through a systematic search process that records the types of measures adopted in each state, along with the timing of their implementation.

This study thus aimed to describe the social distancing measures implemented by the Brazilian states, including the types of measures and the chronological and epidemiological timing of their implementation, considering the number of COVID-19 cases and deaths in each location.

Methods

Study design, location, and period

This is a descriptive study with data from each of the 27 Brazilian states between the date of the first confirmed COVID-19 case in Brazil, February 26, 2020, and June 30, 2020.

Data source and collection

Social distancing measures

A survey of the legislations on social distancing measures was conducted for each of the Brazilian states. The search was done on each state government’s official website and Government Register (Diário Oficial). We reviewed the decrees, laws, rulings, technical notes, and decisions by the COVID-19 Emergency Committee (the latter in the State of Minas Gerais), all published during the study period.

The following information was extracted from the surveyed legislations and registered in a structured spreadsheet for this purpose: date of publication and description of the provision, type of measure implemented, and date of implementation. The data were collected from March 10 to July 1, 2020, by a team of three researchers.

Epidemiological data

The number of COVID-19 confirmed cases and deaths that occurred during the study period notified by each state epidemiological surveillance system followed national and state standardization procedures ²³23. Ministério da Saúde. Boletim Epidemiológico - 04. https://www.saude.gov.br/images/pdf/2020/marco/04/2020-03-02-Boletim-Epidemiol--gico-04-corrigido.pdf (acessado em 11/Mai/2020).
https://www.saude.gov.br/images/pdf/2020... , and were obtained from the Brasil.io platform (https://brasil.io/covid19/), which collects and reviews the data daily, keeping them more accurate and up-to-date. The source for this site is the official data reported by the epidemiological bulletins and reports of the 27 State Health Departments ²⁴24. Brasil.IO. Metodologia de coleta dos dados. https://docs.google.com/document/d/1escumcbjS8inzAKvuXOQocMcQ8ZCqbyHU5X5hFrPpn4/edit# (acessado em 13/Mai/2020).
https://docs.google.com/document/d/1escu... .

Categories of social distancing measures

The social distancing measures were grouped in 10 categories, which were later regrouped in six categories for this analysis, as described in Box 1.

Timing of the implementation of social distancing measures

The timing of the implementation of each social distancing measure considered both the chronological and epidemiological timing of its implementation. Generally, the chronological date was defined according to the following criteria: (a) date on which the legislation or measure entered into force or the date on which the legislation indicated that the measure should begin, and not the date on which the legislation was signed; (b) when the measure was implemented progressively per location, for example, beginning in the state capital and from there to the metropolitan area and finally the entire state, we considered the date by which the measure had been implemented in the entire state; and (c) for all the categories except economic lockdown, we only considered the date when the measure had been implemented in the entire state (and not when it had been implemented in only one or two municipalities).

For the category economic lockdown, we considered full economic lockdown when all five distancing measures were implemented, namely: (1) suspension of nonessential in-person public services and/or orientation from public employees via telework; (2) closing of business centers, gyms, and private sports centers; (3) suspension of functioning of food establishments, including ban on in-person service and/or on-site food consumption; (4) suspension of public service by service providers and other nonessential commercial establishments; and (5) suspension of nonessential industrial activities. When not all five measures were implemented, or when any of the measures was only partially implemented (for example, food or commercial establishments with restrictions on occupancy or closed only under some circumstances), when the measures were only implemented in the state capitals or in a group of municipalities but not in the entire state, or when the legislation recommended but did not enforce the suspensions, the economic lockdown was considered partial.

For the suspension of events, we considered the date of the suspension of events of any kind, regardless of audience size, whether or not they required public permits, and the suspension of cultural, leisure-time, religious, and sports events. We did not consider specific decrees related to events conducted by the state government on prior dates. For school closure, we considered the data of suspension of classroom activities in public schools. For quarantine of risk groups, we considered the date on which public employees belonging to risk groups were quarantined, namely: individuals over 60 years, pregnant women, and/or individuals with chronic noncommunicable diseases were instructed to work outside the physical installations of their respective agency, via telework. For the category restrictions on transportation, we considered the first date on which the suspension/ban was issued on collective transportation of intermunicipal and/or interstate passengers, in any modality (except air travel), public and/or private. We also considered cases in which the suspension or ban on transportation only applied to individuals from states and states and/or municipalities with COVID-19 cases that declared emergency situations. Finally, we defined the population quarantine as the date on which it was recommended for the population (from that moment on) to limit circulation to strictly necessary activities and/or increase the time sheltering at home.

