City Of Manaus Research Articles

A TERCEIRIZAÇÃO NA CONSTRUÇÃO CIVIL

This article has the main purpose of discussing the importance of outsourcing in civil construction, whether or not it is viable for companies and for the worker. Initially, it will be discussed how outsourcing is defined, then different opinions on the subject will be presented, pointing out the advantages and disadvantages of this type of management, it will also be presented which services of a particular company in the construction industry in the city of Manaus were outsourced. The methodology of the present study was descriptive, carried out through research with bibliographic surveys in books, magazines, theses, articles, websites and through the visit made to the company mentioned above. After analyzing the data in this article, it is possible to state that despite the risks that companies face when outsourcing some services, it is considerable feasible, due to the reduction of costs and the good quality obtained by contracting outsourced companies, especially those that become specialists in certain services, however there are companies that offer their services, but that are not qualified and precarious working conditions for their employees, which must be observed by the contracting company so that it will not be penalized in the future.

Percepção dos alunos do ensino fundamental II de escolas públicas sobre o bem-estar de pets

The research aimed to evaluate the perception of elementary school II students about the well-being of pets in state public schools in the city of Manaus - AM. A questionnaire was applied to students in two state schools. A total of 223 students were approached, where 70.85% have pets in their home, being dogs, cats or even other species. Most of the interviewees acquired the animals as a gift or bought. They know that animals transmit diseases, but they do not take them to the veterinarian and do not vaccinate periodically. Therefore, the interviewees showed that they have basic information about the well-being of pets, but more work on handling domestic animals still needs to be done.

Percepção dos alunos do ensino fundamental II de escolas públicas sobre o bem-estar de pets

The research aimed to evaluate the perception of elementary school II students about the well-being of pets in state public schools in the city of Manaus - AM. A questionnaire was applied to students in two state schools. A total of 223 students were approached, where 70.85% have pets in their home, being dogs, cats or even other species. Most of the interviewees acquired the animals as a gift or bought. They know that animals transmit diseases, but they do not take them to the veterinarian and do not vaccinate periodically. Therefore, the interviewees showed that they have basic information about the well-being of pets, but more work on handling domestic animals still needs to be done.

The burnout syndrome in a woman lawyer in the city of Manaus

This article is part of a master’s thesis presented at the Universidad Europea del Atlántico that dealt with a field research that investigated: The burnout syndrome in a lawyer from the city of Manaus, and had as a problem: what are the effects of the burnout syndrome in women lawyer from the city of Manaus? Its general objective was to analyze the cases of syndrome of female lawyers in the city of Manaus, seeking to understand its effects on the daily life of the same. Five women were interviewed who had presented the problem in the last 2 years in the city of Manaus, State of Amazonas, Brazil. The results indicate that the therapeutic approach is multimodal and is based on recommendations for the psychosomatic management of functional somatic syndromes, complemented by interventions related to the work situation. It is concluded that Burnout among female lawyers has been little studied. The main burnout factors of the investigated workers are: professional factors and a high level of responsibility.

Multidrug-resistant Klebsiella pneumoniae: a retrospective study in Manaus, Brazil.

Klebsiella pneumoniae is an opportunistic pathogen that can cause several infections, mainly in hospitalised or immunocompromised individuals. The spread of K. pneumoniae emerging virulent and multidrug-resistant clones is a worldwide concern and its identification is crucial to control these strains especially in hospitals. This article reports data related to multi-resistant K. pneumoniae strains, isolated from inpatients in the city of Manaus, Brazil, harbouring virulence and antimicrobial-resistance genes, including high-risk international clones belonging to clonal group (CG) 258. Twenty-one strains isolated from different patients admitted to four hospitals in the city of Manaus, located in the state of Amazonas, Northern Brazil (Amazon Rainforest region) were evaluated. The majority of strains (61.9% n = 13) were classified as multidrug-resistant (MDR), and five strains (23.8%) as extensively drug-resistant (XDR). Several virulence and antimicrobial-resistance genes were found among the strains and eight strains (38.1%) presented the hyper-mucoviscous phenotype. MLST analysis demonstrated a great diversity of STs among the strains, totaling 12 different STs (ST11, ST23, ST198, ST277, ST307, ST340, ST378, ST462, ST502, ST3991, ST3993 and ST5209). Three of these (ST11, ST23 and ST340) belong to CG258.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00203-022-02813-0.

