Accessibility / Report Error

Strengthening the surveillance and information activities is urgent and essential to reduce the transmission force of SARS-CoV-2* * Presented to the Scientific Committee of the Northeast Consortium of Governors.

COVID-19 is caused by the SARS-CoV-2 virus, an agent that is rapidly transmitted by the respiratory route and eventually by contaminated surfaces. After nearly 18 months of the pandemic and its effects, a sustained reduction in the incidence of cases, severe cases, and deaths is expected due to the increase in vaccination coverage. However, given the slow pace of vaccination actions11. Brasil. Ministério da Saúde. Vacinação contra a Covid-19 no Brasil. [acessado em 24 jul. 2021]. Disponível em: Disponível em:
, it is a time for caution, making it necessary to implement new actions capable of reducing and maintaining the transmission threshold of SARS-CoV-2 at low levels. It must be noted that while vaccines are the most important resources in the control of the pandemic, with high efficacy in reducing severe cases and deaths, they have lesser effects on the transmission of the virus22. Geddes L. How effective are COVID-19 vaccines in the real-world? GAVI, The Vaccine Alliance. [acessado em 24 jul. 2021]. Disponível em: Disponível em:
. Therefore, until high levels of vaccination coverage are reached, it is extremely important that non-pharmacological measures are maintained, in particular the mandatory use of masks, social distancing, and control of the flow of intra- and inter-urban commuting33. Aquino EML, Silveira IH, Pescarini JM, Aquino R, Souza-Filho JA, Rocha AS, et al. Social distancing measures to control the COVID-19 pandemic: potential impacts and challenges in Brazil. Cien Saude Colet 2020; 25 (Suppl 1): 2423-46.
,44. Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, van der Westhuizen HM, et al. An evidence review of face masks against COVID-19. Proc Natl Acad Sci U S A 2021; 118 (4): e2014564118.
,55. Houvèssou GM, Souza TP, Silveira MF. Lockdown-type containment measures for COVID-19 prevention and control: a descriptive ecological study with data from South Africa, Germany, Brazil, Spain, United States, Italy and New Zealand, February - August 2020. Epidemiol Serv Saude 2021; 30 (1): e2020513.

There is also a pressing need for measures that ensure continuous transmission control efforts by tracking cases and contacts in each community, so that health professionals can guide and adopt appropriate measures for each situation (isolation, quarantine, use of masks, etc.). Such measures aim to minimize the transmission potential of the virus, as they contribute not only to a reduction in the number of cases66. Teixeira MG, Medina MG, Costa MCN, Barral-Netto M, Carreiro R, Aquino R. Reorganization of primary health care for universal surveillance and containment of COVID-19. Epidemiol Serv Saude 2020; 29 (4): e2020494.
,77. Sales CMM, Silva AI, Maciel ELN. COVID-19 health surveillance in Brazil: investigation of contacts by primary health care as a community protection strategy. Epidemiol Serv Saude 2020; 29 (4): 2020373.
,88. Chung SC, Marlow S, Tobias N, Alogna A, Alogna I, You SL, et al. Lessons from countries implementing find, test, trace, isolation and support policies in the rapid response of the COVID-19 pandemic: a systematic review. BMJ Open. 2021; 11 (7): e047832.
,99. Bilinski A, Mostashari F, Salomon JA. Modeling Contact tracing strategies for COVID-19 in the context of relaxed physical distancing measures. JAMA Netw Open 2020; 3 (8): e2019217.
, as well as to contain the emergence or introduction of new variants1010. Rochman ND, Wolf YI, Faure G, Mutz P, Zhang F, Koonin EV. Ongoing global and regional adaptive evolution of SARS-CoV-2. Proc Natl Acad Sci U S A 2021;118 (29): e2104241118.
, possibly more transmissible or pathogenic, such as the Delta variant, recently introduced - though already actively circulating - in Brazil1111. Platonow V. Ministro da Saúde diz que variante Delta está sendo monitorada. Agência Brasil; 2021[acessado em 24 jul. 2021]. Disponível em: Disponível em:

Although the Brazilian Epidemiological Surveillance System of the Unified Health System (Sistema Único de Saúde - SUS) is considered one of the best national surveillance systems when compared to similar countries in terms of development and size of the population, the COVID-19 pandemic has exposed its weaknesses, resulting from accentuated disinvestment in recent years. It should be emphasized that, in addition to the lack of national coordination of epidemic control efforts, a large part of the resources added to SUS dealing with this Public Health Emergency have been directed toward expanding medium- and high-complexity hospital care. These initiatives were of paramount importance to respond to the increased demand generated by severe cases. However, in parallel, there should have been the implementation of control efforts in the primary care network to reduce the transmission of SARS-CoV-2, which only happened in a very timid way and, more often, in municipalities that, on their own, took this initiative. That is, the surveillance of new infections, new cases, and their contacts has been weak, although these actions, by interrupting transmission, prevent new infections, leading to a reduction in hospital demand and the number of deaths. Epidemiological surveillance (ES) measures have a broad spectrum of action, ranging from promoting hygiene measures to active case and contact finding and notification, tracking contacts to guide and monitor the isolation of the infected, and quarantine, when indicated. Examples of success are the municipalities of Araraquara (SP)1212. Figueiredo Filho DB, Silva LEO. Social distancing and severe acute respiratory syndrome coronavirus 2 transmission: A case study from Araraquara, São Paulo, Brazil. Rev Soc Bras Med Trop 2021; 54: e01972021.
and Eusébio (CE)1313. Prefeitura Municipal de Eusébio. Eusébio já realizou testes de Covid-19 em 26,5% da sua população. 2021 [acessado em 30 jul. 2021]. Disponível em:
,1414. Paulino N. Eusébio tem a maior proporção de população testada para Covid-19 no Ceará. Diário do Nordeste; 2021 [acessado em 30 jul. 2021]. Disponível em: Disponível em:
, which managed to implement vigorous ES programs, with marked reductions in their infection rates.

Our proposal here aims to sensitize policymakers and implementors to the need to implement effective efforts to reduce the transmission of SARS-CoV-2 through the strengthening and expansion of effective ES strategies at the community level. This requires identifying cases of COVID 19 - whether isolated or in clusters - and, with the support of a fast information network, adopting the necessary containment measures to reduce and maintain transmission at low levels.

Since a previously unknown agent caused COVID-19, there were technical difficulties for the rapid diagnosis of cases (symptomatic or asymptomatic) both in health units and in communities. The only diagnostic procedure initially available requires collecting samples with a nasopharyngeal swab for RT-PCR, which must be sent to a specialized laboratory. Due to the overload of samples for analysis, it can take several days to issue and return the results. Thus, there is substantial delay in the flow of information to health units about cases in their respective coverage areas, in addition to insufficient detection of cases. These problems, associated with the lack of incentives for measures to reduce community transmission, have made the efforts to contain the transmission of ­SARS-CoV-2 through case identification and contact tracking either non-existent or ineffective in many municipalities. Although some Governors and Mayors have adopted collective efforts to contain transmission through the implementation of non-pharmacological measures, such as social distancing, commuting restrictions, and use of masks, the decisions to adopt them have been, in general, based on hospital indicators, especially the rate of occupation of intensive care units (ICU), but not in epidemiological indicators related to the intensity of SARS-CoV-2 transmission.

Given this scenario, we propose that policymakers adopt mandatory active case search, contact tracking, and prompt control efforts at the local level. Such actions must be developed by primary health care personnel in conjunction with epidemiologists in each municipality66. Teixeira MG, Medina MG, Costa MCN, Barral-Netto M, Carreiro R, Aquino R. Reorganization of primary health care for universal surveillance and containment of COVID-19. Epidemiol Serv Saude 2020; 29 (4): e2020494.
,77. Sales CMM, Silva AI, Maciel ELN. COVID-19 health surveillance in Brazil: investigation of contacts by primary health care as a community protection strategy. Epidemiol Serv Saude 2020; 29 (4): 2020373.
. It is noteworthy that many public schools are located in the areas covered by primary health care units, favoring interventions to protect education workers, students, and their families. In turn, for interventions to be adopted universally, it will be necessary to allocate resources for the local level, mainly to train and expand work teams to implement these activities following the daily monitored epidemiological situation. It is important to emphasize that there has been an advance in diagnostic tools and that rapid testing of virus antigens is available, enabling the rapid detection of cases in communities. These new technologies are already in use and should be accessible to teams actively tracking cases and their contacts. Speed in diagnosis is one of the main factors that enable early identification of cases, contact tracking, and better control of the SARS-CoV-2 spread.