The epidemiological timing of each measure’s implementation was categorized arbitrarily as: (a) early, when it occurred before the first COVID-19 case was reported; (b) intermediate I, when it occurred between the first and tenth case; (c) intermediate II, when it occurred between the 11^th and 50^th case; and (d) late, when it occurred after the 50^th case. This timing was also presented according to the number of days before or after the date of implementation of each category of measures based on the first confirmed death of the disease.

Data synthesis and analysis

For each state, we identified that chronological dates of implementation of each social distancing measure and calculated the difference in days between the first measure’s date of implementation and the economic lockdown (full or partial).

The epidemiological timing of the measures’ implementation in each state was categorized as early, intermediate I, intermediate II, and late. For the category economic lockdown, the timing was presented graphically, based on the first reported case of the disease in each location, on a log scale, grouped by states that had implemented full or partial lockdowns. The epidemiological timing of each category’s implementation was also presented according to the number of days before or after the first reported COVID-19 death by state.

For data visualization, a public-access graphic interface (https://medidas-covidbr-iptsp.shinyapps.io/painel/) was elaborated that presents the trend in confirmed COVID-19 cases and deaths over time and the social distancing measures adopted in each state in response to the COVID-19 pandemic.

Since these were open-access secondary data, no approval was necessary from the Institutional Review Board.

Results

Four or more categories of social distancing measures were implemented in all the Brazilian states. Suspension of events and/or quarantine of risk groups were the first measures to be implemented, except in the state of Tocantins, which implemented suspension of school classes first. Mato Grosso do Sul, Tocantins, Espírito Santo, São Paulo, Federal District, and Rio Grande do Norte did not restrict intermunicipal and/or interstate passenger transportation, and 20 states did not implement a quarantine of the entire population (Table 1).

The first social distancing measures implemented in Brazil were in the Federal District, on March 11, 2020. In the other states, most of the measures were implemented in the second half of March, from March 13 to 28, 2020. Table 1 shows the time in days between implementation of the first measure and the full or partial economic lockdown in each state. Mato Grosso do Sul, Santa Catarina, and Rio Grande do Sul were the states that adopted these groups of measures in the shortest time, with a difference of one or two days. At the other extreme, in Pará, the time between implementation of the first measure and the economic lockdown was 50 days. In 74% of the states, the time between implementation of the first measure and the full or partial economic lockdown was one week or less.

The epidemiological timing of the social distancing categories varied little between Brazilian states, since most states implemented all the categories except the population quarantine between the first and tenth case of COVID-19. For suspension of events, suspension of classes, and quarantine of risk groups, some states, mainly in the North and Northeast of Brazil, implemented this set of measures before the first COVID-19 case was reported. Paraíba, Espírito Santo, and Maranhão were the only states that adopted some category of measures after the 50th case of COVID-19 (restrictions on transportation in Paraíba and population quarantine in Espírito Santo and Maranhão) (Table 2).

All seven states that implemented full economic lockdowns did so within 13 days after reporting the first COVID-19 case. Amapá and Maranhão implemented this category when they had one and two cases of COVID-19, respectively, and Ceará did so when it had 68 cases. Among the states that implemented partial lockdowns in the Central, South, and Southeast regions, the state of Mato Grosso announced the measure when six confirmed cases of the disease had been reported, while São Paulo already had 810 cases. In the North and Northeast regions, Roraima and Paraíba had one case each, Bahia had 127 cases, and Pará had 4,756 reported COVID-19 cases when the measure was implemented (Figure 1).

Table 3 shows the number of days before or after the first reported COVID-19 death in each state in relation to the date of implementation of the various social distancing measures. Most of the states implemented the measures before the first death, and Tocantins implemented the measures 30 days before the state’s first reported death. In relation to partial economic lockdown, Pará, Rio Grande do Norte, and São Paulo were the only states that implemented this group of measures after the first death, with intervals of 34, 5, and 7 days, respectively.