Dynamics of COVID-19 in Amazonia: A history of government denialism and the risk of a third wave

The city of Manaus (the capital of Brazil’s state of Amazonas) has become a key location for understanding the dynamics of the global pandemic of COVID-19. Different groups of scientists have foreseen different scenarios, such as the second wave or that Manaus could escape such a wave by having reached herd immunity. Here we test five hypotheses that explain the second wave of COVID-19 in Manaus: 1) The greater transmissibility of the Amazonian (gamma or P.1) variant is responsible for the second wave; 2) SARS-CoV-2 infection levels during the first wave were overestimated by those foreseeing herd immunity, and the population remained below this threshold when the second wave began at the beginning of December 2020; 3) Antibodies acquired from infection by one lineage do not confer immunity against other lineages; 4) Loss of immunity has generated a feedback phenomenon among infected people, which could generate future waves, and 5) A combination of the foregoing hypotheses. We also evaluated the possibility of a third wave in Manaus despite advances in vaccination, the new wave being due to the introduction of the delta variant in the region and the loss of immunity from natural contact with the virus. We developed a multi-strain SEIRS (Susceptible-Exposed-Infected-Removed-Susceptible) model and fed it with data for Manaus on mobility, COVID-19 hospitalizations, numbers of cases and deaths. Our model contemplated the current vaccination rates for all vaccines applied in Manaus and the individual protection rates already known for each vaccine. Our results indicate that the SARS-CoV-2 gamma (P.1) strain that originated in the Amazon region is not the cause of the second wave of COVID-19 in Manaus, but rather this strain originated during the second wave and became predominant in January 2021. Our multi-strain SEIRS model indicates that neither the doubled transmission rate of the gamma variant nor the loss of immunity alone is sufficient to explain the sudden rise of hospitalizations in late December 2020. Our results also indicate that the most plausible explanation for the current second wave is a SARS-CoV-2 infection level at around 50% of the population in early December 2020, together with loss of population immunity and early relaxation of restrictive measures. The most-plausible model indicates that contact with one strain does not provide protection against other strains and that the gamma variant has a transmissibility rate twice that of the original SARS-CoV-2 strain. Our model also shows that, despite the advance of vaccination, and even if future vaccination advances at a steady pace, the introduction of the delta variant or other new variants could cause a new wave of COVID-19.

Inequalities and the COVID-19 pandemic in Brazil: analyzing un-coordinated responses in social assistance and education

AbstractThis paper contributes to discussions about subnational responses to the coronavirus disease (COVID-19) pandemic in federal countries. In the scholarship on federalism and public policy, few studies seek to understand the factors that shape subnational differences in welfare levels. This article seeks to better understand this issue in Brazil by exploring how, in a context with little national-level coordination, subnational governments tackle the inequalities exacerbated by the COVID-19 pandemic. This study analyzes two social policy areas with distinct national-level coordination mechanisms and federal responsibilities: social assistance and education. Two multi-level cases are examined: the states of Amazonas and São Paulo and the cities of Manaus and São Paulo. This analysis relies on quantitative data, mainly social indicators, and qualitative data collected through documents and in-depth interviews. Social assistance and education policy actors in Amazonas and São Paulo faced at times significant obstacles adapting and/or creating policies to tackle inequalities, resulting in a fend-for-yourself federalism and fragmented subnational policies. Differences in subnational responses can be explained by distinct policy legacies and previous capacity, which were key in organizing a useful response to the pandemic. However, to fully explain subnational responses, the role of actors within institutional contexts must also be taken into account. In social assistance, shared responsibilities among different levels of government led to competition and credit claiming dynamics, reinforcing fragmented and uncoordinated responses. In education, decentralization and more stable funding allowed political leadership to activate and mobilize subnational capacities and other actors at the subnational level, producing more sustainable responses.