In order to achieve these goals, we propose that guidelines for strengthening epidemiological surveillance for COVID-19 at the local level be quickly developed, as to reduce community transmission of SARS-CoV-2.

In addition to other guidelines and activities, these guidelines should include:

  1. Identification of cases in their initial phase, using systematic, consistent, and continuous monitoring (antigen testing in symptomatic individuals; active search for cases and contacts; adoption of other control measures, etc.). Each local health system must adapt the standard(s) according to its territorial specificity, social and economic reality and family health coverage, among other aspects;

  2. Contact tracking to identify individuals who have been exposed to infection through close contact with a case, whether symptomatic or asymptomatic. It requires rapid antigen testing of all contacts to detect potential symptomatic or asymptomatic transmitters regardless of symptoms;

  3. Adopting measures to contain transmission by isolating positive cases and quarantining negative ones and monitoring these people. In addition to health system requirements, this requires guidance for individuals and families and as well as in loco of the possibility of home isolation;

  4. Ensuring institutional support and social protection measures for cases and contacts who have difficulties in complying with isolation and/or quarantine. If necessary, provide alternatives for home isolation (school, shelter, neighbourhood association, sports court, among other social facilities) or family rearrangements. Professionals from the Primary Care Units must monitor these situations;

  5. Adoption of collective containment measures when there is evidence of increased transmission in an area, seeking to verify the radius of influence of these possible clusters of cases (clusters) to expand the control action to contiguous geographic areas;

  6. Immediate sharing of laboratory test results of COVID-19 produced by Central Laboratories of the States/LACENs and other public or private laboratories that perform PCR and/or Antigen Tests, for immediate adoption of the appropriate measures mentioned above;

  7. Establishing or strengthening the flow of information on cases diagnosed in Emerghency Care Units/UPAs, clinics, and public and private hospitals to immediately trigger the indicated containment actions;

  8. Guaranteeing access and use of personal protective equipment and other hygiene measures to prevent infections among the health professionals involved in these activities following current regulations;

  9. Encouraging the widespread use of efficient face masks and providing them to vulnerable populations.

  10. Increasing ES in workplaces so that containment efforts are taken there on time;

  11. Increasing ES in schools and using rapid communication channels links these efforts to the Primary Health Care system to rapidly and effectively control outbreaks in the school community. It must involve school and health workers, social assistance staff, students, and their families;

  12. Ensuring broad vaccination, with an active search for the unvaccinated and those missing the 2nd dose;

  13. Implementation of comprehensive health education actions that strengthen the immediate adoption of all the measures to contain transmission.

The implementation of these strategies to strengthen the ES of cases and contacts, systemically and universally, must be adapted to the reality of each community. It can only be conducted with adequate political, financial and technical/operational support. From a technical-scientific point of view, these measures have historically demonstrated efficacy, efficiency and effectiveness in epidemics and pandemics of communicable diseases, through different epidemiological studies conducted in different realities and contexts, made available here in the form of an articulated series of technical recommendations, aiming to contribute to mitigate the effects of the pandemic in this new phase.


  • *
    Presented to the Scientific Committee of the Northeast Consortium of Governors.
  • Financial support: none

Publication Dates

  • Publication in this collection
    15 Nov 2021
  • Date of issue


  • Received
    06 Aug 2021
  • Accepted
    06 Aug 2021
  • Preprint posted on
    17 Aug 2021
Associação Brasileira de Saúde Coletiva Av. Dr. Arnaldo, 715 - 2º andar - sl. 3 - Cerqueira César, 01246-904 São Paulo SP Brasil , Tel./FAX: +55 11 3085-5411 - São Paulo - SP - Brazil