Discussion

The Brazilian Supreme Court assigned to the states, Federal District, and municipalities the authority to decide on the implementation of social distancing measures to mitigate and suppress COVID-19 ²²22. Supremo Tribunal Federal. STF reconhece competência concorrente de estados, DF, municípios e União no combate à Covid-19. http://www.stf.jus.br/portal/cms/verNoticiaDetalhe.asp?idConteudo=441447 (acessado em 11/Jun/2020).
http://www.stf.jus.br/portal/cms/verNoti... . Thus, few Federal measures were implemented, and they were limited to restrictions on the entry of foreigners into Brazil ²⁵25. Brasil. Portal da Legislação: Legislação COVID-19. http://www4.planalto.gov.br/legislacao/portal-legis/legislacao-covid-19 (acessado em 11/Jun/2020).
http://www4.planalto.gov.br/legislacao/p... and the ruling that persons over 60 years of age should practice social distancing, limiting their movements to strictly necessary activities ²⁶26. Ministério da Saúde. Portaria nº 454 de 20 de março de 2020. Declara, em todo o território nacional, o estado de transmissão comunitária do coronavírus (covid-19). Diário Oficial da União 2020; 20 mar.. In addition to these measures, the Brazilian Ministry of Health announced an action plan on March 14, 2020, recommending that the municipal, state, and Federal District health departments assess and adopt nonpharmacological measures to control COVID-19, according to the local epidemiology of disease transmission ²⁷27. Ministério da Saúde. Boletim Epidemiológico nº 06 do Centro de Operações de Emergências em Saúde Pública (COE COVID-19). https://www.saude.gov.br/images/pdf/2020/marco/24/03--ERRATA---Boletim-Epidemiologico-05.pdf (acessado em 11/Jun/2020).
https://www.saude.gov.br/images/pdf/2020... .

As in other countries, the Brazilian states implemented not only a single measure, but a set of social distancing measures for which the evidence showed greater effectiveness for the mitigation and suppression of COVID-19, especially when associated with isolation of cases and contact quarantine ¹¹11. Ferguson NM, Laydon D, Nedjati-Gilani G, Imai N, Ainslie K, Baguelin M, et al. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf (acessado em 10/Jun/2020).
https://www.imperial.ac.uk/media/imperia... ^,2828. Cowling BJ, Ali ST, Ng TWY, Tsang TK, Li JCM, Fong MW, et al. Impact assessment of non-pharmaceutical interventions against coronavirus disease 2019 and influenza in Hong Kong: an observational study. Lancet Public Health 2020; 5:e279-88.^,2929. Summan A, Nandi A. Timing of non-pharmaceutical interventions to mitigate COVID-19 transmission and their effects on mobility: a cross-country analysis. medRxiv 2020; 13 mai. https://www.medrxiv.org/content/10.1101/2020.05.09.20096420v1.
https://www.medrxiv.org/content/10.1101/... . Another important finding is that the progressive implementation of various types of measures occurred in a short time interval, mostly culminating in the full or partial lockdown of nonessential economic activities, following the same sequence as normally used in other countries that adopted these measures to fight COVID-19 ³⁰30. Hale T, Webster S, Petherick A, Phillips T, Kira B. Oxford COVID-19 Government Response Tracker, Blavatnik School of Government; 2020. https://www.bsg.ox.ac.uk/research/research-projects/coronavirus-government-response-tracker (acessado em 15/Jun/2020).
https://www.bsg.ox.ac.uk/research/resear... .