Reinfection by the SARS-CoV-2 Gamma variant in blood donors in Manaus, Brazil

BackgroundThe city of Manaus, north Brazil, was stricken by a second epidemic wave of SARS-CoV-2 despite high seroprevalence estimates, coinciding with the emergence of the Gamma (P.1) variant. Reinfections were postulated as a partial explanation for the second surge. However, accurate calculation of reinfection rates is difficult when stringent criteria as two time-separated RT-PCR tests and/or genome sequencing are required. To estimate the proportion of reinfections caused by Gamma during the second wave in Manaus and the protection conferred by previous infection, we identified anti-SARS-CoV-2 antibody boosting in repeat blood donors as a mean to infer reinfection.MethodsWe tested serial blood samples from unvaccinated repeat blood donors in Manaus for the presence of anti-SARS-CoV-2 IgG antibodies using two assays that display waning in early convalescence, enabling the detection of reinfection-induced boosting. Donors were required to have three or more donations, being at least one during each epidemic wave. We propose a strict serological definition of reinfection (reactivity boosting following waning like a V-shaped curve in both assays or three spaced boostings), probable (two separate boosting events) and possible (reinfection detected by only one assay) reinfections. The serial samples were used to divide donors into six groups defined based on the inferred sequence of infection and reinfection with non-Gamma and Gamma variants.ResultsFrom 3655 repeat blood donors, 238 met all inclusion criteria, and 223 had enough residual sample volume to perform both serological assays. We found 13.6% (95% CI 7.0–24.5%) of all presumed Gamma infections that were observed in 2021 were reinfections. If we also include cases of probable or possible reinfections, these percentages increase respectively to 22.7% (95% CI 14.3–34.2%) and 39.3% (95% CI 29.5–50.0%). Previous infection conferred a protection against reinfection of 85.3% (95% CI 71.3–92.7%), decreasing to respectively 72.5% (95% CI 54.7–83.6%) and 39.5% (95% CI 14.1–57.8%) if probable and possible reinfections are included.ConclusionsReinfection by Gamma is common and may play a significant role in epidemics where Gamma is prevalent, highlighting the continued threat variants of concern pose even to settings previously hit by substantial epidemics.

Cryptoccoccal meningitis in post-covid 19 patient in the city of manaus: Case report

Cryptococcosis is a cosmopolitan and opportunistic mycosis, caused mainly by the etiological agent Cryptococcus neoformans, through the inhalation of fungal structures, especially in bird feces. The aim of this study was to report a reported case of cryptococcal meningitis in an immunosuppressed patient due to previous COVID-19 infection in the city of Manaus-AM, as well as to implement health education actions to prevent cryptococcosis in the region of the disease. Information about the case was obtained through access to the database of the Information System for Notifiable Diseases (SINAN), made available by the Center for Control of Zoonoses Dr. Carlos Durand (CCZ), an agency belonging to the Municipal Health Department of Manaus (SEMSA). The case patient, male, presented symptoms such as headache, fever, vomiting, seizures, neck stiffness, petechiae and hemorrhagic suffusions, hearing loss and signs of Kernig and Brudzinski. In a zoosanitary visit to the site of the injury, the presence of pigeon excreta on the walls of the residence was found, and cleaning was carried out without the use of personal protective equipment (PPE’s). The contact with the residents evidenced the lack of information about the zoonosis addressed, including the risk of transmission of cryptococcosis by pigeons, facts that make necessary more sanitary actions on zoonoses among the population of Manaus.

Association of Functional Disability and Biopsychosocial Factors in Older Adults With Low Back Pain Who Live in the Amazonas State Brazil: A Cross-Sectional Study

ObjectiveThe purpose of this study was to identify social and clinical factors associated with levels of functional disability (FD) in older adults with low back pain (LBP) in the city of Manaus, Amazonas, Brazil. MethodsA cross-sectional study of 557 adults with LBP aged ≥60 years was completed. Sociodemographic and clinical features, pain intensity (Numeric Rating Scale), FD (Roland Morris Disability Questionnaire), physical activity (International Physical Activity Questionnaire-short version), body mass index, educational level, health perception, emotional level, and self-reported diseases were evaluated. Statistical analysis was used to verify the association between quantitative variables and a group; Student t test or Mann-Whitney test, and analysis of variance (normality assumption) or Kruskal-Wallis test (non-parametric), P value of less than .05. ResultsThere were 81.3% female participants, 54.9% self-reported their race and/or skin color as brown, and 37.8% were sedentary. Pain intensity scores were 6.26 ± 2.19 in female participants and 5.82 ± 1.84 in male participants. Mean FD scores were 11.68 ± 6.08 for female participants and 9.61 ± 5.76 for males participants, although 39.7% of the total group presented with severe disability (score ≥14) and FD was associated with female sex (P = .001), physical activity (P≤ 0.001), body mass index (P≤ .001), emotional level (P < .001), and health perception (P < .001). ConclusionIn this group of older adults with LBP, FD was associated with female sex, level of physical activity, body mass index, emotional level, and health perception. Many factors that were identified with FD are modifiable; therefore, interventions, such as nutrition education and re-conceptualization of self-emotional and health perception, may have potential to help in preventing and reducing FD.