Among the states and Federal District, the latter was the first to implement a series of social distancing measures, on exactly the same day as the WHO declared COVID-19 a pandemic ¹1. World Health Organization. Coronavirus disease 2019 (COVID-19). Situation report - 51. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200311-sitrep-51-covid-19.pdf?sfvrsn=1ba62e57_10 (acessado em 11/Jun/2020).
https://www.who.int/docs/default-source/... . From that date on, all Brazilian states launched measures that were mostly concentrated in the second half of March, less than a month since the first confirmed COVID-19 case in the country ¹⁹19. Ministério da Saúde. Boletim Epidemiológico Especial - 14. COE-COVID19. https://portalarquivos.saude.gov.br/images/pdf/2020/April/27/2020-04-27-18-05h-BEE14-Boletim-do-COE.pdf (acessado em 11/Mai/2020).
https://portalarquivos.saude.gov.br/imag... . These findings corroborate those of the University of Oxford research group (The Oxford COVID-19 Government Response Tracker - OxCGRT), which conducted a survey and monitoring of social distancing measures in more than 160 countries and found that the governments’ responses to COVID-19 have generally grown stronger over the course of the epidemic, with a major increase in the month of March, notwithstanding variations between countries ³¹31. Hale T, Webster S, Petherick A, Phillips T, Kira B. Variation in government responses to COVID-19 (version 6.0). Blavatnik School of Government working paper. https://www.bsg.ox.ac.uk/sites/default/files/2020-05/BSG-WP-2020-032-v6.0.pdf (acessado em 15/Jun/2020).
https://www.bsg.ox.ac.uk/sites/default/f... .

In most Brazilian states, most of the social distancing measures were implemented before the tenth reported case and the first death from the disease, which was early when compared to the findings by Summan & Nandi ²⁹29. Summan A, Nandi A. Timing of non-pharmaceutical interventions to mitigate COVID-19 transmission and their effects on mobility: a cross-country analysis. medRxiv 2020; 13 mai. https://www.medrxiv.org/content/10.1101/2020.05.09.20096420v1.
https://www.medrxiv.org/content/10.1101/... , who assessed the timing of social distancing measures in various countries and found that the school closure occurred on average 13 days after the first reported case, followed by restrictions on international air travel (average of 18 days) and national lockdowns, on average 21 days after the first case. Summan and Nandi also found that poorer countries, those with more reported cases two weeks after the first case, less democratic systems, and those with smaller, less dense, and younger populations implemented these measures earlier, while wealthier countries with larger populations and that were better prepared in terms of the health system’s response implemented the measures later in relation to the occurrence of local COVID-19 cases.

Evidence suggests that early adoption of social distancing measures is fundamental for slowing the disease transmission and thus flattening the curve of cases and reducing the demand on health services ³3. Cowling BJ, Aiello AE. Public health measures to slow community spread of coronavirus disease 2019. J Infect Dis 2020; 221:1749-51.^,1414. Nussbaumer-Streit B, Mayr V, Dobrescu AI, Chapman A, Persad E, Klerings I, et al. Quarantine alone or in combination with other public health measures to control COVID-19: a rapid review. Cochrane Database Syst Rev 2020; 4:CD013574.^,3232. European Centre for Disease Prevention and Control. Considerations relating to social distancing measures in response to the COVID-19 epidemic. https://www.ecdc.europa.eu/en/publications-data/considerations-relating-social-distancing-measures-response-covid-19-second (acessado em 15/Jun/2020).
https://www.ecdc.europa.eu/en/publicatio... ^,3333. World Health Organization. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19) https://www.who.int/docs/default-source/coronaviruse/who-china-joint-mission-on-covid-19-final-report.pdf?sfvrsn=fce87f4e_2 (acessado em 15/Jun/2020).
https://www.who.int/docs/default-source/... ^,3434. Courtemanche C, Garuccio J, Le A, Pinkston J, Yelowitz A. Strong social distancing measures in the United States reduced the COVID-19 growth rate. Health Aff (Millwood) 2020; 39:1237-46.. A study that simulated the COVID-19 epidemic in cities in Continental China estimated that if a series of nonpharmacological interventions, including social distancing, had been implemented one week, two weeks, or three weeks before the epidemic’s onset in China, the number of COVID-19 cases could have been reduced by 66%, 86%, and 95%, respectively, besides significantly reducing the number of affected areas ³⁵35. Lai S, Ruktanonchai NW, Zhou L, Prosper O, Luo W, Floyd JR, et al. Effect of non-pharmaceutical interventions for containing the COVID-19 outbreak: an observational and modelling study. medRxiv 2020; 13 mai. https://www.medrxiv.org/content/10.1101/2020.03.03.20029843v3.. In the United States, a study in March-April 2020 concluded that the adoption of social distancing measures enforced by the Federal government reduced the daily growth rate by 5.4 percentage points after 1 to 5 days, 6.8 points after 6 to 10 days, 8.2 points after 11 to 15 days, and 9.1 points after 16 to 20 days ³⁴34. Courtemanche C, Garuccio J, Le A, Pinkston J, Yelowitz A. Strong social distancing measures in the United States reduced the COVID-19 growth rate. Health Aff (Millwood) 2020; 39:1237-46..