Inter-Regional Dynamics of Markets and Criminal Governance in Fortaleza and Manaus in Comparative Perspective

This article discusses how the social roles played by factions constitute a new type of criminal governance that is enforced by armed groups and has led to organizational innovation in prisons in the Brazilian cities of Manaus and Fortaleza. Factions act efficiently to increase their membership and establish their legitimacy. Values and moral orientations, delegation of roles, expansion of access to firearms and financial resources, annexation of territories, expulsion of residents and resistance to police attacks are elements of the local governance of everyday life. We also describe the mechanisms of cooperation and conflict between state and criminal governance.

Fluoride Concentration in Public Water Supply in a City in the Amazon Region

Objective: To analyze the fluoride concentration in the public water supply in Manaus, Brazil. Material and Methods: Water samples were collected in 50 mL polyethylene bottles, identified, and labeled. The collection was performed from September 2016 to August 2018. For the selection of collection points, all neighborhoods of the city of Manaus, divided into four health districts (North, South, East, and West), were mapped. From each district, 30 samples were collected, totaling 120 monthly samples. Water samples were analyzed using an ion analyzer, ORION 720-A, and a specific electrode, ORION 96-09. The ion analyzer and electrode were calibrated in standard solutions. The levels were classified in intervals based on technical consensus to guide the health surveillance agencies. Results: Of the 2,874 water samples, 50.3% were within the recommended range, and 49.7% were inadequate, with 31.6% considered above the parameters and 18.1% below. Among the districts, the North had the highest percentages of unsatisfactory samples, resulting in limited action to prevent tooth decay. During the 24 months of analysis, there were large oscillations in the values in all four districts of Manaus. Conclusion: Results reinforce the importance of heterocontrol for the city to guarantee the effectiveness of this public health measure.

Evaluation of the economic viability of grid-connected photovoltaic systems in different Brazilian regions

This study aimed at the dimensioning and economic analysis of grid-connected photovoltaic systems in different cities in Brazil. As a criterion for the selection of the cities of interest, it was considered the capital with the highest number of residences in each of the five regions of the country, as well as the city where the authors are established, namely the cities of Salvador, Manaus, Goiânia, São Paulo, Curitiba, and Cascavel. Based on local characteristics and adopting an average monthly electricity consumption of 400 kWh, was developed the dimensioning of the photovoltaic systems, adopting the methodology presented by Pinho and Galdino (2014). Based on the components determined for the systems, budgets were made to enable their implementation. The investments to be made varied between US$ 4,682.97 and US$ 5,326.06. From these values, economic analyses were made using the discounted payback method. The projects presented different payback times, with the shortest payback time to the city of Manaus, with 9 years and the longest in the city of Curitiba, with 15 years. Therefore, it was confirmed the research hypothesis that the regional characteristics linked to the dimensioning of the photovoltaic systems directly affect the time of return on investment.

The influence of change on sense of coherence on dental services use among adolescents: a two-year prospective follow-up study

BackgroundTo investigate the influence of change on sense of coherence (SOC) on dental services use in adolescents over a two-year period.MethodsA prospective follow-up study was conducted involving 334 12-year-old adolescents from public schools in the city of Manaus, Amazonas, Brazil. The predictors of use of dental services in the last 12 months were selected according to the Andersen’s behavioural theoretical model. The predisposing factors included sex, self-reported skin colour and SOC. The enabling factors were dental insurance, monthly family income and parents/guardians schooling. Dental pain, perceived oral health status, dental caries and gingival status were used to assess need factors. Multivariable Poisson regression with robust variance was used to estimate incidence-rate ratios (IRR) and 95% confidence intervals between the independent variables and use of dental services.ResultsAdolescent’s SOC scores decreased significantly between baseline and one-year follow-up. SOC decline decreased the likelihood of using dental services in the last 12 months (IRR = 0.96 95%CI 0.92–0.99). Dental caries (IRR = 1.03 95%CI 1.01–1.04) and gingival bleeding (IRR = 1.01 95%CI 1.01–1.02) remained associated with use of dental services in the last 12 months. Adolescents with dental pain were more likely to have visited a dentist in the last year (IRR = 1.03, 95%CI 1.01–1.06).ConclusionSOC decrease over one-year period was a meaningful factor of dental services use among 12-year-old adolescents. Dental pain and clinical conditions were also relevant factors that can influence use of dental services in this group.

Impacts of the New NR-1 on the Reduction of Financial Costs of Micro Enterprises: A Study of Multiple Cases in the Sectors of Restaurant, Bakery and Textile Industry

The costs with the safety and health of employees are essential to guarantee the integrity of the workforce and maintain the productivity of the organization, nevertheless, the procedures and bureaucracy encountered by small entrepreneurs are a challenging factor for the class supporting a Management disproportionate risk for the size of the activities. That said, the NR-1 is a standard responsible for noting general actions which employers must comply with related to the Safety and Health of their employees in the most diverse work environments. In 2019, the Standard underwent changes through Ordinance No. 915 directly reflecting MEI’s, micro and small businesses covering matters such as PPRA and PCMSO. This article seeks, through a case study, to analyze the economic impact obtained by altering the NR-1 in three companies from different sectors located in the city of Manaus. Through analysis, it was possible to prove the economic effectiveness of the standard in the companies studied, providing speed and ease in the legal processes, in addition to facilitating the managerial routine.

Processes Standardization: A Case Study in the Form of Supply in a Company of the Two Wheels of Manaus

This article aims to study the application of standardization techniques in a two-wheel hub company in the city of Manaus, more specifically in the subassembly sector of the chassis, responsible for the preparation of parts to supply the assembly line. The methodologies used were the 5S methodology, which is proven very effective in identifying and eliminating waste and increasing efficiency; the standardization of intermediate stock, to improve the performance of the purchasing and business sectors, and finally, the PDCA cycle, to identify needs and find suitable, low-cost solutions. From the data collected, the problem was defined as the three worst parts, which are the mudguard, rear fork, and top cover, as it was found that they are recurrent in more than 50% of the models produced. These defects are due to the improper storage of the parts, which present scratches and beat marks. The need to establish an ideal condition of ideal storage was raised, and a manual was elaborated in which basic actions are listed to avoid small defects. After applying the mentioned tools and methodologies, the company managed to reduce the occurrence of small defects.

Risk Prediction of Delay in the Execution of Public Works Through Fuzzy Logic

In Manaus, delays in public constructions are not uncommon as their execution deadlines are often extrapolated, even though such deadlines are obtained through preliminary technical studies. The causes that give rise to such delays are varied ranging from the occurrence of rain to the addition of quantities of existing services or additions of new services. In this research, we sought to obtain a model, using fuzzy logic, to predict the risk of delay that some variables may cause in the period of execution of the work, allowing the public administration or the contracted company to adopt measures they consider essential to mitigate this delay. Initially, documentary and bibliographic research were carried out to identify the causes that most contribute to the occurrence of delays in the works. Once these causes were identified, the construction of the fuzzy inference system was started, with six of the most significant causes identified in the research being considered as linguistic variables, namely: the hiring factor, which corresponds to the quotient between the value of the proposal. of the company and the amount budgeted by the administration; the value of the work, which is the value of the contract for the work; the engineering execution drawing, which are the engineering drawings used in the works; the alteration of quantities, which are changes in the quantities of existing services or addition of new services; authorization from public agencies, which corresponds to the permission or support of any public agency or public company for the execution of the work; and the rain. For the simulation of the created fuzzy inference system, real data from four public works were entered, and the answers of this simulation were satisfactory because they are confirmed by the documentation of the respective works. It is concluded that the system proved to be useful, as it was possible to predict the risk of delay in the execution of public works in the city of Manaus, and it can be used by both the public administration and the contractor to mitigate the causes of delays in the execution of public works.

Structural analysis of SARS-Cov-2 nonstructural protein 1 polymorphisms found in the Brazilian Amazon.

The coronavirus disease COVID-19 has been the cause of millions of deaths worldwide. Among the SARS-CoV-2 proteins, the non-structural protein 1 (NSP1) has great importance during the virus infection process and is present in both alpha and beta-CoVs. Therefore, monitoring of NSP1 polymorphisms is crucial in order to understand their role during infection and virus-induced pathogenicity. Herein, we analyzed how mutations detected in the circulating SARS-CoV-2 in the population of the city of Manaus, Amazonas state, Brazil could modify the tertiary structure of the NSP1 protein. Three mutations were detected in the SARS-CoV-2 NSP1 gene: deletion of the amino acids KSF from positions 141 to 143 (delKSF), SARS-CoV-2, lineage B.1.195; and two substitutions, R29H and R43C, SARS-CoV-2 lineage B.1.1.28 and B.1.1.33, respectively. The delKSF was found in 47 samples, whereas R29H and R43C were found in two samples, one for each mutation. The NSP1 structures carrying the mutations R43C and R29H on the N-terminal portion (e.g. residues 10 to 127) showed minor backbone divergence compared to the Wuhan model. However, the NSP1 C-terminal region (residues 145 to 180) was severely affected in the delKSF and R29H mutants. The intermediate variable region (residues 144 to 148) leads to changes in the C-terminal region, particularly in the delKSF structure. New investigations must be carried out to analyze how these changes affect NSP1 activity during the infection. Our results reinforce the need for continuous genomic surveillance of SARS-CoV-2 to better understand virus evolution and assess the potential impact of the viral mutations on the approved vaccines and future therapies.