In Brazil, a time series study of COVID-19 deaths in the state of São Paulo showed that social distancing strategies implemented from March 16 to 22, 2020, resulted in a substantial reduction in the number of infections, with the most evident reduction in the city of São Paulo from April 5 to 20. The author explains that the time between the measures’ implementation and the reduction in the number of deaths was about 17 days, equivalent to the onset of symptoms and death from COVID-19 ³⁶36. Cruz CHB. Social distancing in São Paulo State: demonstrating the reduction in cases using time series analysis of deaths due to COVID-19. Rev Bras Epidemiol 2020; 23:e200056.. These findings corroborate those reported in another study that assessed the impact of nonpharmacological interventions in the cities of São Paulo and Rio de Janeiro, using mobility-oriented transmission models, and found that the reproduction rate (Rt) for SARS-CoV-2 over time in these cities dropped below 1 soon after the implementation of nonpharmacological interventions, but increased to between 1 and 1.3 after the measures were relaxed there ³⁷37. Candido DS, Claro IM, Jesus JG, Souza WM, Moreira FRR, Dellicour S, et al. Evolution and epidemic spread of SARS-CoV-2 in Brazil. MedRxiv 2020; 23 jun. https://www.medrxiv.org/content/10.1101/2020.06.11.20128249v2.
https://www.medrxiv.org/content/10.1101/... .

Together with the timing of implementation, the measures’ stringency and duration appear to be essential for the intervention’s success ¹¹11. Ferguson NM, Laydon D, Nedjati-Gilani G, Imai N, Ainslie K, Baguelin M, et al. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf (acessado em 10/Jun/2020).
https://www.imperial.ac.uk/media/imperia... . The OxCGRT found that by May 30, 2020, most of the 160 countries monitored by the group presented a stringency index for the distancing measures greater than 70 (on a scale of 0-100, where 100 is the most stringent), with Brazil showing an index of 81.02 ³⁰30. Hale T, Webster S, Petherick A, Phillips T, Kira B. Oxford COVID-19 Government Response Tracker, Blavatnik School of Government; 2020. https://www.bsg.ox.ac.uk/research/research-projects/coronavirus-government-response-tracker (acessado em 15/Jun/2020).
https://www.bsg.ox.ac.uk/research/resear... . This index is also being monitored in Brazil’s states and state capitals by the Institute for Applied Economic Research (IPEA) ³⁸38. Moraes RF. Índice de medidas legais de distanciamento social. http://tinyurl.com/ipeacoronavirus (acessado em 15/Jun/2020).
http://tinyurl.com/ipeacoronavirus... , which found that the measures’ degree of stringency in Brazilian states and state capitals increased continuously up to March 23-24, 2020, although some states adopted substantially more rigorous policies than others ³⁹39. Moraes RF. Medidas legais de incentivo ao distanciamento social: comparação das políticas de governos estaduais e prefeituras das capitais no Brasil. Nota técnica 16. https://www.ipea.gov.br/portal/index.php?option=com_content&view=article&id=35462&Itemid=4 (acessado em 15/Jun/2020).
https://www.ipea.gov.br/portal/index.php... , and that the measures’ stringency has decreased since early June, with persistent variations between the different states and state capitals ⁴⁰40. Moraes RF. COVID-19 e medidas legais de distanciamento social: isolamento social, gravidade da epidemia e análise do período de 25 de maio a 7 de junho de 2020 (boletim 5). Nota técnica 22. https://www.ipea.gov.br/portal/images/stories/PDFs/nota_tecnica/200610_nt_dinte_n_22.pdf (acessado em 15/Jun/2020).
https://www.ipea.gov.br/portal/images/st... .