Intense SARS-CoV-2 transmission among affluent Manaus residents preceded the second wave of the epidemic in Brazil

Intense SARS-CoV-2 transmission among affluent Manaus residents preceded the second wave of the epidemic in Brazil

High anti-SARS-CoV-2 antibody seroconversion rates before the second wave in Manaus, Brazil, and the protective effect of social behaviour measures: results from the prospective DETECTCoV-19 cohort

SummaryBackgroundThe city of Manaus, Brazil, has seen two collapses of the health system due to the COVID-19 pandemic. We report anti-SARS-CoV-2 nucleocapsid IgG antibody seroconversion rates and associated risk factors in Manaus residents before the second wave of the epidemic in Brazil.MethodsA convenience sample of adult (aged ≥18 years) residents of Manaus was recruited through online and university website advertising into the DETECTCoV-19 study cohort. The current analysis of seroconversion included a subgroup of DETECTCoV-19 participants who had at least two serum sample collections separated by at least 4 weeks between Aug 19 and Oct 2, 2020 (visit 1), and Oct 19 and Nov 27, 2020 (visit 2). Those who reported (or had no data on) having a COVID-19 diagnosis before visit 1, and who were positive for anti-SARS-CoV-2 nucleocapsid IgG antibodies at visit 1 were excluded. Using an in-house ELISA, the reactivity index (RI; calculated as the optical density ratio of the sample to the negative control) for serum anti-SARS-CoV-2 nucleocapsid IgG antibodies was measured at both visits. We calculated the incidence of seroconversion (defined as RI values ≤1·5 at visit 1 and ≥1·5 at visit 2, and a ratio >2 between the visit 2 and visit 1 RI values) during the study period, as well as incidence rate ratios (IRRs) through cluster-corrected and adjusted Poisson regression models to analyse associations between seroconversion and variables related to sociodemographic characteristics, health access, comorbidities, COVID-19 exposure, protective behaviours, and symptoms.Findings2496 DETECTCoV-19 cohort participants returned for a follow-up visit between Oct 19 and Nov 27, 2020, of whom 204 reported having COVID-19 before the first visit and 24 had no data regarding previous disease status. 559 participants were seropositive for anti-SARS-CoV-2 nucleocapsid IgG antibodies at baseline. Of the remaining 1709 participants who were seronegative at baseline, 71 did not meet the criteria for seroconversion and were excluded from the analyses. Among the remaining 1638 participants who were seronegative at baseline, 214 showed seroconversion at visit 2. The seroconversion incidence was 13·06% (95% CI 11·52–14·79) overall and 6·78% (5·61–8·10) for symptomatic seroconversion, over a median follow-up period of 57 days (IQR 54–61). 48·1% of seroconversion events were estimated to be asymptomatic. The sample had higher proportions of affluent and higher-educated people than those reported for the Manaus city population. In the fully adjusted and corrected model, risk factors for seroconversion before visit 2 were having a COVID-19 case in the household (IRR 1·49 [95% CI 1·21–1·83]), not wearing a mask during contact with a person with COVID-19 (1·25 [1·09–1·45]), relaxation of physical distancing (1·31 [1·05–1·64]), and having flu-like symptoms (1·79 [1·23–2·59]) or a COVID-19 diagnosis (3·57 [2·27–5·63]) between the first and second visits, whereas working remotely was associated with lower incidence (0·74 [0·56–0·97]).InterpretationAn intense infection transmission period preceded the second wave of COVID-19 in Manaus. Several modifiable behaviours increased the risk of seroconversion, including non-compliance with non-pharmaceutical interventions measures such as not wearing a mask during contact, relaxation of protective measures, and non-remote working. Increased testing in high-transmission areas is needed to provide timely information about ongoing transmission and aid appropriate implementation of transmission mitigation measures.FundingMinistry of Education, Brazil; Fundação de Amparo à Pesquisa do Estado do Amazonas; Pan American Health Organization (PAHO)/WHO.