The duration should be long enough to achieve the desired epidemiological effects, causing a minimum of social and economic harms ³3. Cowling BJ, Aiello AE. Public health measures to slow community spread of coronavirus disease 2019. J Infect Dis 2020; 221:1749-51. and avoiding the attrition and loss of adherence by the population, as has already been observed in many Brazilian states ⁴⁰40. Moraes RF. COVID-19 e medidas legais de distanciamento social: isolamento social, gravidade da epidemia e análise do período de 25 de maio a 7 de junho de 2020 (boletim 5). Nota técnica 22. https://www.ipea.gov.br/portal/images/stories/PDFs/nota_tecnica/200610_nt_dinte_n_22.pdf (acessado em 15/Jun/2020).
https://www.ipea.gov.br/portal/images/st... . From the socioeconomic point of view, a review study has already shown that social distancing, self-isolation, and travel restrictions have resulted in unemployment in many economic sectors, work overload in others, and an increase in cases of domestic violence (physical, emotional, and sexual) ¹⁸18. Nicola M, Alsafi Z, Sohrabi C, Kerwan A, Al-Jabir A, Iosifidis C, et al. The socio-economic implications of the coronavirus and COVID-19 pandemic: a review. Int J Surg 2020; 78:185-93.. Another study also found that the COVID-19 pandemic is causing additional health problems such as stress, anxiety, depressive symptoms, insomnia, and other mental disorders, even while acknowledging that studies related to COVID-19 and mental health are still scarce ⁴¹41. Torales J, O'Higgins M, Castaldelli-Maia JM, Ventriglio A. The outbreak of COVID-19 coronavirus and its impact on global mental health. Int J Soc Psychiatry 2020; 66:317-20.. These findings have led some researchers to prefer the term “physical distancing” rather than “social distancing” to emphasize the need for us to remain socially connected, while maintaining physical distancing.

Furthermore, the overly early implementation of social distancing measures may result in their early relaxation at times when epidemiological evidence shows an increase in cases and deaths. The way (and the extent to which) early implementation of social distancing measures impacted the epidemic’s progression, and also the possible premature flexibilizations in various states, is something that should be assessed in specific studies for this purpose.

The international literature has proposed the implementation of intermittent strategies with variable periodicities, including restrictions and flexibilizations over time, based on epidemiological indicators. This approach is being considered for the immediate future, until a safe and effective vaccine is available, based on the belief that due to the large number of susceptible individuals, a second wave of SARS-CoV-2 infections is likely ⁴²42. Kissler SM, Tedijanto C, Goldstein E, Grad YH, Lipsitch M. Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period. Science 2020; 368:860-8..

This study has limitations that should be addressed. Since this is a descriptive study, it does not have the potential to verify the effect of distancing measures on the evolution of COVID-19 cases and deaths, but it raises hypotheses that may be validated in subsequent studies. Besides, the survey was conducted in state-level legislation, not at the municipal level, and according to the Supreme Court ruling on April 15, 2020, the municipalities have the autonomy to issue different recommendations from those of the respective state ²²22. Supremo Tribunal Federal. STF reconhece competência concorrente de estados, DF, municípios e União no combate à Covid-19. http://www.stf.jus.br/portal/cms/verNoticiaDetalhe.asp?idConteudo=441447 (acessado em 11/Jun/2020).
http://www.stf.jus.br/portal/cms/verNoti... . Another limitation is that we identified the distancing measures issued or recommended by the state legislation, while the actual adherence to these measures cannot be assessed with this study’s design.

In conclusion, the current study found that all Brazilian states implemented comprehensive and early social distancing measures in a short space of time, aimed at mitigating the impact of COVID-19. However, the impact of this early implementation on the epidemiological evolution of the disease and possible early flexibilization of these measures with inadequate epidemiological timing is still not clear. This emphasizes the need for constant monitoring, focused on the trends in COVID-19 cases in the states that are already relaxing the measures, in order for the efforts achieved in the mitigation of the disease not to be lost with flexibilization. This also emphasizes the need for administrators to back their decisions on evidence when implementing, relaxing, or reintroducing social distancing measures in each state, as well as society’s collaboration in fighting this disease, following the recommendations at the individual, environmental, and community levels.

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